Otherware/Otherware_1_SB_Development.iso/mac/developm/scnote/fracapp.007/UFracApp.inc1.p

Text File | 1988-08-17 | 98KB | 2,151 lines

{------------------------------------------------------------------------------
#
#    Apple Macintosh Developer Technical Support
#
#    MacApp Color QuickDraw Fractal Sample Application
#
#    FracApp
#
#    UFracApp.inc1.p    -    Pascal Source
#
#    Copyright ⌐ 1988 Apple Computer, Inc.
#    All rights reserved.
#
#    Versions:    1.0                    8/88
#
#    Components:    MFracApp.p            August 1, 1988
#                UFracApp.p            August 1, 1988
#                UFracApp.inc1.p        August 1, 1988
#                FracApp.r            August 1, 1988
#                FracApp.make        August 1, 1988
#
#    This is a program to calculate the Mandelbrot set, allowing you to zoom in on areas
#    that are selected with the mouse.  There are some special color tricks played
#    in order to make the program more jazzy.  A special color table is used to give
#    smooth transitions from one color to the next.  Color table animation is also
#    supported, for the wowem effect of flowing Mandelbrot images.
#    The program is written in MacApp 1.1, which explains why it has a real user
#    interface.  Mandelbrot images take about 30 minutes to calculate.  It is
#    Juggler aware so you can put the program in the background where it will
#    continue to calculate, while you do something more important, like look at
#    the source code.  It also handles multiple documents, and reading/writing of
#    PICT files using the bottlenecks to minimize the memory hit.
#
#    This program is intended to be a real world example of handling color in a
#    nontrivial fashion.  As such it has some rather special color requirements,
#    and those don╒t match the current system architecture very well.  The program
#    is designed to be compatible with the future, it will not break in future
#    systems.  However, it does not use the Palette Manager, which means that
#    there will be situations where the colors will not look right in either FracApp
#    or another program running under MultiFinder.  The approach that FracApp
#    uses is thus not the preferred Apple approach and does NOT have the Apple
#    seal of approval from engineering.  The only way to get the stamp of approval
#    is to use the Palette Manager.  To do a program of this form, you cannot
#    use the Palette Manager without some extra hacks that are compatibility
#    risks in themselves.  So... use at your own risk.  If you are forced to revise your
#    program because you followed this as an example, you cannot gripe to Apple, since
#    it is not fully approved.  You just have to change your program, which I hope is no
#    big deal.  You can give this code to other people, as long as they recognize
#    that it is not fully approved too.
#
#    Unless you have very special color requirements, you should use the Palette
#    Manager.  It works for most things, and is much easier to use than the
#    approach taken here.  There are a few things it won╒t do of course, leading
#    to this code.  If you can do it, use the Palette Manager and save yourself
#    some grief.
#            Written in MacApp Object Pascal code.
#            Compatibility rating = 2.  (nothing will break, but it may not
#                always look correct.)
#
------------------------------------------------------------------------------}
{Copyright 1988 by Bob.  All rights reserved, since Bob has all rights.
    February 1, 1988.
    Written by Bo3b Johnson of Developer Technical Support. }

{ Version 1.0 }

{ The following is a list of features or bug fixes that could be added to the program:
  *** Check the segmentation.
  *** Bug with selection rectangle on edge of document, moving by 1 pixel.
  *** Make it run crashless using temp documents to store partial fractals.
  *** Updates could be cleaner so no partial fractals are displayed.
  *** Override window.updateevent so we can avoid the EraseRect on updates.
  *** Draw selection rect in offscreen, copy up to screen for flicker free selection.
  *** Crash on 3 monitor system during window drag.
  *** Could set the bytes directly in offscreen PixMap, skip using MoveTo:Line.
  *** Copy up from small picture up to big screen gets garbage, src rect too big?
  *** Allow a way to Zoom in using coordinates.
  *** Allow the user to set the colors used in display.
  *** Bigger penSize for fast, lo-res fractals.  Allow user to set size of pen.
  *** Add MacApp debugging stuff like Inspect and TList object checking.
  *** Some things for the reader to do to modify the program.
  }

{ Where does it fit:
    This is a series of sample programs for those doing development
    using Color QuickDraw.  Since the whole color problem depends
    upon the exact effect desired, there are a number of answers
    to how to use colors, from the simple to the radically complex.
    These programs try to cover the gamut, so you should use
    which ever seems appropriate.  In most cases, use the simplest
    one that will give the desired results.  The compatibility
    rating is from 0..9 where low is better.  The more known risks
    there are the higher the rating.


    The programs (in order of compatibility):

        SillyBalls:
            This is the simplest use of Color QuickDraw, and does
            not use the Palette Manager.  It draws randomly colored
            balls in a color window.  This is intended to give you
            the absolute minimum required to get color on the screen.
            Written in straight Pascal code.
            Compatibility rating = 0, no known risks.

        FracAppPalette:
            This is a version of FracApp that uses only the Palette
            Manager.  It does not support color table animation
            since that part of the Palette Manager is not sufficient.
            The program demonstrates a full color palette that is
            used to display the Mandelbrot set.  It uses an offscreen
            gDevice w/ Port to handle the data, using CopyBits to
            draw to the window.  The Palette is automatically
            associated with each window.  The PICT files are read
            and written using the bottlenecks, to save on memory
            useage.
            Written in MacApp Object Pascal code.
            Compatibility rating = 0, no known risks.

        TubeTest:
            This is a small demo program that demonstrates using the
            Palette Manager for color table animation.  It uses a
            color palette with animating entries, and draws using the
            Palette Manager.  There are two circles of animating colors
            which gives a flowing tube effect.  This is a valid case
            for using the animating colors aspect of the Palette Manager,
            since the image is being drawn directly.
            Written in straight Pascal code.
            Compatibility rating = 0, no known risks.

        FracApp:    (***)
            This is the ╘commercial quality╒ version of FracApp.  This
            version supports color table animation, using an offscreen
            gDevice w/ Port, and handles multiple documents.  The
            CopyBits updates to the screen are as fast as possible.  The
            program does not use the Palette Manager, except to
            provide for the system palette, or color modes with less than
            255 colors.  For color table animation using an offscreen
            gDevice w/ Port, it uses the Color Manager and handles the
            colors itself.  Strict compatibility was relaxed to allow for
            a higher performance program.  This is the most ╘real╒ of the
            sample programs.
            Written in MacApp Object Pascal code.
            Compatibility rating = 2.  (nothing will break, but it may not
                always look correct.)

        FracApp300:
            This doesn't support colors, but demonstrates how to create and
            use a 300 dpi bitmap w/ Port.  The bitmap is printed at full
            resolution on LaserWriters, and clipped on other printers (but
            they still print).  It demonstrates how to use a high resolution
            image as a PICT file, and how to print them out.
            Written in MacApp Object Pascal code.
            Compatibility rating = 1.  (The use of PrGeneral is slightly
                out of the ordinary, although supported.)
}

{ Reasons for this version of reality (the strategy):
    The main idea behind this program is to allow you to create and fool around
    with the Mandelbrot set, using this number cruncher wizzo computer we got
    here.  While we are making these documents, we also throw in a couple of
    special effects to make it more fun, like the special color mapping and the
    color table rotation.  This program is intended to be a real-life program,
    done as well as possible given current constraints.  The program is supposed
    to be something that somebody (who was silly perhaps) might try to sell.
    The idea is to pretend that we are developers as well, testing the development
    world as well as making a fun program.  Well, life╒s a bitch as a developer
    trying to write a program of this form.  No intentional shortcuts were taken
    in the program, but some things were left out due to time constraints.  Like
    all real programs, some people will like it and some people will hate it.  I
    hope you like it, but if you don╒t, send me some mail telling me why.

    The overall structure of the program is to have the MacApp Document object
    handle all the data.  This includes an offscreen gDevice and port that are
    the actual fractal data.  The View object uses the Document╒s data to draw
    into the window visible to the user.  The Document does all the work of
    calculating new fractals during Idle times.  It also handles saving the
    data to disk and reading it back.  The data files are PICT so as to be as
    compatible as we can.  The color table animation is handled by the Application
    object during its Idle processing.  The program handles zooming in to
    see closer views of the environment, using selection rectangles as you
    would expect.  This whole block of comments at the beginning are intended
    to describe some more macroscopic problems and structure.  In the code
    itself you will find the tactical comments dealing with how a specific
    operation is done.

    The fractal calculation is done by the CalcCity routine of the Document.  The
    Application object gets the DoIdle call, and he calls each document to
    have a pixel calculated in each document.  The calculation is done a pixel
    at a time so that it can be done in the background with no visible effect
    on the foreground app.  As each horizontal line of data is finished it is
    updated to the screen.  The algorithm is very simple.

    The color handling to be as nice as possible under MultiFinder is found in
    the AboutToLoseControl and RegainControl methods of the Application.  In
    addition, the color table animation is done by the RotateColors routine,
    called from the Application's DoIdle method after it gives some CPU time
    to each open document.  The handling of the gDevices on the system, essentially
    all the work the Palette Manager would have done for us can be found in
    the GarDevice methods.  Those handle changing the colors and color table
    animation.

    Allocating and using an offscreen gDevice and port are found in the Document
    object, as the BuildOffWorld method.  The port offscreen is used as a drawing
    environment once a pixel is calculated, as seen in DoIdle for the Document.


    You should use the Palette Manager if at all possible.  For other references
    see the other sample programs in this collection.
    This program does not fully use the
    Palette Manager.  I apologize.  The Palette Manager has two major
    flaws for a program of this form.  It does not provide a convenient way to
    remap the colors after the color table is scrambled so that updates to the
    screen can be as fast as possible; and it does not support a single animating
    palette used for multiple windows.  The first can be partially solved using the
    CopyBits to itself trick, but this is inconvenient while a fractal is being
    calculated.  The second can only be solved by incredible hacks, which
    would not be done in a commercial program.  The problem stems from having
    195 animating colors for each window, but I only wish to use 195 colors
    for the whole program, not each window.  In addition, this is 195 animating
    colors.  If they were standard colors, then the same entries in the table
    would be used for multiple windows. The answer to the problems
    was to use the Color Manager, and try to be as friendly as possible.  When
    the Palette Manager is fixed, the program can be revised to reflect these
    changes and live a much happier life.

    The Color Manager is used, primarily the SetEntries call in order to set
    the color enviroment the way we need it.  Color Search Procs are also
    used to map the fractals into devices that have fewer colors.  Using
    SetEntries can be a little rough since the Palette Manager is also using
    it to set the color environment and does not respect our use of the
    color table.  FracApp could be described as Palette Manager aware, but
    not friendly.  It uses the PM whenever it can, but for the fanciest effects
    it must bypass the PM.  Using the Palette Manager is far and away the
    most sensible thing to do, but we were stuck here with a low-performance
    program that would not be commercially viable.  If you don╒t need some
    of the high-end tricks played here, your life will be much easier if you
    use the Palette Manager instead.  In particular, FracApp knows and keeps
    track of all the Monitors connected to the machine, which is normally
    done by the Palette Manager.  If you can do it, save yourself some time
    and use the PM.

    This color changing will only be done if we have enough colors in the system
    to do the full blown fractal (ie. > kNumColors).  If not, we can╒t get a reasonable
    fractal anyway, so we will just do zebra fractals.  This way you can still
    use the program in lesser color modes, it just isn╒t as impressive.  This is far
    preferable to a ╘you must use 256 color mode╒ dialog.  Color table animation
    will only be enabled when running with enough colors.  If we have enough colors
    on a given monitor then we just set the ctSeeds to match to get a fast update.

    When we set up the offscreen gDevice, we set it up using a 3 bit iTable to save
    on memory that isn't used.  We don╒t use the iTable in the offscreen gDevice
    since it is never the destination of a CopyBits or color selection operation.
    There is thus no reason to waste memory on unused data.

    When a document is saved the color table from the offscreen gDevice is used.
    This is the clut resource that is used uniformly throughout the program.  If
    you hate my choice of colors, you can change the clut to something else and
    all should work the same (except old documents will map into something else).
    When the color animation is done, we don╒t rotate the offscreen guys, we just
    move a copy of the system color table around.

    There is a known bug with programs that animate the color table in the
    background.  This doesn╒t seem like a reasonable goal given the environment,
    but some programs wish to do this.  If they do, the color table will get
    munged up, giving you some wild effects.

    The Palette Manager is used to the extent that we have the System Palette
    (14 colors) attached to each window automatically.  If the window is on
    a monitor with not enough colors to do our thing, the Palette will be used
    instead, giving a fixed color environment so the fractals look the same
    each time they are displayed.  If we have enough colors on the device we
    walk all over the colors there, so the PM is not being used there.

    The Apple Menu was a special hack to make sure that it would draw in the
    right colors, and not be animated when we were doing the color table
    animation.  It is done by making sure that the system palette is always
    available, even when we hammer on the color table.  We hammer an
    extra 14 colors when we do it, and make sure the menubar is redrawn
    after we hammer.  To avoid having the Apple animate, we Reserve the
    entries we use.  When the menubar is drawn it will only match non-
    reserved entries.

    The program currently uses ScreenBits.Bounds as the determining size of the
    view and thus the fractal that is calculated.  This is OK, but a better approach
    would be to allow the user to specify the limits of the Fractal they want.  This
    involves adding another dialog and save defaults type of feature but is a better
    way to solve the problem since it is not obvious what the best size would be.
    ScreenBits.bounds is easy to use, but whenever there is no obvious best answer
    it is always better to let the user decide instead, that way they can╒t bitch.

    We have to be pretty rowdy about changing the color table.  In order to be sure that
    our colors are set up the right way, we need to check the depth and make sure
    the colors are right at each update event.  We may get an update during the program
    that comes from changing depth.  During any update, if we don╒t have enough
    colors to do the full fractal, we will use a color search proc to map the
    fractal into the color space available.  This will make zebra fractals, a
    reasonable compromise.

    Another goal of course was to get this thing done.  A goal that tends to slide
    away as more things are added to the program, so in true Macintosh style,
    the 1.0 version of the program is somewhat limited, and may not be fully
    debugged.  Some things specifically left out: printing the documents to
    a LaserWriter with grey scales instead, using temporary documents to
    make the program crashless (so you can start up where you left off, saving
    the computation it took to get there), an option to make the ╘pen╒ size bigger
    so you can do a low-res fractal to begin with.  These things are all admirable
    features to add, but you have to finish version 1.0 sometime, so this was it.
    These other things will be added if possible.

    Carefully watch the 881 flag with this MPW business.  There are a number of
    ridiculous problems associated with its use.  In particular the $LOAD files
    are dangerous to use with 881 and the combination of the two will often
    end up compiling successfully into a program that is garbage and will
    crash upon running it.  This, remind yourself, is a feature of the most
    powerful development system around.  In order to build currently, the main
    program MFracApp.p should be compiled with new $LOAD files and the 881
    flag turned off.  All of the MacApp sources should be compiled with a new
    $LOAD file and 881 turned off.  The last step should be to compile the UFracApp.p
    with the 881 flag turned on, and with new $LOAD files as well.  Beware or
    be prepared to spend a lot of time on something silly.  To solve this
    problem the Make file used with FracApp has a specific compile rule for
    the UFracApp file.  UFracApp also uses its own $LOAD file, that is different
    from the MacApp and MFracApp ones.  The 881 flag is not specifically
    required, but it makes code that uses the 881 directly instead of going
    through SANE for a speed up of about 10 times.  Since we are speed freaks
    here as well, the 881 option had to be used.  Given the problems, I would
    probably skip the 881 option and do the time critical pieces in assembler.

    If you want to know how long a fractal took to calculate there is a time
    stamp saved in the file header.  It is no longer drawn in the window since
    it is not accurate when the program has run in the background or if there
    are multiple documents open.  This could be added again if desired.
    This will be made more accurate in the future, probably
    using a calculation that gives us a once through the loop calculation
    in units of TimeDBRA, so we can be more machine independent.

    Notably I am aware of the fact that this program does not really calculate
    Fractals.  Actually it calculates and displays the Mandelbrot set which is
    not self-similar so it cannot really be called a fractal.  It is distressing to
    add to the confusion as to what fractals are, but it is too late.  For more
    information on Fractals and the Mandelbrot set (no umlaut on the o), you
    could see Mandelbrot╒s book ╘The Fractal Geometry of Nature╒, but it is
    pretty mathematical and not all that helpful.  A better source is the
    Peitgen-Richter book ╘The Beauty of Fractals╒, which has a do it yourself
    section in the back.

    The program is structured primarily around the document.  The document is
    the object to create and maintain the offscreen gDevice & port.  The document
    converts the offscreen data into a PICT file when saved or restored.  The
    document also does the calculation of the fractal, keeping the offscreen data
    up to data as it goes along.  The view only handles taking the document data
    and displaying it.

    For the zoom operation, there was no really great way to handle the new
    document case based on another document.  This is a little strange to be
    doing, and the structure of MacApp was such that we couldn╒t get to the
    data desired at the right time.  The logical place to put it in at
    DoMakeDocument was too early to have the gDevice allocated and ready
    to start more stuff.  The problem was resolved by using global variables
    to transmit the information to the other piece of the program that
    might need it.  Essentially DoInitialState decides if this is a brand new
    base level document or a zoom in based on the state of the global variables.

    When we feel obligated to go whap on a monitor and change the color table,
    we use a special TList built during the IFracApplication.  The TGarList is
    a list of display devices in the system.  Whenever we need to do something
    to a display device we do an Each operation and do it to each device in the
    system.  This simplifies the handling of multiple monitors dramatically.
    Thank you MacApp, this is cool.  The GarDevices have a number of methods
    that handle the special things we do to the gDevices in the system.  When
    the Palette Manager is more robust, this GarDevice object can probably
    be removed, since virtually all of the work done by the GarDevice are things
    that the Palette Manager will handle for us.

    The MacApp memory management approach is used as well.  The big pieces
    used by the Documents come out of permanent memory, helping to avoid
    a crash from no memory.  When we allocate something that will be thrown
    away immediately, like a spare color table or something, it of course
    comes out of normal memory.  We did not do a full blown memory analysis
    of the program since it is such a memory hog anyway.  The mem! resource
    is set up in a form that is roughly close (a bit high) without trying to be
    extra accurate.  When a document takes 400K of RAM to open it hardly
    seems relevant to make sure the mem! is accurate to 2K.  Because of this
    somewhat cavalier approach you may not be able to open a document in
    a few cases where you really should be able to.  The mem! in use of 40K
    is close with a +2K/-10K error on how big it should really be.

    The QuickDraw BottleNecks are used to both read and write the actual
    fractal data from/to the disk.  This is done since the data in the document
    may be very large (100K) and if we just spool the data from the file
    we don't actually have to use that extra hunk of memory.  We have to read
    the data anyway, so we go ahead and just read it in as we play it back.
    As it is played back it goes into the offscreen gDevice's pixMap, so we
    have the data to display.  No memory hit for the document is a big win.
    When writing the data, the same thing is true so we don't have to have
    a huge handle to hold the picture data itself.  We also avoid the problem
    of not having enough memory to create the picture in the first place,
    making a document unsaveable.  That is particualarly annoying, and
    is easy to avoid using the spooling approach.

    While in the foreground we set the color table to be our special set of
    colors, making the display as good as we can get it for us.  This has the
    side effect of making programs in the background change.  When we are
    in the background we make no claims on the color table.  We don╒t bother
    to Protect entries, but we Reserve the entries so that Color2Index
    will find colors other than the animating ones we are using.  This is
    specifically to make the Apple Menu look correct, but will also help
    the programs in the background to avoid having them animate when
    we are in the front.  When they are redrawn, they will use the non-
    animating entries out of the color table.  Again, in the background
    we make no claims, so any color in the table is available for use.

    With thanks to Skippy Blair for the discussions of color QuickDraw and the
    Palette Manager.  Thanks to Darin Adler for further discussion of the Palette
    Manager and for good suggestions on making it more MacApp friendly.
    Thanks too to Dave McGary for the discussion on color mapping in other than 256
    color mode, and for coming up with the solution to use a MOD or DIV to wrap
    the excess colors around, making it come out in the stripes when not enough
    colors are available.
    }


    { Global variables.  }
VAR
    gRotateOn:            BOOLEAN;                { whether we are color animating or not. }
    gStaggerCount:     INTEGER;                { for staggering windows. }
    gGarList:                TList;                    { List of gDevices in system. }
    gBackGround:        Boolean;                { flag if we are in background or not. }
    gOurColors:            CTabHandle;            { color table we use as a source for documents. }
    gRealMin,
    gRealMax,
    gImagMin,
    gImagMax:            Extended;                { used for zooming in operation. }

        { The next globals are used for the QuickDraw bottlenecks when reading or
            writing a picture to disk.  These are needed, since the bottlenecks cannot
            be owned procedures. }
    gPictSize:            LongInt;                { number of bytes used for saving a PICT. }
    gPictError:            OSErr;                    { do some error handling in bottleneck. }
    gPictRefNum:        Integer;                { Need the refnum of the open file too. }
    gPictHandle:            PicHandle;            { for reading/writing a picture. }


{ Set some compiler options that we desire for the main body of code only.  You
    might wish to leave on the range checking, but I was not satisfied with having
    to push and pop in the code, and was not pleased with the slowdown in performance.
    These can be dangerous to turn off, especially the $H.  For those who use MPW
    more than I, you probably want to make these settable from the command line,
    or use the MacApp debug or no-debug compile time variables.  }
{$PUSH}        { Save the compiler state before we change it. }
{$D+}            { Debugging labels on for the code here. }
{$R-}            { No range checking to make things faster. }
{$OV-}            { No overflow checking either. }
{$H-}            { No handle checking to avoid compiler complaints on WITHs.  Be careful. }
{$N+}

{-------------------------------  Application  -------------------------------}

PROCEDURE TFracAppApplication.IFracAppApplication(itsMainFileType: OSType);

VAR        I:                        Integer;
            nextDevice:        GDHandle;
            nextGar:            TGarDevice;

BEGIN
    gStaggerCount := 0;
    IApplication(itsMainFileType);
    fIdlePriority := 1;                        { say we need Idle time calls to TApp.DoIdle }
    gRotateOn := FALSE;                    { no color rotation as we start. }
    gBackGround := FALSE;                { not in background to start. }
    gRealMin := 0;                            { must be set to empty to start with. }
    gRealMax := 0;                            { so we do normal document open. }

        { Now allocate a color table that we will use whenever we create a new document
            or need to compare colors.  This is so we have the same color table for each
            document, as well having the ctSeed the same for them all. }
    gOurColors := GetCTable(kClut);                    { install our new desired one from clut }
    FailNil (gOurColors);

        { In order to handle the multiple gDevices that abound in Mac II, we need to make
            a TList of the gDevices so we can more easily keep track of them.  The TGarDevice
            objects will be used to keep track of the devices, one object for each gDevice.
            We need to set up this TList here though.  The GarDevice list won't change while
            the program is running.  We only add devices that are screen devices, to avoid
            any spurious devices that we don't care about.  When initialized each GarDevice
            will set up the color environment as best it can. }
    gGarList:= NewList;

    nextDevice := GetDeviceList;                        { First gDevice in system. }
    While  nextDevice <> NIL  DO BEGIN
        IF TestDeviceAttribute(nextDevice, screenDevice)  AND
                TestDeviceAttribute(nextDevice, screenActive)  THEN BEGIN
            New (nextGar);                                        { Make a new object for this device. }
            FailNil (nextGar);                                    { If not possible, we are toast. }
            nextGar.IGarDevice (nextDevice);            { Init the GarDevice object. }
        END;                                                            { Add a legitimate screen Device. }
        nextDevice := GetNextDevice(nextDevice); { move to next gDevice in chain. }
    END;    { While }
END;        { TFracAppApplication.IFracAppApplication }


    { OK, this is where a new document gets created.  This does the init for the
        document object itself.  After it is done, the view and window can
        be created, relying upon the data in the document. }
FUNCTION  TFracAppApplication.DoMakeDocument(itsCmdNumber: CmdNumber):
        TDocument; OVERRIDE;

VAR        aFracAppDocument:    TFracAppDocument;

BEGIN
    { Allocate and initialize the document}
    New(aFracAppDocument);
    FailNil(aFracAppDocument);

    { Now initialize the document fields, and set up the global state of the fractal
        to a default set of the starting fractal. }
    aFracAppDocument.IFracAppDocument;

    { We successfully created a document so we can return the document object for
        use by the application. }
    DoMakeDocument := aFracAppDocument;

END;    { TFracAppApplication.DoMakeDocument }


    { Performs Idle time processing for the application.  This will do the
        fractal calculation during the idle times.  It will allow each open
        document a chance to calculate.  The CalcCity is a method owned by
        each document that will get a call from the ForAllDocumentsDo.
        The documents don't use the DoIdle routine since we want each
        open document to get time, not just the one in the target chain. }
PROCEDURE  TFracAppApplication.DoIdle (phase: IdlePhase); OVERRIDE;

        { Give each document some CPU time. }
    PROCEDURE DoFractalCalc(aDocument: TFracAppDocument);

    BEGIN
        aDocument.CalcCity;                        { give the document its time to calc. }
    END;

        { Give each GarDevice the message to rotate colors. }
    PROCEDURE DoRotateColors(curGar: TGarDevice);

    BEGIN
        curGar.RotateColors;                        { tell the device to rotate colors if possible. }
    END;

BEGIN
    IF phase = IdleContinue  THEN  BEGIN

            { Send the message to each open document to calculate the next pixel. }
        ForAllDocumentsDo (DoFractalCalc);

            { Now we have calculated the next pixel in each document.  If the Rotate Colors menu
                option has been checked we want to rotate the color table using our routine.  We
                need to rotate all color tables in devices we can see, so we'll use the GarList to
                do them all. }
        IF  (gRotateOn) AND (gFrontWindow <> NIL)  AND (NOT gBackGround)  THEN
                gGarList.Each (DoRotateColors);
    END;
END;        { TFracAppApplication.DoIdle }


    { Set up the menus choices in Fractal Menu.  Set the Rotate Colors choice to
        be enabled if we have a device with enough colors, and set the check mark
        on if it has been chosen.  We will go through the chain of devices to see if
        any are capable of rotation, and if so will enable the menu.  If we have a
        saved color table for any device, that device can do rotation. }
PROCEDURE TFracAppApplication.DoSetupMenus;  OVERRIDE;

VAR        rotateFlag:    Boolean;


    PROCEDURE  CheckRotate (curGar: TGarDevice);

    BEGIN
        IF curGar.fColorTable <> NIL  THEN rotateFlag := TRUE;
    END;

BEGIN
    INHERITED DoSetupMenus;                                    { Do mainline stuff first. }

    rotateFlag := FALSE;                                                { Assume we can't do it. }
    gGarList.Each (CheckRotate);                                { Change flag if needed. }

    EnableCheck (kRotateColors, rotateFlag, gRotateOn);    { enabled, and checked or not. }
END;        { TFracAppApplication.DoSetupMenus }


    { Handle the menu choice out of the Fractal Menu for Rotate Colors.  This will either
        set or unset the check mark, thus enabling or disabling the color rotation
        performed in the Idle loop. }
FUNCTION TFracAppApplication.DoMenuCommand(
                            aCmdNumber: CmdNumber): TCommand;  OVERRIDE;

BEGIN
    DoMenuCommand := gNoChanges;            { assume no command object returned. }

    CASE  aCmdNumber  OF
        kRotateColors:
            { Chose the rotate colors menu option.  We want to set the check mark, or unset it
                if already there, and reflect the menu state in our document variable which is
                used to rotate the color list at Idle time. }
            BEGIN
                gRotateOn := NOT  gRotateOn;            { invert the state of menu option. }
            END;        { kRotateColors }

        OTHERWISE
            DoMenuCommand := INHERITED  DoMenuCommand (aCmdNumber);    { next guy in chain. }
    END;        { CASE aCmdNumber }
END;        { TFracAppApplication.DoMenuCommand }


    { When we are switched in we need to reset the color table to our color table. }
PROCEDURE TFracAppApplication.RegainControl(checkClipboard: BOOLEAN); OVERRIDE;

    PROCEDURE  SendPound (curGar: TGarDevice);

    BEGIN
        curGar.PoundColors;
    END;


BEGIN
    gBackGround := FALSE;                        { no longer in background. }

        { Change the color table on each gDevice in the system that has enough colors to
            support our fancy colors.  If any device has enough colors we will enable the
            rotation flag. }
    gGarList.Each (SendPound);

        { Call the inherited routine to do the normal regain control operations as well. }
    INHERITED    RegainControl (checkClipboard);
END;    { TFracAppApplication.RegainControl }


    { When we are switched out we need to restore the color table to be polite.  When
        the program is closed this routine is called as well, so we don't need to override
        the Close method in order to fix the color table on Quit. }
PROCEDURE TFracAppApplication.AboutToLoseControl(convertClipboard: BOOLEAN);
        OVERRIDE;

    PROCEDURE  SendUnPound (curGar: TGarDevice);

    BEGIN
        curGar.UnPoundColors;
    END;


BEGIN
    gBackGround := TRUE;                            { are going into background. }

        { Fix up every gDevice that needs it. }
    gGarList.Each (SendUnPound);

        { Call the inherited routine to do the normal work for losing control. }
    INHERITED    AboutToLoseControl (convertClipboard);
END;    { TFracAppApplication.AboutToLoseControl }



{-------------------------------  Document  -------------------------------}

    { An auxiliary method to set up the step constants for the fractal calculation.
        It is external since we need to set up the constants when we create a new
        fractal as a zoom in.   Sets up the width/height of fractal, the delta in each
        axis as a real number, and ensures that the starting min/max values for
        the figure are set to supply a 1:1 aspect ratio.  The step constants are
        zeroed to start the fractal anew.  Allocates no memory. }
PROCEDURE  TFracAppDocument.SetUpConstants;

BEGIN
    WITH fFracHeader  DO  BEGIN
        { Set up the iterations by calculating up the step constants, and the
            edges of the view area in pixels. }

        plotWidth := (calcRect.Right - calcRect.Left);
        plotHeight := (calcRect.Bottom - calcRect.Top);
        deltaP := (realMax-realMin)/(plotWidth-1);
        deltaQ := (imagMax-imagMin)/(plotHeight-1);

        { Force aspect ratio 1:1, making delta smallest of two.  This effectively grows
            one side or the other out, like rMax/iMax becoming bigger number. }
        IF deltaP > deltaQ  THEN  BEGIN
            deltaQ := deltaP;
            imagMax := deltaQ * (plotHeight-1) + imagMin;     { new maximum for q }
        END   { grow the q side }
        ELSE  BEGIN
            deltaP := deltaQ;
            realMax := deltaP * (plotWidth-1) + realMin;         { new maximum for p }
        END;  { grow the p side }

        { Now start the counters at zero, as the edge of the area to calc. }
        curCol := 0;  curRow := 0;

        { And the elapsed time is zero of course, since we are just starting. }
        elapsedTime := 0;
    END;        { WITH fractalDocument }
END;        { SetUpConstants }


    { Utility method to build the offscreen gDevice and offscreen Port that is used for
        the document data.  This happy fellow will allocate huge old hunks of Ram for
        the document and set up the initial state of the gDevice with the right color
        table and so on.  This is done as a utility routine since we don't know in advance
        how big the gDevice will be, and we want to make it as big as it was when the
        document was saved, reading it from the header.  If we are making a new
        document, the DoInitialState will call with the screen rectangle. }

PROCEDURE  TFracAppDocument.BuildOffWorld (sizeOfDoc: Rect);

VAR        oldPerm:             Boolean;
            dummy:                Boolean;
            docW, docH:        LongInt;
            fi:                     FailInfo;
            currDevice:        GDHandle;
            currPort:            GrafPtr;
            Erry:                    OSErr;

        { This is the error handler for when we get errors while making a new document,
            typically like running out of memory.  Since the Free method for the document
            will get called we don't have to chuck the things that normally get killed.
            Just set allocation back to normal (for the error message itself), the drawing
            environment back to normal and return.  }
    PROCEDURE DeathBuildOff (error: OSErr; message: LONGINT);

    BEGIN
        oldPerm := PermAllocation (oldPerm);    { Set memory back to previous. }

        SetGDevice (currDevice);                        { Set device back to main, just in case. }
        SetPort (currPort);
    END;

BEGIN
    currDevice := GetGDevice;                        { save current for error handling. }
    GetPort(currPort);

    { The memory used creating the view must be out of permanent memory, it is too
        big.  Any failure to get it from permanent memory will invoke the error handler. }
    oldPerm := PermAllocation (TRUE);

    CatchFailures(fi, DeathBuildOff);                { any failures, must be cleaned up. }

    { Let's set up the size of the rectangle we are using for the document. }
    docW := sizeOfDoc.right - sizeOfDoc.left;
    docH := sizeOfDoc.bottom - sizeOfDoc.top;


    { Now try to set up the offscreen bitMap (color).  If we fail we have to split,
        and we might since we may not have 300K or more (basically a full screen
        worth, which is unlikely to be less than 300K) for the pixMap.  Each document
        on screen will have a full pixMap for it.  Allocate a full screen size buffer in
        8 bit depth.  Also make it into a color port so we can draw into it normally and
        use it as a source for CopyBits.  Requires 8 bits deep for the number of colors,
        and sets up a buffer with that in mind, that is full docRect size with
        one byte per pixel as 8 bit mode.  This is width x height.  8 bits/byte. }
    fBigBuff := NewPtr (docW * docH);
    FailMemError;                                                { couldn't get it we die. }


    { OK, now we get wacko.  We need to create our own gDevice, since we want to have
        an offscreen device.  This needs to be done so that we have full control over the
        color table used, in order to save full 8 bit documents, even if we aren't in 8 bit
        mode when we save.  So...  We will start by creating a NewGDevice, that will
        allocate a temporary ITable, and PixMap with partial colorTable;  change the
        fields of the device's pixMap to our bitMap, with right size, depth, and rowbytes;
        init the fields of that device, including changing the color table to our color
        table created from our clut;  set that gDevice as the current one; then do the
        OpenCPort which will use the current gDevice to make its PixMap and color table;
        When we go to draw or save the data in the offscreen buffer,
        we need to set the current device so we use our color table, making all the
        colors come out right.  }

    { Now we need to do the piece to make an offscreen gDevice that is not connected
        to the screen.  Allocate a new one, with stub pixMap. }
    fDrawingDevice := NewGDevice (0, -1);            { -1 means unphysical device.  }
    FailNIL (fDrawingDevice);                                { If we failed, error out. }

    { Now init all the fields we can in the gDevice Record, since it comes uninitialized. }
    HLock ( Handle(fDrawingDevice) );
    WITH  fDrawingDevice^^  DO  BEGIN
        gdId := 0;                                                        { no ID for search & complement procs }
        gdType := clutType;                                        { color table type fer sure. }

        { Get the color table for the offscreen gDevice.  This is a copy of the global
            color table we created early on. }
        DisposCTable (gdPMap^^.pmTable);                { kill the stub that is there. }
        gdPMap^^.pmTable := gOurColors;                    { make a copy of our global color table. }
        Erry := HandToHand (Handle(gdPMap^^.pmTable)); { and stick it into this gDevice too. }
        FailOSErr (Erry);                                            { if not possible, blow out. }

        { build a new iTable for this device, based on the new color table.  3 bit res to
            save on memory since we don't need the iTable for our stuff.  If we fail here,
            we have some dumb error code like -151.  This is translated via the ╘errs╒
            resource into the ╘there is not enough memory╒ message instead. }
        MakeITable (gdPMap^^.pmTable, gdITable, 3);
        FailOSErr (QDError);                                        { no memory, we can leave here. }

        gdResPref := 3;                                                { preferred resolution in table. }
        gdSearchProc := NIL;                                        { no search proc. }
        gdCompProc := NIL;                                        { no complement proc. }
        { Set the gdFlags to be: color, ramInit, noDriver, screenActive }
        gdFlags := 2**0 + 2**10 + 2**14 + 2**15;    { set each bit we need. }

        { Now set up the fields in the offscreen PixMap correctly. }
        gdPMap^^.baseAddr := fBigBuff;                        { The base address is our buffer. }
        gdPMap^^.bounds := sizeOfDoc;                        { bounding rectangle to our device. }
        { one byte per pixel horizontally is rowBytes.  + $8000 to make it color port. }
        gdPMap^^.rowBytes := docW + $8000;
        gdPMap^^.pixelSize := 8;
        gdPMap^^.cmpCount := 1;
        gdPMap^^.cmpSize := 8;

        gdRect := sizeOfDoc;                                        { the bounding rectangle for gDevice, too. }
    END;        { With fDrawingDevice }

        { Now unlock the gDevice handle since it is in the System Heap.  The system
            can use it unlocked as well as locked so we try to help avoid fragmentation. }
    HUnLock ( Handle(fDrawingDevice) );

    { Yow, that was rough.  Now we have a fully initialized gDevice offscreen with its
        own colortable.  All color mapping should be done using that color table, and the
        drawing we do to it should make the saved pictures save that color table too.
        Set to our new device so we OpenCPort with all new parameters. }
    SetGDevice (fDrawingDevice);

    { After all of that, we have a gDevice which is complete.  It has the color table we want
        associated with it, from the clut, it has the right portBits.baseAddr and the right
        size.  It is complete, except that we can't draw into it using normal calls.  We thus
        need to make a port that we can use.  We have set the gDevice to be the one we just
        created, and when we OpenCPort we will get a copy of the fields we just set up in
        our new gDevice.  The port is simply an interface into our gDevice for drawing.
        Allocate a port record on the heap as a pointer.  We get the Port record out of
        permanent memory, but the actual opening of the port must use all the memory
        available to avoid blowing up (system error).  QuickDraw is very unfriendly.
        After it lives, we need to be sure we still have memory reserve, and if not, we
        exit, killing this document. }
    fDrawingPort := CGrafPtr( NewPtr (SizeOf (CGrafPort)) );    { address of C Port record. }
    FailNil (fDrawingPort);                                    { didn╒t get it, means we die. }

    { Now the world is created, put memory allocation back to temporary, so that the
        QD pieces can come out of temp memory as well.  No more permanent blocks are
        allocated by us, except for the port, which cannot fail or we die.  }
    dummy := PermAllocation (FALSE);

    OpenCPort (fDrawingPort);                                { make a new port offscreen. }
    FailNoReserve;                                                    { Make reserve, die if we can╒t }

        { QuickDraw is most obnoxious about making a port that is bigger than the screen,
            so we need to modify the visRgn to make it as big as our full page document.  It is
            OK to change this ports visRgn since we own it offscreen.  This is in case we
            are opening a document made on a different computer with a bigger screen. }
    RectRgn(fDrawingPort^.visRgn, sizeOfDoc);

        { Go whap on the other pieces of the port record to set it up to be offscreen. }
    fDrawingPort^.portRect := sizeOfDoc;

    { OK, we have a nice new color port that is offscreen.  It has a fancy color table that
        came from the clut that will be used for the owning window.  It is 8 bits deep,
        has 256 colors in its color table and has a rect the size passed in.  It has no
        pieces that are related to the main gDevice, so we shouldn't alter that by drawing
        in this port.  }

        { Clear the error handler chain, we don't make any more dangerous requests. }
    Success (fi);

        { Set the memory allocation to what we started with. }
    oldPerm := PermAllocation (oldPerm);

        { Now we have the offscreen PixMap, we need to initialize it to white. }
    SetPort (GrafPtr(fDrawingPort));
    EraseRect (sizeOfDoc);                { clear the bits. }

        { We are done drawing and stuff for now, so set the gDevice back to where it was. }
    SetGDevice (currDevice);
    SetPort (currPort);
END;    { BuildOffWorld }


    { Init for the FracAppDocument itself.  This sets up the Document object. }
PROCEDURE      TFracAppDocument.IFracAppDocument;

VAR        dummyTime:        LongInt;        { for picky compiler }

BEGIN
    { Set up failure mechanism in case IDocument fails}
    IDocument(kFileType, kSignature, kUsesDataFork,
            NOT kUsesRsrcFork, NOT kDataOpen, NOT kRsrcOpen);

    { Set the time in our starting time variable in case we are still calculating.
        Temp var is to make the picky compiler not get worried about the var
        parameter.  This routine can't move memory anyway, but it won't allow
        this use. }
    GetDateTime (dummyTime);
    fStartTime := dummyTime;

    fBigBuff := NIL;
    fDrawingPort := NIL;                                    { set up in case we fail in here. }
    fDrawingDevice := NIL;
END;    { TFracAppDocument.IFracAppDocument }


    { Does the work for a New operation, where we start with a new fractal
        that doesn't have any stored data.  This is to set up the view with no
        data and set up the fractal coordinates to the default.  It will use the size
        of the  main screen to make a new document, and create the offscreen
        world to match.  If the global variable of gRealMin and gRealMax are both
        nonzero, then we want to use the global state being passed us by the
        New Fractal handler.  This is for the zoom in. }
PROCEDURE TFracAppDocument.DoInitialState;  OVERRIDE;

BEGIN
    WITH  fFracHeader  DO BEGIN
        { Start by filling in the fields that never change. }
        fType := kSignature;            { creator of these documents. }
        hdrId := INTEGER ('FA');        { ID of the file, different from other PICT files. }
        version := 1;                        { version 1 files. 0 was old MandibleJug docs. }

        done := FALSE;                    { not done, starting brand new document. }

        { We start from scratch.  This is the standard set of coordinates to start
            the default Mandelbrot set.
            Set up the coordinates to do, saving state in header vars. }
        realMin := -2.5;  realMax := 1.5;
        imagMin := -1.5;  imagMax := 1.5;

            { If we are supposed to do a zoom in, use those numbers instead. }
        IF (gRealMin <> 0) AND (gRealMax <> 0)  THEN BEGIN
            realMin := gRealMin;        realMax := gRealMax;
            imagMin := gImagMin;    imagMax := gImagMax;
        END;

        { Set the fractal rectangle to be the full screen size. }
        calcRect := ScreenBits.bounds;

    END;        { With FracHeader }

        { Clear the state of the globals so any new documents will not be zoom in types. }
    gRealMin := 0;        gRealMax := 0;

        { Build the initial state of the document offscreen gDevice & port }
    BuildOffWorld (fFracHeader.calcRect);

        { Set up the rest of the constants that are used in the fractal, including
            the deltas in each axis and the step constants for stepping through
            each point in the fractal plane. }
    SetUpConstants;
END;        { TFracAppDocument.DoInitialState }


PROCEDURE TFracAppDocument.DoMakeViews(forPrinting: BOOLEAN); OVERRIDE;

VAR        aFracAppView:    TFracAppView;

BEGIN
    { Create a new view (failing if we can't), get a rectangle with
        the appropriate extent, and initialize the view. }
    New(aFracAppView);
    FailNil(aFracAppView);

    { Initialize the view for use as a drawing environment. }
    aFracAppView.IFracAppView (SELF, fFracHeader.calcRect);

    {save a reference to the view in a TFracAppDocument field, for use
        by DoMakeWindows}
    fFracAppView := aFracAppView;
END;    { TFracAppDocument.DoMakeViews }


PROCEDURE TFracAppDocument.DoMakeWindows; OVERRIDE;

VAR        aWindow:    TWindow;

BEGIN
    { Gets window definition from resource file; the window is to have both horizontal
        and vertical scrollbars, and is to have my 'fFracAppView' installed in it;
        NewSimpleWindow will exit via the failure mechanism if allocation fails.
        There is a palette associated with this window by Resource Id, so it will
        automatically get used when the window is created. }
    aWindow := NewSimpleWindow(kFracAppWindowID, NOT kDialogWindow,
                    kWantHScrollBar, kWantVScrollBar, fFracAppView);

    SimpleStagger(aWindow, kStaggerAmount, kStaggerAmount, gStaggerCount);
END;    { TFracAppDocument.DoMakeWindows }


    { This routine will size the current image as it goes to the disk.  It won't actually
        save any data or anything, but will merely watch the bytes go by keeping track
        of how many go by.  The size is used by DoNeedDiskSpace. }
PROCEDURE  PictSizer (dPointer: Ptr; nextHunk: Integer);

BEGIN
    gPictSize := gPictSize + nextHunk;
END;


    { Routine to find out how much disk space will be required to save the data.
        This does not call the Inherited DoNeedDiskSpace since we don't support
        printing info here.  The routine will replace the PutPicProc of the port
        with our PictSizer routine.  When the picture is created here, no bytes
        will actually be allocated or saved, we will just watch it go by and
        save off the size in the global variable.  That value is returned
        as the expected document size. }
PROCEDURE TFracAppDocument.DoNeedDiskSpace(VAR dataForkBytes,
            rsrcForkBytes: LONGINT);   OVERRIDE;

VAR        picPort:            GrafPtr;
            currDevice:        GDHandle;
            currPort:            GrafPtr;
            newGrafs:            CQDProcs;
            oldProcs:            QDProcsPtr;        { bug in include files, CGrafPort has QDProcs *** }

BEGIN
    { Create a picture Item itself, by opening the picture and doing the CopyBits
        operation to the same port.  That picture will then be packed using the
        normal packing operation of the Mac.  That block is then the data to be
        written to the file. }

    currDevice := GetGDevice;                                { save off current one. }
    GetPort (currPort);

    SetGDevice (fDrawingDevice);                            { set to ours for drawing in it. }
    picPort := GrafPtr (fDrawingPort);                    { the pointer to our port. }
    SetPort (picPort);                                            { set there to do pict saving. }

        { Save the pointer to the current CGrafProcs }
    oldProcs := thePort^.grafProcs;

        { Set our GrafProc record up to have the standard pieces. }
    SetStdCProcs(newGrafs);

        { Change the port to use those GrafProcs instead. }
    thePort^.grafProcs := @newGrafs;

        { We are in our offscreen port.  Change the GrafProc pointer for picture saving. }
    newGrafs.putPicProc := @PictSizer;

        { Init the size of the pict we are going to save.  Start with picture header. }
    gPictSize := SIZEOF (Picture);

        { The current gDevice is our offscreen device.  Now go ahead and open the picture
            and build it in RAM.  We would have done this by slices before, but the newer
            systems have a patch for playing back pictures that minimize the RAM hit, so
            we don't have to worry about the full screen CopyBits here. }
    WITH  picPort^  DO BEGIN
        gPictHandle := OpenPicture (portRect);

                { copy all of the image to itself, in an open picture it saves the bits. }
            CopyBits (portBits, portBits, portRect, portRect, srcCopy, NIL);

        ClosePicture;                        { the picture is created, and packed. }
    END;        { with picPort^ }


        { Done saving the size of the picture itself.  Now set the GrafProcs back to normal. }
    thePort^.grafProcs := oldProcs;

        { Dispose the pict handle, we didn't actually make anything there. }
    KillPicture (gPictHandle);
    gPictHandle := NIL;

    { Set the drawing device back where it belongs, in case of error, we get right device. }
    SetGDevice (currDevice);                                    { set back to system for normal. }
    SetPort (currPort);

    { The picture has been sized.  Now add that in to the total size the file will use on
        disk, include the header for the file, plus the number of bytes in actual PICT. }
    dataForkBytes := dataForkBytes + gPictSize + kPICTHeaderSize;
END;        { DoNeedDiskSpace }


    { This routine will save the current image as it is created.  As the data requests
        go by that data will be written to the file.  The data is being created by the
        OpenPicture/CopyBits in DoWrite, this is the bottleneck for that operation.
        Any errors found while doing this will make us skip any further requests
        to write data to the disk.  No memory is allocated.   Communication with
        DoWrite is done through globals, since bottlenecks must be at the main
        level.  The bottleneck must also keep track of how many bytes are written,
        so that the header on the picture can be fixed up to be correct.  This must
        be done to avoid creating bogus pictures.  The picSize field of the handle
        must be updated continuously so that when the picture is done, the ClosePicture
        can create a valid picture.  The check for the NIL handle is to handle the
        problem of when the OpenPicture is called.  The proc gets called before
        the handle is valid.  Be very careful of these bottleneck things, it is
        easy to run into problems that are very hard to figure out.  QuickDraw
        has no facilities to give you info when things go wrong so it makes it
        a bit tougher. }
PROCEDURE  PictWriter (dPointer: Ptr; nextHunk: Integer);

VAR    longHunk:    LongInt;

BEGIN
    IF gPictError = noErr THEN  BEGIN
        longHunk := nextHunk;
        gPictError := FSWrite(gPictRefNum, longHunk, dPointer);
        gPictSize := gPictSize + longHunk;
        IF gPictHandle <> NIL THEN  gPictHandle^^.picSize := LoWord (gPictSize);
    END;
END;


    { Write the data calculated into the document to the file.  This will make it a real
        PICT file.  It writes the header first, then the PICT data.  This is so that it
        will still be a normal PICT file and can be used by other programs.
        The file will be saved using QuickDraw Bottlenecks for the PutPicProc.
        As the data requests go by, they will be written to the file, using the
        PictWriter routine. }
PROCEDURE TFracAppDocument.DoWrite(aRefNum: INTEGER; makingCopy: BOOLEAN);
            OVERRIDE;

VAR        recSize:            LongInt;
            fi:                     FailInfo;
            picPort:            GrafPtr;
            currDevice:        GDHandle;
            currPort:            GrafPtr;
            newGrafs:            CQDProcs;
            oldProcs:            QDProcsPtr;        { bug in include files, CGrafPort has QDProcs *** }

    PROCEDURE DeathWrite (error: OSErr; message: LONGINT);
    BEGIN
        IF gPictHandle <> NIL THEN      KillPicture (gPictHandle);
        gPictHandle := NIL;

        thePort^.grafProcs := oldProcs;
        SetGDevice (currDevice);                { set back to system for normal. }
        SetPort (currPort);
    END;

BEGIN
        { We have legit data in our document, set the mark in the file to be at the front. }
    FailOSErr ( SetFPos (aRefNum, fsFromStart, 0) );

        { Write the FracHeader to the file, it includes the pertinent details about
            the fractal including the global state for it. }
    recSize := SIZEOF (FracRecord);                           { our header on fractal files. }
    FailOSErr ( FSWrite (aRefNum, recSize, @fFracHeader) );

        { Now we need to write the picture data itself out to the file, after we set the
            mark to be after the entire header.  Make sure the file is that big before we do it.
            Included in this set is the header of the picture itself, the 10 bytes that
            include the rectangle.  Those bytes will be updated after the picture is
            written. }
    FailOSErr ( SetEOF (aRefNum, kPICTHeaderSize+SIZEOF (Picture) ) );
    FailOSErr ( SetFPos (aRefNum, fsFromStart, kPICTHeaderSize+SIZEOF (Picture) ) );

        { The file is all set up to go.  We now want to replace the QuickDraw bottleneck
            and create the actual Picture data. }
    currDevice := GetGDevice;                                { save off current one. }
    GetPort (currPort);

        { If the write of the picture header fails, we want to dispose the handle allocated. }
    CatchFailures(fi, DeathWrite);

        { Move over to the offscreen port/device. }
    SetGDevice (fDrawingDevice);                            { set to ours for drawing in it. }
    picPort := GrafPtr (fDrawingPort);                    { the pointer to our port. }
    SetPort (picPort);                                            { set there to do pict saving. }

        { Save the pointer to the current CGrafProcs }
    oldProcs := thePort^.grafProcs;

        { Set our GrafProc record up to have the standard pieces. }
    SetStdCProcs(newGrafs);

        { Change the port to use those GrafProcs instead. }
    thePort^.grafProcs := @newGrafs;

        { We are in our offscreen port.  Change the GrafProc pointer for picture saving. }
    newGrafs.putPicProc := @PictWriter;

        { Tell PictWriter what file to write to, and start the pic size including the
            picture header.  Start all the pieces off the right way. }
    gPictRefNum := aRefNum;
    gPictSize := SIZEOF(Picture);
    gPictError := noErr;
    gPictHandle := NIL;

        { Actually open the picture and do the CopyBits in order to process the picture.
            The data will be written by PictWriter as it is called by QuickDraw. }
    WITH  picPort^  DO BEGIN
        gPictHandle := OpenPicture (portRect);
            ClipRect(portRect);            { Make it a happier picture. }

                { copy all of the image to itself, in an open picture it saves the bits. }
            CopyBits (portBits, portBits, portRect, portRect, srcCopy, NIL);

        ClosePicture;                        { the picture is created, and packed. }
    END;        { with picPort^ }

        { Now check for errors during the write operation.  The gPictError field will be
            nonzero if we failed during the operation. }
    FailOSErr (gPictError);

        { Move back to front of file and write the valid picture info to file. }
    FailOSErr ( SetFPos (aRefNum, fsFromStart, kPICTHeaderSize) );
    recSize := SIZEOF(Picture);
    FailOSErr (FSWrite(aRefNum, recSize, Ptr(gPictHandle^)));

        { Done saving the data of the picture itself.  Now set the GrafProcs back to normal. }
    thePort^.grafProcs := oldProcs;

        { Dispose the pict handle, we didn't actually make anything there. }
    KillPicture (gPictHandle);
    gPictHandle := NIL;

        { Set the drawing device back where it belongs, in case of error, we get right device. }
    SetGDevice (currDevice);                                    { set back to system for normal. }
    SetPort (currPort);

        { If we lived through it, clear error handler. }
    Success (fi);
END;            { TFracAppDocument.DoWrite }


    { The bottleneck routine to read the picture from the disk.  This will read the
        data required, and pass it along to the unpacker.  This makes it possible to
        avoid using any RAM for the actual reading part, as it is being played back
        into the offscreen device.  Error handling is somewhat tricky, since we
        need to force the picture to finish, and there isn't a really good way to
        do this.  The desired attempt here is to pass back a picture is finished
        opcode ($00FF) so we can get back to our code to handle the error.  This is
        better than no error recovery, but is not guaranteed to work. }
PROCEDURE  PictReader (dPointer: Ptr; nextHunk: Integer);

VAR    longHunk:    LongInt;
        I:                Integer;

BEGIN
    IF gPictError = noErr THEN  BEGIN
        longHunk := nextHunk;
        gPictError := FSRead(gPictRefNum, longHunk, dPointer);
    END
    ELSE            { handle the error situation by passing back $00FF as the data.? }
        FOR I := 1 to nextHunk  DO BEGIN
            IF ODD (I) THEN  dPointer^ := $00
            ELSE  dPointer^ := $FF;
            dPointer := PTR (ORD4(dPointer) + 1);
        END;
END;


    { Routine to read the data from the data fork of the file into our document so it
        can be displayed.  The quickdraw bottleneck will be replaced with the
        PictReader routine, making it read the data from the disk as the picture
        requests more data.  This obviates the need for an extra handle that is
        used to play back the picture.  This is done since that extra handle can
        be on the order of 100K, memory we may not have available. }
PROCEDURE TFracAppDocument.DoRead(aRefNum: INTEGER; rsrcExists,
                                                  forPrinting: BOOLEAN);  OVERRIDE;

VAR        recSize:            LongInt;
            fi:                     FailInfo;
            currDevice:        GDHandle;
            currPort:            GrafPtr;
            newGrafs:            CQDProcs;
            oldProcs:            QDProcsPtr;        { bug in include files, CGrafPort has QDProcs *** }

    PROCEDURE DeathRead (error: OSErr; message: LONGINT);
    BEGIN
        IF gPictHandle <> NIL THEN  KillPicture (gPictHandle);
        gPictHandle := NIL;
    END;

BEGIN
        { The file is open already, we just have to read the data out of it.  The first thing
            to read is the header we use to describe a fractal.  If we get an error
            here we need to split since we should always have at least a header.  The fractal
            header is the global state for the document.  We just read it into the record
            and use it from there. }
    FailOSErr ( SetFPos (aRefNum, fsFromStart, 0) );    { starts at first byte of file. }
    recSize := SIZEOF (FracRecord);                                   { size of header on fractal files. }
    FailOSErr ( FSRead (aRefNum, recSize, @fFracHeader) );

        { We have the header for the PICT file.  Now we need to be sure that it is a fractal
            document, and not something we can't use.  Check the header to be sure, and if
            not right, error out with a good alert message (using a standard MacApp errcode). }
    IF fFracHeader.fType <> kSignature  THEN  FailOSErr (errNotMyType);

        { We have the data from the header, go ahead and set up an offscreen world for this
            document, using the header rectangle. }
    BuildOffWorld (fFracHeader.calcRect);

        { Make sure the file position is right at the start of the picture in the file. }
    FailOSErr ( SetFPos (aRefNum, fsFromStart, kPICTHeaderSize) );

        { Allocate a small handle that will be used as the Pict handle for drawing from
            the disk.  This is just the picture header. }
    gPictHandle := PicHandle (NewHandle (SIZEOF(Picture)));
    FailNil (gPictHandle);

        { If the read of the picture header fails, we want to dispose the handle allocated. }
    CatchFailures(fi, DeathRead);

        { Tell PictReader what file to read from. }
    gPictRefNum := aRefNum;
    gPictError := noErr;

        { Now fill in the picture header itself, using the data from the disk. }
    recSize := SIZEOF(Picture);
    gPictError := FSRead(aRefNum, recSize, Ptr (gPictHandle^));
    FailOSErr (gPictError);

        { That is the only call we can╒t recover from immediately, the rest of the
            routine is not easy to recover from, so we won╒t go through DeathRead. }
    Success (fi);

        { The file position is right at the beginning of the picture data, so we can just
            install the bottleneck and call DrawPicture to fill our offscreen gDevice
            with the data that was saved.  Set to that port and gDevice for playback. }
    currDevice := GetGDevice;                        { save current to get back. }
    GetPort (currPort);

    SetGDevice (fDrawingDevice);
    SetPort (GrafPtr(fDrawingPort));

        { Save the pointer to the current CGrafProcs }
    oldProcs := thePort^.grafProcs;

        { Set our GrafProc record up to have the standard pieces. }
    SetStdCProcs(newGrafs);

        { Change the port to use those GrafProcs instead. }
    thePort^.grafProcs := @newGrafs;

        { We are in our offscreen port.  Change the GrafProc pointer for picture reading. }
    newGrafs.getPicProc := @PictReader;

        { Now we have the buffer and the offscreen port.  We can draw the picture that
            will be read out of the file into this port in order to init the port for later use in
            updating the window.  We are already set to draw in the offscreen port.  Do the
            DrawPicture to have PictReader read the data out of the file while it is being
            played into the offscreen Port. }
    DrawPicture(gPictHandle, gPictHandle^^.picFrame);

        { Done reading the data of the picture itself.  Now set the GrafProcs back to normal. }
    thePort^.grafProcs := oldProcs;

        { Bag the handle we made for playing back the picture. }
    KillPicture (gPictHandle);
    gPictHandle := NIL;

        { Set back to the normal drawing environment. }
    SetGDevice (currDevice);
    SetPort (currPort);

        { If we had an error while reading the data, we must error out. }
    FailOSErr (gPictError);
END;        { TFracAppDocument.DoRead }


    { This is typically used in a Revert case which is not really meaningful here, but
        the structure is the same so we use it anyway.  Frees the data associated with
        a document, that is strictly program data, not MacApp data. }
PROCEDURE TFracAppDocument.FreeData; OVERRIDE;

BEGIN
        { Kill the bits for the offscreen bitMap if they were allocated. }
    IF fBigBuff <> NIL  THEN  DisposPtr (fBigBuff);
        { Close the port: remove from portList, kill visRgn and clipRgn, kill the penPixPat
            and fill PixPat and back PixPat, kill PixMap handle, kill grafVars handle. }
    IF fDrawingPort <> NIL  THEN  BEGIN
        CloseCPort (fDrawingPort);
        DisposPtr (Ptr (fDrawingPort) );
    END;
        { DisposGDevice does: kills the ITable, kills Cursor expanded data and mask if
            nonzero, calls DisposPixMap if gdPMap is nonzero, then disposes the gDevice
            handle itself.  DisposPixMap kills the colorTable and the pixMap record. }
    IF fDrawingDevice <> NIL  THEN DisposGDevice (fDrawingDevice);
END;    { TFracAppDocument.FreeData }


    { Free method for the documents themselves.  We need to override so that we
        can throw away the data object that was read in from the disk if it exists.
        Also chuck the gDevice and port used for the document data. }
PROCEDURE TFracAppDocument.Free; OVERRIDE;

BEGIN
    FreeData;

    INHERITED Free;
END;    { TFracAppDocument.Free }


    { The procedure to do the idle time processing in the document.  This will do the
        entire fractal calculation so as to be able to do it in the background.  It
        does it one pixel at a time to avoid any hit on performance for the
        foreground application.  This is called in response to the DoIdle for the
        application.  The fIdlePriority is not set for this method, so it won't get
        time except when the application calls specifically.  It is done this way
        since otherwise the target chain would need to have each document in
        the list, which is not desireable for other event handling.  Notably the
        time keeper in here is not too accurate.  Each pixel takes less than a
        tick to calculate, making it a bit tougher.  A way to make it more
        accurate would be to figure out the maximum time for a full black
        document, and divide by the number of pixels in the screen and the
        number of loops.  That number (in microseconds) could be added each
        time through the calculation loop to give a more accurate timestamp.
        This would be wrong if the clock changes, so perhaps it should use the
        low memory TimeDBRA value as units instead.
        This is left as an exercise for the reader. }
PROCEDURE  TFracAppDocument.CalcCity;

CONST    M                = 100;                    { this decides what 'infinity' is.  If value less than this, loop. }
            K                = kNumColors;        { number of colors to choose from. Also iterations times.  This
                                                            is 195 to match the clut created for it. }
            BlackPen    = 255;                    { entry in our modified color table for black. }

VAR        currTime:            LongInt;        { temp var for time check. }

            x,y,x1,y1:            Extended;        { for interim values of current point. }
            Po,Qo:                Extended;

            kol:                    Integer;        { color we are currently on. }
            r:                        Extended;        { 'distance' from root. }
            currDevice:        GDHandle;        { current gDevice handle, so we can get back there. }
            currPort:            GrafPtr;
            drawRect:            Rect;            { for updating the screen as we calculate. }

BEGIN
        { Calculate the fractal as we go.  Do next pixel here, based on the state saved
            in the document object.  When done, the variables are updated to go to the
            next location to do.  It sets the pixel in the offscreen port to be whatever
            we calculate it to be.  The buffer will be copied to the screen at update time.
            The global state is saved in the FracHeader record in the document object.
            That state is saved across the use of a document, so it will always be right. }

        { If we are done, or not started, we can split. }
    IF  fFracHeader.done THEN  Exit(CalcCity);

    currDevice := GetGDevice;                    { save off current one. }
    GetPort (currPort);

    SetGDevice (fDrawingDevice);                { set to ours for drawing in it. }
    SetPort (GrafPtr(fDrawingPort));        { draw in offscreen guy. }

    { Now do the calculation to determine the color of the pixel at the
        current location.  Uses the header saved state. }

    With  fFracHeader  DO BEGIN
(*        x := realMin + curCol * deltaP;                    { Use these for a Julia set calculation. }
        y := imagMin + curRow * deltaQ;
        kol := 0;
        Po := -0.39054;
        Qo := 0.58679;
*)
        Po := realMin + curCol * deltaP;                { next starting point  }
        Qo := imagMin + curRow * deltaQ;
        kol := 0;
        x := 0;                                                        { Mandel set starts with 0 always. }
        y := 0;                                                        { For Julia set you start with previous number. }
    END;        { With }

    REPEAT
        { the following is for y = X^2 + C for imaginary numbers.
        pt1 = x + yi,  C = Po + Qoi,  in pt2 := pt1^2 + C  }

        x1 := x*x - y*y + Po;
        y1 :=2*x*y + Qo;

        kol := kol + 1;
        x := x1;  y := y1;

        r := x1*x1 + y1*y1;
    UNTIL  (r > M) OR (kol > K);                { Until 'distance' > our infinity, or out of colors. }

    IF kol <= K  THEN                                { r must be > M. }
        fDrawingPort^.fgColor := kol            { set the color }
    ELSE                                                    { must be kol > K, ran out of colors. }
        fDrawingPort^.fgColor := BlackPen;

        { Move to the pixel we calculated for, then draw the pixel in right color.  This
            could be done by setting the bytes in pixel map directly, since we own the
            PixMap and the buffer. }
    MoveTo (fFracHeader.curCol, fFracHeader.curRow);
    Line (0,0);                                            { draw that 'pixel' in the right color }


        { up the counters to the next pixel location to do. }
    WITH  fFracHeader  DO BEGIN
        curCol := curCol + 1;                                    { up the column count. }
        drawRect := thePort^.portRect;                    { in case we finished a line. }
        IF curCol >= plotWidth  THEN  BEGIN            { did we run off end of row? }
                { Have the line just calculated drawn to window. }
            drawRect.top := curRow;
            drawRect.bottom := curRow+1;

            curCol := 0;                                            { start on the next row. }
            curRow := curRow + 1;                            { and up the counter of the next row to do. }
        END;  { start at next row. }

    END;  { with  fFracHeader }

        { Check if we are done, and if so, set the flag to stop calculations.  Set the
            elapsed time counter in the header. }
    IF fFracHeader.curRow >= fFracHeader.plotHeight  THEN  BEGIN
        fFracHeader.done := TRUE;
        GetDateTime(currTime);
        fFracHeader.elapsedTime := currTime - fStartTime;
    END;

    IF NOT EqualRect (thePort^.portRect, drawRect) THEN
        fFracAppView.InvalidRect (drawRect);

    SetGDevice (currDevice);                                { set back to main for normal drawing. }
    SetPort (currPort);

    { Now we have changed another point in the document.  We need to mark it as
        changed so we can save the document. }
    fChangeCount := fChangeCount + 1;

END;        { TFracAppDocument.DoIdle }


{-------------------------------  View  -------------------------------}

    { Initialize the view, basically set up the view object and clear the selection. }
PROCEDURE     TFracAppView.IFracAppView (itsDocument: TFracAppDocument;
        sizeOfView: Rect);

BEGIN
    fSelectionRect := gZeroRect;                    { no selection to start with. }
    fFracAppDocument := itsDocument;        { save off parent document for convenience. }

        { This view will be the full size of the screen since we have an offscreen
            bitMap as the view.  This will be clipped to fit the frame of the window.
            There is no parent view, and the horizontal and vertical are fixed.  The
            selection is to be shown, and is initially off. }
    IView(NIL, itsDocument, sizeOfView, sizeFixed, sizeFixed, TRUE, hlOff);

END;        { TFracAppView.IFracAppView }


    { We are going to map our full blown fractal into a sub universe with lesser
            colors.  We need to do a linear map of the indices we get to whatever
            is in the color table.  This will make zebra fractals.   This mapping
            is only done for devices that don╒t have enough colors to handle our
            normal fractals. }

FUNCTION SearchLips(VAR RGB: RGBColor;  VAR result: LongInt) : Boolean;

VAR        I:                        Integer;
            theIndex:            Integer;

BEGIN
    SearchLips := True;        { always say we hit. }

    { Start the map by finding the input color in the offscreen color table.  Using
        the global color table makes it easy to get the right colors. }

    FOR  I := 0 to gOurColors^^.ctSize  DO
        IF    (gOurColors^^.ctTable[I].rgb.red = RGB.red)  &
            (gOurColors^^.ctTable [I].rgb.green = RGB.green)  &
            (gOurColors^^.ctTable [I].rgb.blue = RGB.blue)  THEN  BEGIN
                theIndex := I;
                Leave;         { Skip out of the loop, we found it. }
            END;        { Found index in offscreen table that is the input color. }

    { Now theIndex has the index value corresponding to the color we are trying to
        match.  Perform the MOD operation on it to get into the range needed for
        the current gDevice.  (If you do a DIV instead, you will get a picture without
        bands, but with the available colors mapped across the range nicely instead.
        Multiple bands will be one color.)
        This MOD uses ctSize+1 since ctSize is a zero-based number, and the MOD
        needs to be for the number of actual colors available. }
    result := theIndex MOD (GetGDevice^^.gdPMap^^.pmTable^^.ctSize+1);

END;    { SearchLips }


    { Our routine to do the drawing of the fractal.  This is the display routine
        to take the data out of the offscreen buffer and whip it up to the window,
        as the current view. The fractal is full screen size, clips without
        scaling into the window.  It draws to any device connected to the machine
        and uses fast updates or search procs where needed, for the enough colors
        or not enough colors cases. }
PROCEDURE TFracAppView.Draw(area: Rect); OVERRIDE;

    PROCEDURE  SetUp (curGar: TGarDevice);

    BEGIN
        curGar.SetUpColorMap;
    END;

    PROCEDURE  Remove (curGar: TGarDevice);

    BEGIN
        curGar.RemoveColorMap;
    END;


BEGIN
    { Make the ctSeed of both the source gDevice and destination match so there is no
        remapping of the colors that we are using.  The colors are close enough together
        that even 5 bit resolution provided for the mapping procedure is not sufficient.
        The primary reason to do this is to make the blitting faster, since no color
        mapping is done.  This gives the fastest updates possible, since color quickdraw
        does no color mapping, it just moves bytes.  This will only work properly if we
        have enough colors to do it. If we don╒t have enough, we will set up the color
        search procs to do the mapping required.  We will also watch the ctSeed of the
        device to see if we need to set our colors.  If the ctSeed changes, the color
        table changed, so we need to reset our colors useage.  In order to do this for
        each gDevice we will use our TList to make it easy.  We also save the current
        seed for each device before we update to them, then restore that seed after
        the drawing.  This makes the drawing fast still, but is a more mellow use of the
        ctSeeds. }

    gGarList.Each (SetUp);

    CopyBits ( GrafPtr(fFracAppDocument.fDrawingPort)^.portBits,
            thePort^.portBits, area, area, srcCopy, Nil);

    gGarList.Each (Remove);
END;        { TFracAppView.Draw }


    { Handle the menu choice for New Fractal out of the Fractal Menu.  This makes a new
        Fractal based on the current selection.  It does it by calling on the application
        object to make a new document.  The communication to the DoInitialState is
        through the global variables. }
FUNCTION TFracAppView.DoMenuCommand(aCmdNumber: CmdNumber): TCommand;  OVERRIDE;

VAR        oldDeltaP,
            oldDeltaQ,
            oldRealMin,
            oldImagMin:    Extended;                    { for figuring new fractal area. }

BEGIN
    { Assume that we have no command to return, since none of our commands currently
        change the document. }
    DoMenuCommand := gNoChanges;            { no command object returned. }

    { Case off on the various menus.  Currently we have the new fractal item.
        Any out of that list are handled by Mr. MacApp and we pass it on. }
    CASE  aCmdNumber  OF

        kNewFractal:
            { If the option chosen was the New Fractal item, then we need to start
                up a fresh one based on the selection rectangle.  This new fractal is
                based on parts of the old one, since it is
                a zoom in operation.  We make a new document/window/view
                as if it were a New operation.  We then change the fields we need to in
                that document to make it start calculating based on the selection from
                the current view. }

            BEGIN
                { Make a new document and initialize it to the base state.  If we fail in
                    opening it, we won't return here, the failure handler will kill it.  We
                    have nothing else to dispose of, so we don't make a CatchSignals here.
                    This will come out of permanent memory.  The aCmdNumber is so that
                    the new document knows it came from a zoom in operation.  Since this
                    is somewhat funky, we communicate to the other part of the program
                    with the global variables.  If nonzero, the code that makes a
                    new document will know to use these numbers in order to do the zoom.
                    This is less than completely desireable, but there are no good places
                    to override in order to get both the selection rectangle and the new
                    document objects. }

                    { The basic fractal has been set up.  We now need to change the calculation
                        area based on the current selection, in order to effect the zoom in. }
                WITH  fFracAppDocument.fFracHeader DO BEGIN
                    oldDeltaP := deltaP;                            { from SELF, the old document. }
                    oldDeltaQ := deltaQ;
                    oldRealMin := realMin;
                    oldImagMin := imagMin;
                END;

                { calculate new min/max for real and imaginary parts based on how far
                    into the old fractal plane we were.  This is an extended calculation
                    since our plane is in extendeds.  We get the new locations of min and
                    max, and save them off.  We reset the deltaP or Q with SetUpConstants,
                    in order to force a 1:1 ratio, but we need all sides to determine
                    which one to force.  }
                gRealMin := oldRealMin + oldDeltaP * fSelectionRect.left;
                gImagMin := oldImagMin + oldDeltaQ * fSelectionRect.top;
                gRealMax := oldRealMin + oldDeltaP * fSelectionRect.right;
                gImagMax := oldImagMin + oldDeltaQ * fSelectionRect.bottom;

                gApplication.OpenNew (aCmdNumber);
            END;

        OTHERWISE
            DoMenuCommand := INHERITED  DoMenuCommand (aCmdNumber);    { next guy in chain. }
    END;        { CASE on aCmdNumber }

END;    { TFracAppView.DoMenuCommand }


    { Set up the New Fractal menus choice in Fractal Menu, based on selection. }
PROCEDURE TFracAppView.DoSetupMenus;  OVERRIDE;

BEGIN
    INHERITED DoSetupMenus;                            { Do mainline stuff first. }

        { If we have a non-zero selection, then we can enable the menu item to use
            it as the new fractal dimensions for this document. }
    Enable (kNewFractal, NOT EmptyRect (fSelectionRect));
END;    { TFracAppView.DoSetupMenus }


    { The way to handle mouse events in the content region of the view.  This will
        pass back the command object to handle tracking the mouse and creating a
        new selection in preparation for making a new fractal. }
FUNCTION  TFracAppView.DoMouseCommand(VAR downLocalPoint: Point;
                        VAR info: EventInfo;  VAR hysteresis: Point): TCommand;    OVERRIDE;

VAR        tracker:    TAreaSelector;

BEGIN
    New(tracker);                                        { make a new command object. }
    FailNIL(tracker);                                    { no memory, trash out. }
    tracker.IAreaSelector(SELF, downLocalPoint); { Initialize the command object. }
    DoMouseCommand := tracker;                { return it for later use. }
END;        { TFracAppView.DoMouseCommand }


    { Highlight the current selection rectangle if there is one.  This is drawn in scrCopy
        mode to make it stand out better when it is a final selection.  XOR is used for
        the rubberband, until mouseUp. }
PROCEDURE TFracAppView.DoHighLightSelection(fromHL, toHL: HLState); OVERRIDE;

VAR        selPatHandle:    PatHandle;

BEGIN
    IF toHL = hlOn THEN  BEGIN
        selPatHandle := GetPattern(kSelPattern);    { get the pattern we use. }
        IF selPatHandle <> NIL  THEN                         { If pattern available, use it. }
            PenPat (selPatHandle^^);                            { set pen pattern to our selection kind. }
        PenMode(srcCopy);                                        { copy mode on pattern selection. }

            { We have a selection, so go ahead and draw the selection rectangle. }
        FrameRect (fSelectionRect);                        { outline the frame of selection. }
    END;        { highlight turned on. }

        { Turning off the highlight, we need to remove the traces of the selection.
            To do this, redraw that rectangle. }
    IF toHL = hlOff THEN   Draw (fSelectionRect);    { ReDraw it to clear selection. }
END;        { TFracAppView.DoHighlightSelection }


{-------------------------------  Command  -------------------------------}

    { Initialize the selector object itself.  Sets up the normal fields. }
PROCEDURE TAreaSelector.IAreaSelector(ownerView: TFracAppView; startPt: Point);

BEGIN
    ICommand(cMouseCommand);                    { initialize normal parts of command }

    fCausesChange := FALSE;                            { just selection, not changing document. }
    fCanUndo := FALSE;                                    { therefore, no Undo of no change. }
    fConstrainsMouse := TRUE;                        { do the constrain to match to screen. }
    fOwnerView := ownerView;                        { save the view for use in tracking. }
END;    { TAreaSelector.IAreaSelector }


    { Track the mouse while the button is down.  This is overridden so we can leave
        the command object as not having changed, ie. so we can pass back the
        gNoChanges as the last step since this is not an undoable operation.  It
        doesn't change the view, so we don't need to DoIt or Commit. }
FUNCTION  TAreaSelector.TrackMouse(aTrackPhase: TrackPhase;
                        VAR anchorPoint, previousPoint, nextPoint: Point;
                        mouseDidMove: BOOLEAN): TCommand;  OVERRIDE;

VAR        selPatHandle:        PatHandle;

BEGIN
    TrackMouse := SELF;                                { Assume we are not in release phase. }

    CASE aTrackPhase OF
        trackPress:
        BEGIN
            fOwnerView.DoHighLightSelection (hlOn, hlOff);        { turn off old selection if any. }
            fOwnerView.fSelectionRect := gZeroRect;                { clear rect, there isn't one. }
        END;

        trackRelease:
        BEGIN
            Pt2Rect(anchorPoint, nextPoint, fOwnerView.fSelectionRect);
            fOwnerView.DoHighlightSelection (hlOff, hlOn);        { leave on selection. }
            TrackMouse := gNoChanges;
        END;
    END;    { Case on aTrackPhase }
END;    { TAreaSelector.TrackMouse }


    { Track the mouse giving the feedback of a different rectangle kind.  This is so
        we can use the selection pattern to give a preferred rectangle.  The selection
        pattern comes out of temporary memory so as to not fail needlessly. }
PROCEDURE TAreaSelector.TrackFeedback(anchorPoint, nextPoint: Point;
                        turnItOn, mouseDidMove: BOOLEAN);  OVERRIDE;

VAR        selBoy:                    Rect;
            selPatHandle:        PatHandle;

BEGIN
    IF mouseDidMove THEN
        BEGIN {the pen is already in patXOR mode, black, one wide}
            selPatHandle := GetPattern(kSelPattern);    { get the pattern we use. }
            IF selPatHandle <> NIL  THEN                        { use our pattern if available. }
                PenPat (selPatHandle^^);                            { set pen pattern to our selection kind. }

            Pt2Rect(anchorPoint, nextPoint, selBoy);
            FrameRect(selBoy);
        END;
END;    { TAreaSelector.TrackFeedback }


    { Constrain the mouse to a rectangle that is the same proportion as the screen, so
        we can make the selection match better without having to guess at the length
        or width, or scaling the chosen rect to fit the screen.  Small piece chosen will
        blow up to fit easily.  This will make it easier to choose a selection that
        gives a 1:1 aspect ratio.  This also chooses which direction the mouse has
        moved, deciding which is larger in order to decide the direction to constrain. }
PROCEDURE TAreaSelector.TrackConstrain(anchorPoint, previousPoint: Point;
                            VAR nextPoint: Point);  OVERRIDE;

VAR        newWidth, newHeight:        LongInt;
            mouseRatio, plotRatio:        Real;
            constrainRect:                    Rect;

    PROCEDURE  ChangeWidth;
    BEGIN
        WITH  fOwnerView.fFracAppDocument.fFracHeader  DO BEGIN
                { Get the new width as a positive number, a displacement that is constrained. }
            newWidth := ABS (nextPoint.v - anchorPoint.v) * plotWidth DIV plotHeight;
                { Decide which quadrant we are in, moving the right direction. }
            IF nextPoint.h < anchorPoint.h  THEN newWidth := -newWidth;
                { Actually change the final point to pass back. }
            nextPoint.h := anchorPoint.h + newWidth;                        { add offset to get new pt. }
        END;
    END;

    PROCEDURE  ChangeHeight;
    BEGIN
        WITH  fOwnerView.fFracAppDocument.fFracHeader  DO BEGIN
            newHeight := ABS (nextPoint.h - anchorPoint.h) * plotHeight DIV plotWidth;
            IF nextPoint.v < anchorPoint.v  THEN newHeight := -newHeight;
            nextPoint.v := anchorPoint.v + newHeight;                    { add offset to get new pt. }
        END;
    END;

    PROCEDURE  PinPoint;                    { Pin the rectangle to the edge of the document. }
    BEGIN
        WITH  fOwnerView.fFracAppDocument.fFracHeader  DO BEGIN
            SetRect(constrainRect, 0, 0, plotWidth, plotHeight);
            nextPoint := Point (PinRect(constrainRect, nextPoint));
        END;
    END;

BEGIN
    WITH  fOwnerView.fFracAppDocument.fFracHeader  DO BEGIN
        mouseRatio := ABS ((nextPoint.h - anchorPoint.h)/(nextPoint.v - anchorPoint.v));
        plotRatio := plotWidth/plotHeight;

            { The deltaX, deltaY can be thought of as a rect too.  If the ratio of sides on
                that rect (width/height) is greater than the ratio of width/height of the
                plot rectangle, then we need to grow the height of the rect.  If it is less,
                we need to grow the width.  This is a ratio of sides to decide which way
                to grow.  We grow to make the new rect still touch the mouse position.
                It can be thought of as the rectangle being thicker than tall wanting to
                grow the tall part in a constrained way, and the corollary for the width. }
        IF mouseRatio > plotRatio  THEN BEGIN        { constrain height to new value. }
                ChangeHeight;
                PinPoint;
                ChangeWidth;
            END
        ELSE        BEGIN        { constrain width to new value. }
                ChangeWidth;
                PinPoint;
                ChangeHeight;
            END;
    END;    { With }
END;    { TAreaSelector.TrackConstrain }


{-------------------------------  GarDevice  -------------------------------}

    { A routine to initialize all the GarDevice objects desired for the system.  This
        takes the info passed in and sets up the GarDevice object the right way.  It
        also adds it to the gGarList TList. }

PROCEDURE  TGarDevice.IGarDevice (OwnerGDevice: GDHandle);

BEGIN
    fDevice := OwnerGDevice;                        { Init the fields to keep track of device. }
    fColorTable := NIL;
    fOldSeed := 0;
    gGarList.InsertLast (SELF);                    { Add this guy into the TList. }
END;


    { A routine to pound the color table to be ours if there are enough colors available.
        This will use the clut resource used for documents to set up the color table to
        our nice prechosen set of colors.  If there aren't enough colors available to do
        the full job, we leave it alone, and let the Palette Manager do his thing.   Error
        handling here is done in a simple fashion.  If we have errors, we leave the
        fColorTable = NIL so that we don╒t change the colors.  We won╒t pass back
        an alert since it would be confusing and we don╒t have a good thing to say.
        On the SetEntries and protection, we
        don╒t check errors since they can only cause strange colors to be displayed,
        not a crash, and it is unclear how to handle errors there without being
        too obtuse. }
PROCEDURE TGarDevice.PoundColors;

VAR        offColorTable:        CTabHandle;
            I:                            Integer;
            Erry:                        OSErr;
            currDevice:            GDHandle;
            LocalColors:            CTabHandle;

BEGIN
    IF fColorTable <> NIL THEN  DisposCTable (fColorTable);
    fColorTable := NIL;

    LocalColors := fDevice^^.gdPMap^^.pmTable;            { for convenient use. }

        { If we have enough colors on this device, we can do our strangeness. }
    IF LocalColors^^.ctSize > kNumColors THEN BEGIN

            { Save a copy of the system color table in our object.  This table will be used when
                we need to restore the color table upon exit.  If there aren't enough colors for
                our funny business we have the handle to NIL to imply that we didn't change it. }
        offColorTable := LocalColors;
        Erry := HandToHand (Handle (offColorTable));    { copy it so we don╒t use actual system handle. }
        IF Erry <> noErr THEN Exit (PoundColors);            { If it couldn╒t be done, exit with NIL. }

        fColorTable := offColorTable;                            { Save it off into the GarDevice object. }

        currDevice := GetGDevice;                                { Save current state. }

            { Set to the current GarDevice }
        SetGDevice(fDevice);

            { We now need to set up the color table in the system to be the way we want it,
                so we can avoid problems with programs that use the Palette Manager.  This
                involves reserving all of the colors we use so that they won╒t be used by any
                other program (including the Menu Manager for the Apple), and protecting the
                entries so they cannot be changed by the Palette Manager or other programs.
                Before doing that we need to save the state of the world so we can put it
                back when done or switched out.  We will use the global color table that
                matches all the documents. }
            { SetEntries is zero based, so we actually set kNumColors+1, and so starting
                with 0 makes us do the right number of entries.  The CSpecArray we have
                to pass is also conveniently starting at zero, which is why it is done this way. }
        SetEntries(0, kNumColors+kNumPalette, gOurColors^^.ctTable);

        For I := 1 to kNumColors  DO
            ReserveEntry (I, TRUE);        { No one should use our animating colors. }

            { We changed the ctSeed now, so we need to save it off, so we know when the
                color table has changed for real. }
        fOldSeed := LocalColors^^.ctSeed;

            { Set back to where we started from. }
        SetGDevice(currDevice);

            { If we changed the main device, redraw the menu bar to make colors right. }
        IF fDevice = GetMainDevice  THEN DrawMenuBar;

    END;    { enough colors to make it worthwhile. }
END;    { PoundColors }


    { When we leave we need to restore the color table to its pristine form.  This is
        only done if we have changed the color table to our fancy set of colors.  We use
        the fColorTable handle as a boolean as well.  If it is NIL, we didn't have a
        saved color table to restore.  This routine will be called for each GarDevice in
        the TList.  Any errors that are run into here are ignored, since it is too late
        to fix them.  They will not be catastrophic, and in the worst case will munge
        up the colors in the color table as we exit.  Since we have the temporary
        memory available we should never have any error here in the first place. }
PROCEDURE TGarDevice.UnPoundColors;

VAR        I:                            Integer;
            currDevice:            GDHandle;

BEGIN
        { If we still have enough colors on this gDevice, we can restore the color table.  }
    IF fColorTable <> NIL THEN BEGIN

            { Save off the current device state. }
        currDevice := GetGDevice;

            { Set us to be on that gDevice. }
        SetGDevice(fDevice);

            { Set the color table back to what it was before we came in and took over.  This
                means setting the colors back to those we started with, and setting the
                useage back to normal. }
        For I := 1 to kNumColors  DO
            ReserveEntry (I, FALSE);

            { and reset the color table to the colors that the system was using. }
        SetEntries(0, kNumColors+kNumPalette, fColorTable^^.ctTable);

            { Set back to the device we started on. }
        SetGDevice(currDevice);

    END;    { Had some colors to restore. }
END;    { UnPoundColors }


    { If there are enough colors on this GarDevice and the check mark was set, we must
        rotate them colors around.  If this GarDevice has enough colors we do it,
        otherwise we skip it. If we have an error while trying to do this, we want to
        just skip it, since it is noncritical to the program.  If we use the normal
        error handler we will end up giving an alert each time this is called which
        is too many.  In addition, we will use temporary memory for the allocations,
        so it is virtually impossible for the memory allocations to fail here.  The
        memory used is returned at the end of the routine, so it is temporary. }
PROCEDURE TGarDevice.RotateColors;

VAR        newCTable:            CTabHandle;
            lastCSpec:            ColorSpec;
            I:                            Integer;
            Erry:                        OSErr;
            currDevice:            GDHandle;
            LocalColors:            CTabHandle;
            fi:                            FailInfo;

        { If we had a memory problem during Rotation we need to exit, setting things
            back to normal.  We also clear the Rotation flag, to avoid being called again.
            In order to give a better error message in the alert, we pass our own string
            description as the message field.  This will look up the STR# in our resource
            list to use as the message. }
    PROCEDURE DeathRotate (error: OSErr; message: LONGINT);

    BEGIN
        IF newCTable <> NIL  THEN  DisposCTable(newCTable);
        SetGDevice (currDevice);                        { Set device back to main, just in case. }
        gRotateOn := FALSE;                                { Turn rotation off. }
        Failure (error, kBadRotate);                    { give the right error string. }
    END;


BEGIN
        { Get handle to color table so we don't have to use With statements, but still have
            it dereferenced more effectively. }
    LocalColors := fDevice^^.gdPMap^^.pmTable;

        { Check the seed for this device and be sure it matches what we have saved.
            When the color depth is changed with an FKEY or by some other code behind
            our back, we get the chance to rotate the colors around, before we handle
            the update event.  In any case, for safety, we want to avoid rotating if the
            color table has changed since we last looked at it. }
    IF fOldSeed <> LocalColors^^.ctSeed THEN  Exit (RotateColors);

        { See if we have enough colors on the current device to do, do nothing if not. }
    IF LocalColors^^.ctSize > kNumColors  THEN  BEGIN

        currDevice := GetGDevice;                                            { Save current gDevice. }
        SetGDevice(fDevice);                                                    { Set to our current Gar.}

        CatchFailures(fi, DeathRotate);                                    { any failures, must be cleaned up. }

            { Get this device╒s color table and copy it temporarily.  If not enough memory
                just skip out since it is not catastrophic. }
        newCTable := LocalColors;                                            { Handle to this CTable. }
        Erry := HandToHand (Handle(newCTable));                        { Make copy of it. }
        IF Erry <> noErr THEN  newCTable := NIL;                        { on error, we should skip dispose. }
        FailOSErr (Erry);                                                            { If we had an error, exit. }

            { Move the colors we are going to use down to the zero position so it is easy
                to use SetEntries.  We are trashing the color table, but it is a copy.  }
        lastCSpec := newCTable^^.ctTable[1];                            { pull first one off. }
        BlockMove (@newCTable^^.ctTable[2], @newCTable^^.ctTable[1],
                (kNumColors) * SIZEOF (ColorSpec) );                    { copy all one entry down. }
        newCTable^^.ctTable[kNumColors] := lastCSpec;            { put last color back on front. }

            { Change the color table to new position. }
        SetEntries (0, kNumColors, newCTable^^.ctTable);
        FailOSErr (QDError);

        DisposCTable(newCTable);

            { Save the new seed, since we changed it. }
        fOldSeed := LocalColors^^.ctSeed;

        SetGDevice(currDevice);                                        { Set back to start. }

        Success (fi);
    END;    { enough colors on device to rotate. }
END;    { RotateColors }


    { The routine to set up for the CopyBits by changing the color table if needed, and
        to make the ctSeeds match for fast updates where possible, and to install the
        color search procs on devices where we don't have enough color.  Called for
        each GarDevice in our TList.  Save off the devices' seed value so we can put
        it back after our update. }
PROCEDURE  TGarDevice.SetUpColorMap;

VAR        currDevice:        GDHandle;
            LocalColors:        CTabHandle;

BEGIN
    currDevice := GetGDevice;                                { Save current device. }
    SetGDevice (fDevice);                                        { Set to this gDevice. }

    LocalColors := fDevice^^.gdPMap^^.pmTable;        { Handle to color table. }

        { Check if the color environment changed on this device, and if so, pound
            our colors into place there.  This handles changes in depth when we are
            not switched out (FKEYs). }
    IF (fOldSeed <> LocalColors^^.ctSeed) AND NOT gBackGround  THEN
        PoundColors;

        { During the update process we want to be as fast as possible, so for the
            CopyBits we want the ctSeeds to match.  This will save the current seed
            and restore it when we are done CopyBitsing. }
    fDrawSeed := LocalColors^^.ctSeed;

        { If we have enough colors on this device, then make the seeds match so we
            have a high speed update.  If there isn't enough colors, then set up the search
            proc so we get the happy MOD color mapping on this device.  If we have enough
            colors do the slightly naughty operation of changing the devices' seed to
            match all the documents.  This is only done in order to make fast updates on
            devices that have enough colors. }
    IF  LocalColors^^.ctSize > kNumColors  THEN
        LocalColors^^.ctSeed := gOurColors^^.ctSeed
    ELSE
        AddSearch (@SearchLips);                            { Add our search proc to that device. }

    SetGDevice (currDevice);                                    { Set back to starting device. }
END;    { SetUpColorMap }


    { A routine applied to each GarDevice to remove any color search procs we installed,
        and restore any seeds we may have changed in order to be speedy. }
PROCEDURE  TGarDevice.RemoveColorMap;

VAR        currDevice:        GDHandle;

BEGIN
    currDevice := GetGDevice;                                { Save current device. }
    SetGDevice (fDevice);                                        { Set to this gDevice. }

        { If there were, restore the seed on the device to what color QD wants it to be.
            If there were not enough colors on this device, remove the color mapping proc. }
    WITH  fDevice^^.gdPMap^^.pmTable^^  DO
        IF ctSize > kNumColors  THEN
            ctSeed := fDrawSeed                                { restore the seed value. }
        ELSE
            DelSearch (@SearchLips);                            { Remove our special color mapper. }

    SetGDevice (currDevice);                                    { Set back to starting device. }
END;    { RemoveColorMap }


{$POP}        { Restore the compiler state. }