Games of Daze/Infomagic - Games of Daze (Summer 1995) (Disc 1 of 2).iso/x2ftp/msdos/lang/mc302/microcad/microcad.doc

Text File | 1994-03-18 | 16KB | 411 lines

MICROCAD is a very small drawing program (less than 12k!)

It has commands for drawing/erasing/moving/copying such things as lines,
boxes, circles, arcs, graphical text and other drawings as "group" objects.
It also features a "display" mode, where it can be used as a simple viewer,
and includes an MCPRINT utility to print your drawings.

This is not intended as a serious drafting package, however it is useful as
a means of transmitting simple drawings via diskette, or modem. MICROCAD is
"free", and may be used and distributed without payment or royalty.

The complete MICRO-C source code to MICROCAD is available free of charge
from our BBS, and may prove useful to anyone wishing to experiment with a
drawing editor, or add support for other devices.

In its current form, MICROCAD requires a mouse, a VGA display (it works
at 640x480), and either an HP LASERJET or EPSON DOT-MATRIX printer. It
should be fairly easy to modify it for compatibility with other devices.


The MICROCAD command:
--------------------

The MICROCAD command has the following syntax:

   MICROCAD [drawing file] [F=font file] [/Display]

   [drawing file] is the name of a file containing a drawing that you
wish to edit. The extension '.DWG' is assumed. If you do not specify a
file name, MICROCAD assumes its default name MICROCAD.DWG. This default
drawing file normally contains a blank drawing, and is used only to
establish the default settings for the "S)etup" values.

   [font file] is the name of a file containing a character set font that
will be used to display any text in the drawing file. If you do not specify
a font file, The default MICROCAD.FNT is assumed.

   [/Display] causes MICROCAD to act as a viewer. The mouse is not
activated, the grid is disabled (even if it is turned on in the drawing),
and the drawing is displayed. Pressing any key will terminate the MICROCAD
at this point.

Mouse:
-----

MICROCAD uses only the LEFT and RIGHT mouse buttons, allowing it to be
used with either a two or three button pointing device.

When sitting at the top command level (no command text visible at the
top of the screen), the mouse buttons function as follows:

   LEFT   - Brings up the command menu at the top of the screen. Pressing
            the key corrsponding to a command will active that command.

   RIGHT  - Activates the last command that you executed. This is a useful
            way to perform multiple operations, such as drawing multiple
            box's etc.

Unless noted otherwise, the mouse buttons behave as follows once a command
has been activated:

   LEFT   - Performs an operation for which you are being prompted at the
            top of the screen. Some commands may have several locations that
            have to be selected. For each location, you will receive a
            prompt at the top of the screen. Simply move the mouse pointer
            to the desired location, and press the LEFT button.

   RIGHT  - Cancels the operation. In most cases this will return you directly
            to the top command level (no command active). In some cases, this
            will cancel a sub-function, and permit you to continue with the
            command.

Main COMMANDS:
-------------

The following commands are available from within MICROCAD at the top
command level.

A)rc

Prompts you for a "center" point, a starting point, and an ending point.
Draws an arc clockwise from the starting point to the ending point, which
would be a portion of a circle centered about the center point.

B)ox

This command prompts you to select two corners, and after the second
one is selected, MICROCAD will draw a BOX with diagonal corners on those
points.

C)ircle

Prompts you to select a center point, and then a second point. MICROCAD
will draw a circle about the center point, which includes the second point
in its circumference.

D)up

Prompts you to select an object, and then for a new insertion point. The
object is copied to the new point. Most useful for duplicating a "group"
that you have included from another file, or insuring that you get a circle
of exactly the same size etc. Duplicating an object takes only 7 bytes in
the drawing file, no matter how large or complicated the object is.

See the E)rase command below for details on selecting an object.

E)rase

Prompts you to select an object. To select an object, you must position
the cursor over the BASE POINT of that object. In general, the base point
will be the first point that you selected when defining the object.

To make it easier for you, MICROCAD constantly watches the cursor
position when this command is executed, and selects any object who's
base point comes in contact with the cursor. Once an object is selected,
MICROCAD indicates so, by temporarily removing it from the screen. Press
the LEFT button to accept this, and permanently erase the object.

If you accidently select an object that you don't want to erase, just
move the cursor away from it, and press the RIGHT button. MICROCAD will
restore it to the screen, and continue to search for other objects.

If more than one object has its base point at the same location, MICROCAD
will select the one which was defined first. You may accept this with the
LEFT button, or press the RIGHT button to switch to the next oldest one.
If you wish to cancel the selection in this case, you must keep pressing the
RIGHT button until all objects at that location have been skipped.

You may use the S)etup / B)ase-markers command to cause the base points
of all objects in the drawing to be made visible.

F)unc

This command brings up menu of misc. functions:

   F)ont

   Prompts you for a new character font file, and if given, loads it, and
   re-draws the drawing, using the new font.

   I)nsert

   Prompts you for a drawing filename, and then an insertion point. Inserts
   the contents of that drawing into the current drawing as a single object.
   The base point of the new object is the upper left corner of an invisible
   box, just large enough to include all object base points in the included
   drawing. This point will be shown by the cursor while selecting the new
   object location.

   If you wish to insert the same drawing several times, it takes much less
   space in the drawing file if you insert it once, and then use the duplicate
   function to create the other instances.

   L)oad

   Prompts for a filename, and loads a drawing from that file. Any unsaved
   changes to the current drawing are lost.

   Q)uit

   Terminates MICROCAD.

   S)ave

   Prompts for a filename, and saves the current drawing to that file.

L)ine

Prompts for a starting point, and then a series of end points. Each
time you select a new point, a line is drawn to it from the previous point.
Press the RIGHT button to stop drawing lines.

M)ove

Prompts you to select an object, and then for its new base point.
The object is then repositioned in the drawing.

See the 'E)rase' command for details on selecting an object.

R)edraw

Redisplays the drawing. This is useful to see any objects which are
overwritten by the text line at the top of the screen, and to "fix"
any breaks in lines, or missing grid markers causes by erasing of
overlaid objects.

S)etup

Brings up a menu of setup subcommands:

   B)ase-markers

   This command toggles ON/OFF the display of base points. See E)rase command
   for a description of base points. When ON, the base point for each object
   in the drawing will appear surrounded by a tiny box.

   C)urser-base

   Prompts you to select a base point for the cursor. After you select one,
   the cursor position shown in the upper right corner of the screen, will
   be relative to this position.

   G)rid

   Prompts for the spacing (in pixels) of the grid markers. Entering a
   blank line, or a value of zero turns off grid markers. Grid markers
   are simply "dots" placed at regular intervals, which you can use
   as a reference for aligning objects etc.

   S)nap

   Prompt for the spacing of "snap stops". When snap is enabled, the
   cursor is forced to "snap" into a grid of evenly placed stops. This
   makes it MUCH easier to align objects that you create. The "snap" grid
   should normally be set to some even fraction of the "G)rid" markers,
   although this is not enforced. Entering a blank line, or a value of
   zero turns off "snap", allowing the cursor to roam free.

   T)ext-scale

   This defines the size of text characters. Only affects text created
   after this command is used, allowing you to have several different
   sizes of text in the same drawing.

   The character set fonts used by MICROCAD are built on a matrix which
   is 16 pixels wide, by 24 pixels high. A scale value of 100 indicates
   that this original size will be used. A value of 50 would result in
   characters half as high and wide, while 200 would double the height
   and width.

NOTE: All of the above settings are saved in the drawing file, and will
therefore be restored when you subsequently edit the drawing.

T)ext

Inserts a text string into the drawing. You will be prompted for the
string to be inserted, and then for the position in the drawing.

U)ndo

Erases the last object which was created. Undo may be repeated, and each
time the youngest living object is removed. NOTE that U)ndo cannot reverse
operations like M)ove or E)rase.

MCPRINT Utility:
---------------

MICROCAD includes MCPRINT, which will print your drawing on an HP LaserJet
series or EPSON dot-matrix printer. MCPRINT works by building a raster bitmap
from your drawing, and then sending it to the printer. It should be fairly
easy to modify MCPRINT to work with other printers.

The syntax of the MCPRINT command is:

   MCPRINT <drawing file> <printer type> [F=font file] [D=device]

   <drawing file> is the name of a file containing the drawing that you
wish to print. The extension '.DWG' is assumed.

   <printer type> indicates which kind of printer you have. It should be
either LASERJET or EPSON.

   [font file] is the name of a file containing a character set font that
will be used to display any text in the drawing file. If you do not specify
a font file, The default MICROCAD.FNT is assumed.

   [device] is the DOS device to which the printer output will be written.
If you do not specify one, "LPT1" is assumed. You may also use this option
to direct the output to a file.

Misc. Notes:
-----------

MICROCAD does all of its internal calculations using 16 bit arithmetic.
Bacause of this, circles or arcs having a very large radius may not display
correctly. This is because these objects require manipulation of squares of
values, which may overflow 16 bits.

The GRID markers are not recorded as part of the object, and will "disappear"
if you M)ove, E)rase or U)ndo something that was on top of them. They will be
restored any time the screen is redrawn.

Character Fonts:
---------------

The following characters font files are included with MICROCAD:

   MICROCAD.FNT - This is the default MICROCAD font. It is a reasonable
                  quality font, which scales fairly well.
   HIGHRES.FNT  - This is a higher quality font, however it does not
                  scale to small sizes quite as well as MICROCAD.FNT.
   MATRIX.FNT   - A low (8x8) resolution font which looks like the
                  output from a dot matrix printer.
   THINLINE.FNT - A thin spidery font.

MICROCAD also includes a "font editor" (FE.COM) which allows you to create
and edit your own font files. The program is fairly self explainatory, just
run it and specify the name of the font file as an argument.

Drawing File Format:
-------------------

All entries in the drawing files produced by MICROCAD consist of 8 bit bytes
and 16 bit words. Word values are stored with the most significant byte first.

The first few bytes of the drawing file contain the "S)etup" values:

   Word = Grid spacing (0 = disable)
   Word = Snap spacing (0 = disable)
   Word = Text scale (100 = 1:1)
   Word = Cursor base X position
   Word = Cursor base Y position
   Byte = Basepoint display: 0 = ON, 1=OFF

Following the settings, the file will contain zero or more "objects",
representing lines, circles etc. The form of each type of object is:

END:    Byte = 0x00
        This is not required by MICROCAD, and is not normally produced by
        the program, however, an object consisting of a single 0x00 byte
        causes MICROCAD to stop drawing. This has two effects:
         1- If you are going to transmit the file using a protocol such as
            XMODEM which adds garbage to the end of the file, you could first
            append an END object to avoid "Corrupt drawing file".
         2- Once the END object is encountered, further additions to the
            drawing although recorded, are not displayed when the file is
            redrawn or reloaded.

LINE:   Byte = 0x01
        Word = Absolute X position of first point
        Word = Absolute Y position of first point
        Word = Relative X position of second point
        Word = Relative Y position of second point

BOX:    Byte = 0x02
        Word = Absolute X position of first point
        Word = Absolute Y position of first point
        Word = Relative X position of second point
        Word = Relative Y position of second point

CIRCLE: Byte = 0x03
        Word = Absolute X position of center point
        Word = Absolute Y position of center point
        Word = Radius of circle

TEXT:   Byte = 0x04
        Word = Absolute X position of text
        Word = Absolute Y position of text
        Word = Scale of text (100 = 1:1 = 16x24)
        Bytes= Text string
        Byte = 0 (zero termination)

ARC:    Byte = 0x05
        Word = Absolute X position of center point
        Word = Absolute Y position of center point
        Word = Radius of arc
        Word = Angle (0-255) to starting point.
        Word = Angle (0-255) to ending point.
        Angle:  0
                |
          192 --+-- 64
                |
               128

GROUP:  Byte = 0x06
        Word = Abolute X position of group
        Word = Abolute Y position of group
        Word = Size of following objects (in bytes)
        ...    Zero of more objects follow...
               X/Y positions are relative to group start.

ACOPY:  Byte = 0x07
        Word = Absolute X position of copy
        Word = Absolute Y position of copy
        Word = Byte offset of copied object from first object in file

RCOPY:  Byte = 0x08
        Word = Absolute X position of copy
        Word = Absolute Y position of copy
        Word = Byte offset of copied object from beginning of this object

The absolute copy is used whenever an object is duplicated via the D)up
function in MICROCAD. This form is more easy to manipulate when dealing
with discrete objects.

When objects are "grouped" (a drawing is inserted), any ACOPY objects are
changed to the relative RCOPY, so that we do not have to worry about them
shifting due to E)rase etc. This makes it much easier to treat the entire
group as a single object. This is safe to do, since the ACOPY must reference
an object in the same group, and the contents of a group are never altered.

This drawing file format is hearby placed in the public domain.

Finally:
-------

If anyone significantly enhances MICROCAD, or does something else truly
useful with it, I'd like to see the results.

      Dave Dunfield
      Dunfield Development Systems
      P.O. Box 31044
      Nepean, Ontario Canada
      K2B 8S8
      TEL: [phone]      BBS: Dial '2' at voice prompt
      FAX: [phone]       eg: atdt16132565820,,,,,,,2222

MICROCAD and its related utilities are compiled using the PC version of
my MICRO-C compiler. For more information on MICRO-C and my other products,
see the CATALOG file in this archive.