A.C.E. 3/ACE CD 3.iso/files/docs/ppaint6d.lha/PersonalPaint6.4Ch08.doc

Text File | 1996-03-16 | 29KB | 632 lines

               "Personal Paint  -  8. The Settings Menu"

 8. The Settings Menu
  8.1 Load Settings
  8.2 Save Settings
  8.3 Encryption Key
  8.4 Audio
  8.5 Coordinates
  8.6 Color Reduction
       8.6.1 Qualitative
       8.6.2 Quantitative
  8.7 Color Remapping
       8.7.1 Simple
       8.7.2 Pattern Dithering
       8.7.3 Floyd-Steinberg
 8.8 File Requester
       8.8.1Expand Path
       8.8.2 Directories on Top
       8.8.3 Sort by Date
       8.8.4 Double-Click
       8.8.5 Confirm Overwriting
  8.9 Icons
       8.9.1 No
       8.9.2 Yes (Default)
       8.9.3 Yes (Picture)
  8.10 Language
  8.11 Tool Bar
  8.12 Title Bar
  8.13 Clip Graphics
  8.14 Backfill Transparency
  8.15 Color Average Resize
  8.16 Workbench

8.         The Settings Menu

   All the functions described in this chapter deal with program and
environment settings (parameters). The former are common to the entire
program, while the latter may be different for each of the two images
(section 4.8).


8.1        Load Settings

   Most settings of Personal Paint can be saved to a file. This includes
settings defined in other program menus or requesters (printer options,
screen and image size, etc.)

   The standard file requester, described in section 3.4, is used to
select the file to be loaded. By default, the drawer where the program
loads and saves parameter files is "PPaint_Prefs", in the "PPaint"
volume.

   As described in sections 1.14 and 4.8, Personal Paint has two
environments. Each of the two has a full set of settings (mostly
image-oriented) completely independent from the other environment. The
program settings, however, are shared by the two environments. When a
parameter file is loaded, it affects the program settings used by both
environments, but only the environment settings of the current
environment. If a single file contains some environment settings which are
to be applied to both environments, that file must be loaded two times
(once from each environment). The "Startup_1.set", "Startup_2.set" and
"Startup_A.set" files in the "PPaint:PPaint_Prefs" drawer contain initial
settings for the two environments. Personal Paint automatically tries to
load these parameter files when the program is started. "Startup_A.set" is
generally defined by the disk configuration procedure (section 1.12), and
contains a few program settings.

   A parameter file may contain user interface settings, page and printer
setup for a particular printer, screen mode information, or just a
reference to a useful color palette (if one is found in a "Startup" file,
that palette becomes the default palette).

   Personal Paint does not put a minimum or maximum limit to the number of
parameters which can be set in a file. If the file being loaded contains
only a few assignments, only the settings referenced in the file will be
modified. No other program or environment settings are changed.

   It is often useful to extract and use only a few settings from a longer
parameter file. If, for example, a file contains definitions for image
colors, audio volume, page layout and image processing functions, but only
the latter are to be loaded, the parameters must be "filtered". After the
file has been selected with the file requester and loaded, a second
requester allows the user to select or discard some or all settings.

   The requester contains a standard scrolling list, which displays all
lines of the loaded file. A checkmark before each line indicates whether
that line (and the parameters it contains) should be accepted or not.
Wherever there is a checkmark, the corresponding program settings will be
changed. Clicking on a line cyclically sets or removes the checkmark. The
Include All and Exclude All gadgets can be used to quickly select or
discard all parameters.

   Only the parameters associated with the checkmarked lines are read. All
other parameters in the file are skipped. This makes it possible to
selectively load only part of the parameters in a file, without affecting
other settings.

   The file may include empty lines, or lines beginning with a comment
introducer (semicolon, ';'). Checkmarked or not, these lines are always
skipped by the program.

   If an error is found in the selected parameter file, or if the new
settings cannot be applied (e.g. no Chip RAM for a selected screen
format), all parameters are ignored and an error message is displayed.
Syntax errors are unlikely if the parameter file was written by Personal
Paint, but are possible if the file was typed or edited by hand. Appendix
A explains the possible error messages.


8.2        Save Settings

   This function is the opposite of "Load Settings". The current
environment settings and the program settings can be saved to a file to be
loaded again when necessary.

   A requester which allows the user to select which parameters are to be
saved is displayed. By default, all program and environment settings are
included in the file. As explained in section 8.1, the checkmarks to the
left of each line of parameters may be set or removed by clicking on the
line. Only the lines which have a checkmark are included in the file.

   As a rule, all parameters which are out of the scope of that particular
settings file should be excluded. A file intended to contain some
interesting image processing functions, for example, should not contain
printer or audio feedback settings. This simplifies future applications of
the files.

   When preparing one of the "Startup" files, it is sufficient to put
program settings in only one of the files (generally in "Startup_1"). When
Personal Paint is loaded, the startup settings files (if any exist) are
read in the following order: "Startup_A", "Startup_2" and "Startup_1". In
case of duplicate definitions of the same setting, the last definition
which is read is the one that counts.

   The standard file requester (section 3.4) is used to specify where the
file is to be saved, and with what name. As described in section 8.8.6, a
warning message can be displayed if a file with the same name would be
overwritten by the new file.

   A settings file is a plain ASCII text file. When Personal Paint stores
such a file, it uses only a minimum of comments, spaces and empty lines to
make the file more readable (for the user). If a word processor or text
editor is used to write a parameter file, and the same file is then loaded
and saved again by Personal Paint, comments, additional spaces and new
lines are stripped. Lower case letters in variable names are converted to
capital letters.

   If a settings file is created or edited manually, some syntax rules
should be followed. The file must begin with a "PPAINT SETTINGS" line.
Optional comments may begin with a semicolon (';') and end at the end of
the line. Combinations of both Horizontal Tab and Space characters (ASCII
decimal codes 9 and 32) are allowed as separators. Existing settings files
and appendix C are a useful reference.


8.3        Encryption Key

   The use of the encryption key in the context of loading and saving
files is described in sections 4.1 and 4.2.

   This requester is used to set or modify the encryption key. The last
key which was written remains stored (but unreadable) until a new key is
written, or Personal Paint is terminated. The encryption key is cleared
whenever the requester used to write a new key is displayed. The requester
can be used both for writing a key, or for quickly clearing the last used
key.

   Only two characters at a time are displayed in the string gadget of the
requester. This prevents the "casual" observer from reading the entire key
from the computer screen. Capitals and lower case letters are treated
differently (i.e. "Key" is not the same as "key"). The maximum length of
the key is 49 characters.

   If the Proceed gadget is selected immediately after the requester is
displayed, no encryption key will be present in the computer's memory. No
Cancel gadget exists, so it is impossible to re-use the previously written
key, unless it is written again.

   After the key has been written once, Personal Paint displays a second
requester to write the same code again. In this way a mistyped key cannot
be used by mistake to save an image, which then could not be loaded again
using the correct key. An error message is displayed if the control key is
different from the first key.

   It is important to note that the encryption key is not a simple access
code, but is used to greatly modify the image data. It will be impossible
to read the data with any program, unless the correct key is used. The
proprietary Cloanto two-phase encryption algorithm (encryption is applied
to compressed data) is a guarantee for data security.

   It is theoretically possible for an unauthorized person to load an
encrypted file by "guessing" the right key, or trying all most likely keys
until the right one is found. It is also likely that powerful computers
will be used to try all possible keys (character combinations). This can
take hundreds of years, but also much less. Some care should be taken in
advance to avoid such a risk. The key must never be written down. The key
should be long (at least 8 characters). Letters, numbers and other
characters should be mixed in the key. Names and dates are often too
obvious for an encryption key.

   Cloanto's Personal Write word processor, through its encryption
functions, has won a reputation and is widely used for preserving private
information and important secrets. Newer Amigas with almost
photographic-quality 256-color video modes, combined with lower-cost color
scanners and Personal Paint's encryption facility can provide similar
protection to images. Confidential Polaroid photographs, documents and
other material may be destroyed or stored to a most secure place after the
digital copy has been encrypted.


8.4        Audio

   The audio of Personal Paint consists of the sounds which are emitted
when different functions are selected. The audio is stereophonic. This
means that all sound signals are emitted in different ways on two audio
channels.

   Two sliders can be used separately to set the volume of error and cue
sounds. The cue signals are sounds emitted when a key is hit, or a gadget
or menu item is selected. All other sounds are error (or warning)
signals.

   A number to the left of each knob indicates the volume level. This can
range from 0 to 64. By default, the volume of error sounds is higher than
that used for other sounds.

   As explained in sections 1.11 ("Loading Personal Paint") and 1.13
("Installing Personal Paint"), the audio only works if the program can
activate the CloantoAudio unit. If the Audio Feedback option is disabled,
and no other program is using the audio module, CloantoAudio does not
occupy any RAM.


8.5        Coordinates

   These options activate the display of mouse pointer coordinates on the
title bar. The point of origin is always the top-left of the screen, and
may be equal to 0:0, or 1:1, depending on which subitem is selected. In
the first case coordinates start from zero, otherwise counting starts from
one.

   A double arrow precedes absolute coordinates (i.e. "normal" ones, from
the top left of the screen), while relative coordinates are introduced by
a single-headed arrow, which also indicates the direction of the pointer
from the origin (e.g. during the definition of a brush).

   Each environment may have its own coordinate settings.


8.6        Color Reduction

   Color reduction is the process of transforming an image into a second
image having a palette with fewer colors. This involves deciding how to
best represent the colored areas of the original image. Through dithering
and error diffusion (section 8.7) color remapping, it may be possible to
use Personal Paint's default palette to emulate the original colors.
However, considerably better results can be achieved by using a selection
of the original color palette. The following subsections explain different
options which are available.

   After the new colors have been chosen, the appearance of the
color-reduced image may be further improved by an appropriate color
remapping method (section 8.7). Section 10.4 discusses some compatibility
issues regarding palettes, color reduction and color remapping based on
Advanced Graphics Architecture Amiga systems.


8.6.1      Qualitative

   When deciding which colors of the original palette should be used in
the new image, the qualitative color reduction method gives more priority
to the colors for which there are not so many similar colors (and which
would therefore be represented not so well using the other colors). It
tries to preserve color variety and diversity, while limiting the loss of
hue-information.

   This type of color reduction may produce several new colors which did
not exist in the original palette, but which are the result of accurately
"merging" more source colors into one destination color.

   This works particularly well on pictures having lots of colors, like
some digitized photographs and computer graphics.


8.6.2      Quantitative

   The quantitative (or popular) color selection method gives priority to
the colors which are most used. It does so by creating a new palette which
contains only the most used colors of the original image. The new colors
are a subset of the original colors.

   This works very well on pictures whose colors have a similar hue
(section 7.1.3.2), like gray-shaded images and images based on two-color
spreads (e.g. many banknotes).


8.7        Color Remapping

   Color remapping is the process which has to be applied when rendering a
colored area in a different environment (where the original color may not
be available). The simplest method would be to pick the "closest" color in
the new environment. Other techniques combine existing colors in different
ways to simulate the original colors.

   Color remapping may automatically be applied by the program after color
reduction when an image is loaded or color-reduced. The palette which is
generated by the color reduction algorithm is not influenced by the
selected color remapping technique. This means that the same image,
remapped in different ways, will always have the same color palette. This
may be useful when different images with the same source palette (but
possibly remapped in different ways) have to be pasted together on the
same page.


8.7.1      Simple

   This is the most immediate (and fastest) color remapping method. Where
no color exists in the new environment, the closest existing color is
used. Existing pixels are simply remapped to a new color (if necessary).
The arrangement of pixels is not changed, even if some pixels may be
"lost" (as would be the case if two adjacent pixels originally having
different colors were remapped to the same color).

   This method is excellent, for example, for quickly loading and viewing
256-color images on systems which cannot display so many colors. From a
qualitative point of view, simple color remapping could be adequate for
remapping already "artificial" colors (e.g. in charts, histograms, etc.).


8.7.2      Pattern Dithering

   Pattern Dithering refers to the process of representing certain colors
(e.g. orange) with a constant pattern of other colors (e.g. red and
yellow). Section 4.3.2.1 has an interesting introduction to dithering
applied to printing.

   This process is quite suitable for remapping images containing larger
areas of the same color and simple transitions of gray or color. The human
eye is very good at recognizing regular patterns of dots, so the image
will look better from some distance.


8.7.3      Floyd-Steinberg

   Floyd-Steinberg is a more sophisticated, higher quality method of
dithering. It employs special error diffusion techniques to distribute
pixels of different colors without creating noticeable patterns.

   Floyd-Steinberg can generally represent more colors and softer shades
than the other color remapping methods. It may also be considerably slower
than other techniques.

   To give an example of the capabilities of this method, it is
interesting to note how a 256-color image (320 by 200 pixels) may look
better in high resolution (640 by 400) with only 16 colors using
Floyd-Steinberg, than it would look in 64 colors (320 by 200 format) with
a different color remapping.


8.8        File Requester

   This group of settings allows the user to control some aspects of the
file requester (section 3.4). Each parameter is associated with a menu
subitem which can be selected and deselected with the mouse (section
1.9.8, "Menus"). The following subsections explain each parameter in
detail.


8.8.1      Expand Path

   This parameter determines whether the program can modify the content of
the "Path" string gadget of the file requester.

   If the option is enabled (as it is by default), Personal Paint
transforms device names (e.g. "DF0") into volume names (e.g. "PPaint_2").
This facilitates the access of files stored on disks (or other media)
which are moved from one drive to another. Also, logical names (like
"PPaint") are expanded to the full paths (e.g. "Work:Graphics/PPaint")
originally assigned to them. This makes it easier for the user to
understand the position of each file. The file requester's directory lists
can be stored more efficiently if this option is enabled (multiple
occurrences of the same list are always recognized).

   If the option is disabled, the program never modifies the names which
are written in the "Path" string gadget. This may be useful if logical
names are used on purpose, for example if the "PPaint" logical name is
used to access files in an installation-independent manner. This is
necessary if the path name has to be stored in a settings file which could
be loaded on a different computer. A full path, like
"Work:Graphics/PPaint", may be valid on one system, but could lead to
unexpected results on different computer configurations (where Personal
Paint may be stored in different drawers). In such cases, logical names
must be used. Sections 1.12 ("Environment Variables and Standard Drawers")
and 9.1 ("AskAssign") explain how to work with logical names.


8.8.2      Directories on Top

   This option determines whether directory names should be placed at the
top or at the bottom of the file requester scrolling lists. By default,
file names appear at the top, and directory names at the bottom.


8.8.3      Sort by Date

   Files may be sorted by name (lexicographic order), or by the
last-modification date. The system date and time must always be up-to-date
for the latter option to work properly.


8.8.4      Double-Click

   When this option is selected, the names displayed in the list box of
the file requester can be selected by double-clicking the left mouse
button. The requester disappears as if the "Proceed" gadget had been
selected. The speed at which the button must be pressed can be set through
the Amiga Preferences, as described in the Amiga documentation.

   If the option is disabled, the names can still be selected with the
mouse, but double-clicks are not interpreted in any special way.


8.8.5      Confirm Overwriting

   This parameter affects only the requesters used to define a name for a
file to be written by Personal Paint. If this parameter is set, a second
requester is displayed if the file already exists and would be overwritten
by the operation being executed.

   The warning requester contains two gadgets: Proceed and Cancel. If
"Cancel" is selected, the function is aborted, and no file is written.


8.9        Icons

   When a file is written by Personal Paint, a Workbench icon (section
1.9.7) can automatically be saved with it. An icon is a particular kind of
gadget, displayed by the Workbench program, which makes a file immediately
recognizable through a graphical image. Icons can be used to select, load,
rename, copy or delete the associated file (or drawer, or volume) using
the mouse.

   A small disadvantage of icons is that they contain graphical data,
which requires some - though not a lot of - memory. Personal Paint's
default image file icons occupy less than 488 bytes of memory. For the
more technically interested users, this means that an icon occupies only
one disk sector on any Amiga filing system (a sector in the original
non-FFS Amiga filing system can store 488 bytes of data), plus one sector
for the directory entry. More than 800 of these icons can fit on a
standard 880 kbyte disk.

   Personal Paint's icons store some additional data in the Default Tool
and Tool Types fields. This tells the operating system where to find the
program which created the file when its icon is double-clicked, and gives
additional information (file format, image size, etc.) which can be edited
by selecting the desired icon (one click of the mouse button) and choosing
the Information (or Info, on some systems) Workbench menu item. The
default information which is stored can be modified by editing the icons
in the "PPaint_Icons" drawers.


8.9.1      No

   If the disk space is to be highly optimized, or if icons are never
used, the No option can be selected to save files without an associated
icon.


8.9.2      Yes (Default)

   The Default option enables writing of Personal Paint's default icons.
Different icon images are used to distinguish between the files saved by
the program (pictures, brushes, settings, etc.) These icons are stored in
the "PPaint_Icons" drawer associated to the current Workbench colors (1.3
or 2.0 colors), where they can be modified with a tool like IconEdit
(which can be found on the Amiga Workbench disk).


8.9.3      Yes (Picture)

   The Picture option uses default icons except for picture and brush
files, where the current image or brush is used to create the icon image.
The image is resized, if this is necessary to make it fit into the
standard icon width and Workbench display ratio. The current Workbench
colors are used to apply a Floyd-Steinberg remapping.

   It should be kept in mind that users on different Amiga systems may
have different Workbench color settings and display ratios (e.g.
interlaced vs. non-interlaced), which may cause icons created on one
system to appear differently on another system.

   On newer versions of the Amiga operating system, it is possible to
specify the number of colors to be used for the Workbench screen. Personal
Paint's Picture icons can fully exploit, giving impressive results, up to
256 Workbench colors. There is a potential drawback, however. Only the
first four and the last four colors of the Workbench palette are
guaranteed by the system to remain constant. The other colors may be
changed for particular operating system tasks (like displaying images or
setting a new Workbench background pattern). Since this feature would not
be completely supported in all possible conditions, Personal Paint uses
more than eight Workbench colors only if the <Shift> key is held down
while the icon is saved (i.e. just after the end of the Save Image
progress indicator).


8.10       Language

   Most versions of Personal Paint come with user interface texts in
different languages. The Language menu item has one subitem for each
available language. With this option, it is possible to select the
language used to display all menus, gadgets and program texts.

   The default language is normally set in the "Startup_A" file by the
disk configuration procedure (section 1.12). Any custom settings in the
"Startup_1" or "Startup_2" files would override the default language.

   Section 1.14 has more on the user interface files which are loaded when
a Language menu item is selected. The current language can be reselected,
if the file has been changed since it was last used by Personal Paint. A
warning message is displayed if any texts exceed some simple
range-checking length limits.


8.11       Tool Bar

   As explained in section 3.1, the tool bar can be removed from the
screen to view a larger image area. All tools remain accessible through
the keyboard shortcuts (Appendix B). Selecting the option again puts the
tool bar back.


8.12       Title Bar

   The title bar can be removed and redisplayed in a way similar to the
tool bar. Menus are accessible by clicking on the right mouse button when
the pointer is moved over the topmost screen line.

   As explained in more detail in section 3.2, in some overscan video
modes the mouse pointer image may not completely reach the region which
would normally be covered by the title bar. Even if there apparently is no
system pointer feedback, Personal Paint continues to process mouse actions
correctly. Personal Paint's brush-shaped pointer remains visible at the
correct location.


8.13       Clip Graphics

   By default, all graphics operations may extend beyond the visible image
limits. For example, flood-filling an entirely blue page with white color
would allow the white to fill even those areas which are beyond the screen
borders.

   If this option is set, the effects of all paint and image processing
functions are limited to visible screen areas.


8.14       Backfill Transparency

   Sections 5.7.1 and 5.8.5 to 5.8.7 explain how to apply transparency to
brush operations. Normally, when a custom brush is defined, all
background-colored areas are marked as transparent for future operations.

   If the Backfill Transparency option is set, only those
background-colored areas which surround the brush are set to be
transparent. Parts of the brush which are surrounded by other colors do
not become transparent. This works a bit like "lassoing" the image.

   Changing the status of this option does not change the transparency of
brushes which were already defined. The transparency plane of the current
custom brush can be updated to the new mode by selecting the New
Transparency option (section 5.8.5). Other ways of setting transparent
areas are described in sections 5.8.6 and 5.8.7.

   Brushes which are loaded from a file always inherit their transparency
from the associated transparency information (IFF-ILBM format). If the
file does not contain any transparency data, the current transparency mode
is applied.


8.15       Color Average Resize

   All functions which reduce an image down to a smaller dimension are
likely to cause a loss of data. The most used functions in this category
include resizing of brushes and stretching of images to different
formats.

   Since the size of the dots which make up the image is device-dependent
and cannot be changed, the number of dots is reduced. Halving a brush, for
example (section 5.10.4), reduces the number of pixels to about one
quarter of the dots in the original brush. Even for a human, it is not
easy to decide which dots to "sacrifice".

   If this option is enabled, the pixels which are sacrificed are taken
into account when creating the destination pixels. A group of two yellow
and two red dots, for example, might be reduced to a single orange pixel.
On borders between highly contrasting colors, this results in an effect
also known as anti-aliasing.

   Best results can be achieved when several colors whose hue (section
7.1.3.2) is similar to that of the original image can be used in the
destination image. For example, a black and white image (or text) can be
reduced with excellent results if the destination color palette contains
many different shades of gray.

   Color average resizing is more complex than plain resizing, and
therefore increases demand for processing power or execution time.


8.16       Workbench

   Personal Paint allows the user to manually close and reopen the
Workbench screen (normally used by the Amiga operating system to display
disk icons, Shell and Console windows and any windows opened by other
programs).

   More than 40 kbytes of RAM are freed when a PAL-size Workbench screen
of 256 lines, 640 pixels wide, with four colors (two bit planes) is
closed. Personal Paint automatically tries to close the Workbench screen
if the computer has less than 1 Mbyte of Chip RAM.

   The Workbench screen is public, i.e. it may be used by other programs.
This may be a problem when the Workbench program tries to close its
screen, because it must be free of other windows before it can be closed.
Windows used to display the contents of storage devices and drawers are
closed directly by the Workbench. Other programs (including Amiga system
software) which have an open window on the Workbench screen must generally
be terminated before the screen can be closed.

   If the option is selected when the screen is closed, Personal Paint
attempts to reopen the Workbench screen. If there is enough Chip RAM, the
screen and its windows are reopened.