cpython/Tools/pynche/README

Pynche - The PYthonically Natural Color and Hue Editor
Copyright (C) 1998 CNRI
Author: Barry A. Warsaw <bwarsaw@python.org>

Pynche is a color editor based largely on a similar program that I
originally back in 1987 for the Sunview window system.  That editor
was called ICE, the Interactive Color Editor.  I'd always wanted to
port this program to X but didn't feel like hacking X and C code to do
it.  Fast forward many years, to where Python + Tkinter provides such
a nice programming environment, with enough power, that I finally
buckled down and implemented it.  I changed the name because these
days, too many other systems have the acronym `ICE'.

Pynche has been tested with Python 1.5.1 using Tk 8.0.  It probably
works with Python 1.5.  I've tested it on both Solaris 2.6 and Windows 
NT.  There are some funky things that happen on Windows but I think
they are primarily Tk problems.  You'll want to be sure to have Tk
8.0.3 for Windows.  Also, Pynche is very colormap intensive, so it
doesn't work very well on 8-bit graphics cards.  I'll probably fix
that in the future.

Pynche must find a text database of colors, in the X11 format.  Pynche
is distributed with an rgb.txt file from the X11R6.4 distribution for
this reason, but you can use a different file with the -d option.  The
file xlicense.txt contains the license only for rgb.txt.

Pynche is pronounced `Pinch-ee'.  Start it by running the pynche.py
driver.  On Windows, run pynche.pyw to inhibit the console window.

The top part of the main Pynche window contains the "variation
strips".  Each strip contains a number of "color chips".  The strips
always indicate the currently selected color by a highlight rectangle
around the selected color chip, with an arrow pointing to the chip.
Each arrow has an associated number giving you the color value along
the variation's axis.  Each variation strip shows you the colors that
are reachable from the selected color by varying just one axis of the
color solid.

For example, when the selected color is (in Red/Green/Blue notation)
127/127/127, the Red Variations strip shows you every color in the
range 0/127/127 to 255/127/127.  Similarly for the green and blue
axes.  You can select any color by clicking on its chip.  This will
update the highlight rectangle and the arrow, as well as other
displays in Pynche.

Click on "Update while dragging" if you want Pynche to update the
selected color while you drag along any variation strip (this will be
slower).  Click on "Hexadecimal" to display the arrow numbers in hex.

In the lower left corner of the main window you see two larger color
chips.  The Selected chip shows you a larger version of the color
selected in the variation strips, along with its X11 color
specification.  The Nearest chip shows you the closest color in the
X11 database to the selected color, giving its X11 color name.
Clicking on the Nearest color chip selects that color.  Color distance 
is calculated in the 3D space of the RGB color solid and if more than
one color name is the same distance from the selected color, the first 
one found will be chosen.

Note that there may be more than one X11 color name for the same RGB
value.  In that case, the first one found in the text database is
designated the "primary" name, and this is shown under the Nearest
chip.  The other names are "aliases" and they are visible in other
Pynche windows.

At the lower right of the main window are three entry fields.  Here
you can type numeric values for any of the three color axes.  Legal
values are between 0 and 255, and these fields do not allow you to
enter illegal values.  You must hit Enter or Tab to select the new
color.

Click on "Update while typing" if you want Pynche to select the color
on every keystroke (well, every one that produces a legal value!).
Click on "Hexadecimal" to display and enter color values in hex.

There are three secondary windows which are not displayed by default.
You can bring these up via the "View" menu on the main Pynche window.

The "Text Window" allows you to see what effects various colors have
on the standard Tk text widget elements.  In the upper part of the
window is a plain Tk text widget and here you can edit the text,
select a region of text, etc.  Below this is a button "Track color
changes".  When this is turned on, any colors selected in the other
windows will change the text widget element specified in the radio
buttons below.  When this is turned off, text widget elements are not
affected by color selection.

You can choose which element gets changed by color selection by
clicking on one of the radio buttons in the bottom part of this
window.  Text foreground and background affect the text in the upper
part of the window.  Selection foreground and background affect the
colors of the primary selection which is what you see when you click
the middle button (depending on window system) and drag it through
some text.

The Insertion is the insertion cursor in the text window, where new
text will be inserted as you type.  The insertion cursor only has a
background.

The "Color List" window shows every color in the text database.  This
is the primary reason why Pynche doesn't work so well on 8-bit
screens.  In the upper part of the window you see a scrolling list of
all the color names in the database, in alphabetical order.  Click on
any color to select it.  In the bottom part of the window is displayed 
any aliases for the selected color (those color names that have the
same RGB value, but were found later in the text database).  For
example, find the color "Black" and you'll see that its aliases are
"gray0" and "grey0".

If the color has no aliases you'll see "<no aliases>" here.  If you
just want to see if a color has an alias, and do not want to select a
color when you click on it, turn off "Update on Click".

Note that the color list is always updated when a color is selected
from the main window.  There's no way to turn this feature off.  If
the selected color has no matching color name you'll see
"<no matching color>" in the Aliases window.

The "Details" window gives you more control over color selection than
just clicking on a color chip in the main window.  The row of buttons
along the top apply the specified increment and decrement amounts to
the selected color.  These delta amounts are applied to the variation
strips specified by the check boxes labeled "Move Sliders".  Thus if
just Red and Green are selected, hitting -10 will subtract 10 from the 
color value along the red and green variation only.  Note the message
under the checkboxes; this indicates the primary color level being
changed when more than one slider is tied together.  For example, if
Red and Green are selected, you will be changing the Yellow level of
the selected color.

The "At Boundary" behavior determines what happens when any color
variation hits either the lower or upper boundaries (0 or 255) as a
result of clicking on the top row buttons:

    Stop
        When the increment or decrement would send any of the tied
        variations out of bounds, the entire delta is discarded.

    Wrap Around
        When the increment or decrement would send any of the tied
        variations out of bounds, the out of bounds value is wrapped
        around to the other side.  Thus if red were at 238 and +25
        were clicked, red would have the value 7.

    Preseve Distance
        When the increment or decrement would send any of the tied
        variations out of bounds, all tied variations are wrapped as
        one, so as to preserve the distance between them.  Thus if
        green and blue were tied, and green was at 238 while blue was
        at 223, and +25 were clicked, green would be at 15 and blue
        would be at 0.

    Squash
        When the increment or decrement would send any of the tied
        variations out of bounds, the out of bounds variation is set
        to the ceiling of 255 or floor of 0, as appropriate.  In this
        way, all tied variations are squashed to one edge or the
        other.

The top row buttons have the following keyboard accelerators:

    -25 == Shift Left Arrow
    -10 == Control Left Arrow
     -1 == Left Arrow
     +1 == Right Arrow
    +10 == Control Right Arrow
    +25 == Shift Right Arrow

Other keyboard accelerators:

    Alt-w in any secondary window dismisses the window.  In the main
    window it exits Pynche.

    Alt-q in any window exits Pynche.