Pynche - The PYthonically Natural Color and Hue Editor

Contact: Barry A. Warsaw
Email: bwarsaw@python.org
Version: 1.3

Introduction

 Pynche is a color editor based largely on a similar program that I
 originally wrote 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 re-implemented it. I
 changed the name because these days, too many other systems have
 the acronym `ICE'.

 Pynche should work with any variant of Python after 1.5.2
 (e.g. 2.0.1 and 2.1.1), using Tk 8.0.x. It's been tested on
 Solaris 2.6, Windows NT 4, and various Linux distros. You'll want
 to be sure to have at least Tk 8.0.3 for Windows. Also, Pynche is
 very colormap intensive, so it doesn't work very well on 8-bit
 graphics cards; 24bit+ graphics cards are so cheap these days,
 I'll probably never "fix" that.

 Pynche must find a text database of colors names in order to
 provide `nearest' color matching. Pynche is distributed with an
 rgb.txt file from the X11R6.4 distribution for this reason, along
 with other "Web related" database (see below). You can use a
 different file with the -d option. The file xlicense.txt contains
 the license only for rgb.txt and both files are in the X/
 subdirectory.

 Pynche is pronounced: Pin'-chee


Running Standalone

 On Unix, start it by running the `pynche' script. On Windows, run
 pynche.pyw to inhibit the console window. When run from the
 command line, the following options are recognized:

 --database file
 -d file
 Alternate location of the color database file. Without this
 option, the first valid file found will be used (see below).

 --initfile file
 -i file
 Alternate location of the persistent initialization file. See
 the section on Persistency below.

 --ignore
 -X
 Ignore the persistent initialization file when starting up.
 Pynche will still write the current option settings to the
 persistent init file when it quits.

 --help
 -h
 Print the help message.

 initialcolor
 a Tk color name or #rrggbb color spec to be used as the
 initially selected color. This overrides any color saved in
 the persistent init file. Since `#' needs to be escaped in
 many shells, it is optional in the spec (e.g. #45dd1f is the
 same as 45dd1f).


Running as a Modal Dialog

 Pynche can be run as a modal dialog, inside another application,
 say as a general color chooser. In fact, Grail 0.6 uses Pynche
 and a future version of IDLE may as well. Pynche supports the API
 implemented by the Tkinter standard tkColorChooser module, with a
 few changes as described below. By importing pyColorChooser from
 the Pynche package, you can run

 pyColorChooser.askcolor()

 which will popup Pynche as a modal dialog, and return the selected
 color.

 There are some UI differences when running as a modal
 vs. standalone. When running as a modal, there is no "Quit" menu
 item under the "File" menu. Instead there are "Okay" and "Cancel"
 buttons.

 When "Okay" is hit, askcolor() returns the tuple

 ((r, g, b), "name")

 where r, g, and b are red, green, and blue color values
 respectively (in the range 0 to 255). "name" will be a color name
 from the color database if there is an exact match, otherwise it
 will be an X11 color spec of the form "#rrggbb". Note that this
 is different than tkColorChooser, which doesn't know anything
 about color names.

 askcolor() supports the following optional keyword arguments:

 color
 the color to set as the initial selected color

 master[*]
 the master window to use as the parent of the modal
 dialog. Without this argument, pyColorChooser will create
 its own Tkinter.Tk instance as the master. This may not
 be what you want.

 databasefile
 similar to the --database option, the value must be a
 file name

 initfile[*]
 similar to the --initfile option, the value must be a
 file name

 ignore[*]
 similar to the --ignore flag, the value is a boolean

 wantspec
 When this is true, the "name" field in the return tuple
 will always be a color spec of the form "#rrggbb". It
 will not return a color name even if there is a match;
 this is so pyColorChooser can exactly match the API of
 tkColorChooser.

 [*] these arguments must be specified the first time
 askcolor() is used and cannot be changed on subsequent calls.


The Colorstrip 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 a bit slower). Click on "Hexadecimal" to display the arrow
 numbers in hex.

 There are also two shortcut buttons in this window, which
 auto-select Black (0/0/0) and White (255/255/255).


The Proof Window

 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
 specification, and below that, its X11 color name. When the
 Selected chip color exactly matches the Nearest chip color, you
 will see the color name appear below the color specification for
 the Selected chip.

 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 the Color List Window (see below).

 Both the color specifications and color names are selectable for
 copying and pasting into another window.


The Type-in Window

 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.


Other Views

 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

 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

 The "Color List" window shows every named color in the color name
 database (this window may take a while to come up). 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

 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.

 Preserve 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


Keyboard Accelerators

 Alt-w in any secondary window dismisses the window. In the main
 window it exits Pynche (except when running as a modal).

 Alt-q in any window exits Pynche (except when running as a modal).


Persistency

 Pynche remembers various settings of options and colors between
 invocations, storing these values in a `persistent initialization
 file'. The actual location of this file is specified by the
 --initfile option (see above), and defaults to ~/.pynche.

 When Pynche exits, it saves these values in the init file, and
 re-reads them when it starts up. There is no locking on this
 file, so if you run multiple instances of Pynche at a time, you
 may clobber the init file.

 The actual options stored include

 - the currently selected color

 - all settings of checkbox and radio button options in all windows

 - the contents of the text window, the current text selection and
 insertion point, and all current text widget element color
 settings.

 - the name of the color database file (but not its contents)

 You can inhibit Pynche from reading the init file by supplying the
 --ignore option on the command line. However, you cannot suppress
 the storing of the settings in the init file on Pynche exit. If
 you really want to do this, use /dev/null as the init file, using
 --initfile.


Color Name Database Files

 Pynche uses a color name database file to calculate the nearest
 color to the selected color, and to display in the Color List
 view. Several files are distributed with Pynche, described
 below. By default, the X11 color name database file is selected.
 Other files:

 html40colors.txt -- the HTML 4.0 guaranteed color names

 websafe.txt -- the 216 "Web-safe" colors that Netscape and MSIE
 guarantee will not be dithered. These are specified in #rrggbb
 format for both values and names

 webcolors.txt -- The 140 color names that Tim Peters and his
 sister say NS and MSIE both understand (with some controversy over
 AliceBlue).

 namedcolors.txt -- an alternative set of Netscape colors.

 You can switch between files by choosing "Load palette..." from
 the "File" menu. This brings up a standard Tk file dialog.
 Choose the file you want and then click "Ok". If Pynche
 understands the format in this file, it will load the database and
 update the appropriate windows. If not, it will bring up an error
 dialog.


To Do

 Here's a brief list of things I want to do (some mythical day):

 - Better support for resizing the top level windows

 - More output views, e.g. color solids

 - Have the notion of a `last color selected'; this may require a
 new output view

 - Support setting the font in the text view

 - Support distutils setup.py for installation

 I'm open to suggestions!



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