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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