Pmw.Color

Description

This is a set of functions for manipulating colors and for modifying the color scheme of an application or a widget. Colors can be represented in a number of ways:

name

a standard color name, eg 'orange' or '#ffa500'

rgb

a 3-element sequence of red, green and blue intensities each between 0.0 (dark) and 1.0 (light), eg [1.0, 0.6, 0.0].

hsi

a 3-element sequence (hue, saturation, intensity). The value of hue is between 0.0 and 2pi (6.28318) giving a range of colors covering, in order, red, orange, yellow green, cyan, blue, magenta and back to red. The value of saturation is between 0.0 (grey) and 1.0 (brilliant) and the value of intensity is between 0.0 (dark) and 1.0 (bright).

brightness As used in these functions, the brightness of a color is the brightness as registered by the human eye. For example, even though the colors red, blue and yellow have the same intensity (1.0), they have different brightnesses, 0.299, 0.114 and 0.886 respectively, reflecting the different way these colors appear to the eye. The brightness of a color is a value between 0.0 (dark) and 1.0 (bright).

color scheme A color scheme is a set of colors defined for each of the default color options in the Tk option database. Color schemes can be used in two ways. Firstly, using Pmw.Color.setscheme(), the Tk option database can be set to the values in the color scheme. This will not have any effect on currently existing widgets, but any new widgets created after setting the options will have these colors as their defaults. Secondly, using Pmw.Color.changecolor() the color scheme can be used to change the colors of a widget and all its child widgets.

A color scheme is specified by defining one or more color options (one of the defined options must be background). Not all options need be specified - if any options are not defined, they are calculated from the other colors. These are the options used by a color scheme, together with their values if not specified:

 background:            (must be specified)
 foreground:            black
 activeForeground:      same as foreground
 insertBackground:      same as foreground
 selectForeground:      same as foreground
 highlightColor:        same as foreground
 disabledForeground:    between fg and bg but closer to bg
 highlightBackground:   same as background
 activeBackground:      a little lighter that bg
 selectBackground:      a little darker that bg
 troughColor:           a little darker that bg
 selectColor:           yellow

Functions

The following functions are available.

Pmw.Color.average(col1, col2, fraction)

Pmw.Color.bordercolors(root, color)

Pmw.Color.changebrightness(root, colorName, brightness)

Find the hue of the color colorName and return a color of this hue with the required brightness.

Pmw.Color.changecolor(widget, background = None, **kw)

Change the color of widget and all its child widgets according to the color scheme specified by the other arguments. This is done by modifying all of the color options of existing widgets that have the default value. The color options are the lower case versions of those described in the color scheme section. Any options which are different to the previous color scheme (or the defaults, if this is the first call) are not changed.

For example to change a widget to have a red color scheme with a white foreground:

 Pmw.Color.changecolor(widget,
     background = 'red3', foreground = 'white')

The colors of widgets created after this call will not be affected.

Note that widget must be a Tk widget or toplevel. To change the color of a Pmw megawidget, use it's hull component. For example:

 widget = megawidget.component('hull')
 Pmw.Color.changecolor(widget, background = 'red3')

Pmw.Color.correct(rgb, correction)

Pmw.Color.getdefaultpalette(root)

Return a dictionary of the default values of the color options described in the color scheme section.

To do this, a few widgets are created as children of root, their defaults are queried, and then the widgets are destroyed. (Tk supplies no other way to get widget default values.)

Note that root must be a Tk widget or toplevel. To use a Pmw megawidget as the root, use it's hull component. For example:

 root = megawidget.component('hull')
 Pmw.Color.getdefaultpalette(root)

Pmw.Color.hsi2rgb(hue, saturation, intensity)

Return a list of rgb values of the color corresponding to hue, saturation and intensity.

Pmw.Color.hsi2saturation(brightness, h, i)

Pmw.Color.hue2name(hue, brightness = None)

Return the color with the specified hue and brightness. If hue is None, return a grey of the requested brightness. Otherwise, the value of hue should be as described above.

Pmw.Color.rgb2brightness(rgb)

Pmw.Color.rgb2hsi(rgb)

Return a tuple (hue, saturation, intensity) corresponding to the color specified by the rgb sequence.

Pmw.Color.rgb2name(rgb)

Pmw.Color.setscheme(root, background = None, **kw)

Set the color scheme for the application by setting default colors (in the Tk option database of the root window of root) according to the color scheme specified by the other arguments.

For example to initialise an application to have a red color scheme with a white foreground:

 Pmw.Color.setscheme(root,
     background = 'red3', foreground = 'white')

This function does not modify the colors of already existing widgets. Use Pmw.Color.changecolor() to do this.

Note that root must be a Tk widget or toplevel. To use the Tk option database of the root window or a Pmw megawidget, use the megawidget's hull component. For example:

 root = megawidget.component('hull')
 Pmw.Color.setscheme(root, background = 'red3')

Pmw.Color.spectrum(numColors, correction = 1.0, saturation = 1.0, intensity = 1.0, extraOrange = 1, returnHues = 0)