Learning Perl/Tk

16.2. Color-Related Methods

There are four methods that deal with color: colormapfull, rgb, cells, and depth.

16.2.1. Is the Colormap Full?

To determine if the colormap for the widget is full, use colormapfull:

$isfull = $widget->colormapfull();

Thecolormapfull method returns a 1 if the colormap is full and if it is not full.

16.2.2. Cell Count

The number of cells in the colormap can be obtained by using the cells method:

$count = $widget->cells();

The value returned is a number indicating the number of colors; for example, 64.

16.2.3. Color Depth

You can get the number of bits per pixel by using the depth method:

$depth = $widget->depth();
# $depth might contain "16"

16.2.4. Translate to RGB Value

You can translate a color name to the red, green, and blue values by using the rgb method. Send rgb a color name (valid color names were covered in Chapter 3) and it returns a list containing three items that represent the red, green, and blue numbers.

($red, $green, $blue) = $widget->rgb("color");

Now $red, $green,and $blue each contain an integer from to 255.

16.2.5. Setting Colors

You can have your entire application based on one color automatically by using the setPalette method:

$widget->setPalette(color);

The background color of $widget is set to the specified color, and the colors for all other widgets are calculated based on that color. So if a button's edge is a lighter color than the background, it will show up a lighter shade of whatever color you picked. This method ...