<html> <head> <meta name="description" content="Pmw - a toolkit for building high-level compound widgets in Python"> <meta name="content" content="python, megawidget, mega widget, compound widget, gui, tkinter"> <title>Pmw.Color reference manual</title> </head> <body bgcolor="#ffffff" text="#000000" link="#0000ee" vlink="551a8b" alink="ff0000"> <h1 ALIGN="CENTER">Pmw.Color</h1> <dl> <dt> <h3>Name</h3></dt><dd> <p>Pmw.Color - contains functions for handling colors and color schemes</p> <p></p> </dd> <dt> <h3>Description</h3></dt><dd> <p> This module is a set of functions for manipulating colors and for modifying the color scheme of an application or a widget. Many of the functions in this module take or return colors. These values may represent colors in the following ways:</p> <dl><dt><strong>name</strong></dt><dd>a standard color name, eg <code>'orange'</code> or <code>'#ffa500'</code><p></p> </dd> <dt><strong>rgb</strong></dt><dd>a 3-element sequence of red, green and blue intensities each between 0.0 (dark) and 1.0 (light), eg <code>[1.0, 0.6, 0.0]</code>.<p></p> </dd> <dt><strong>hsi</strong></dt><dd>a 3-element sequence (<em>hue</em>, <em>saturation</em>, <em>intensity</em>). The value of <em>hue</em> is between 0.0 and <strong>2pi</strong> (6.28318) giving a range of colors covering, in order, red, orange, yellow green, cyan, blue, magenta and back to red. The value of <em>saturation</em> is between 0.0 (grey) and 1.0 (brilliant) and the value of <em>intensity</em> is between 0.0 (dark) and 1.0 (bright).<p></p> </dd></dl> <p> As used in these functions, the <strong>brightness</strong> of a color is the perceived grey level of the color 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).</p> <p> A <strong>color scheme</strong> 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 <code>Pmw.Color.setscheme()</code>, 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 <code>Pmw.Color.changecolor()</code> the color scheme can be used to change the colors of a widget and all its child widgets.</p> <p> A color scheme is specified by defining one or more color options (one of the defined options must be <code>background</code>). 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:</p> <dl><dd><pre> 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</pre></dd></dl> <p> There are many functions in this module. As well as <code>Pmw.Color.setscheme()</code> and <code>Pmw.Color.changecolor()</code>, some of the most useful are <code>Pmw.Color.spectrum()</code>, <code>Pmw.Color.changebrightness()</code> and <code>Pmw.Color.getdefaultpalette()</code>.</p> <p></p> </dd> <dt> <h3>Functions</h3></dt><dd> The following functions are available.<p></p> <dl> <dt> <strong>Pmw.Color.average</strong>(<em>rgb1</em>, <em>rgb2</em>, <em>fraction</em>)</dt><dd> Return an <strong>rgb</strong> color <em>fraction</em> of the way "between" the colors <em>rgb1</em> and <em>rgb2</em>, where <em>fraction</em> must be between <strong>0.0</strong> and <strong>1.0</strong>. If <em>fraction</em> is close to <strong>0.0</strong>, then the color returned will be close to <em>rgb1</em>. If it is close to <strong>1.0</strong>, then the color returned will be close to <em>rgb2</em>. If it is near <strong>0.5</strong>, then the color returned will be half way between the two colors.</p> <p></p> </dd> <dt> <strong>Pmw.Color.bhi2saturation</strong>(<em>brightness</em>, <em>hue</em>, <em>intensity</em>)</dt><dd> Return the saturation of the color represented by <em>brightness</em>, <em>hue</em> and <em>intensity</em>.</p> <p></p> </dd> <dt> <strong>Pmw.Color.bordercolors</strong>(<em>root</em>, <em>colorName</em>)</dt><dd> Return a tuple <code>(light, dark)</code> of color names that can be used as the light and dark border shadows on a widget where the background is <em>colorName</em>. This is the same method that Tk uses for shadows when drawing reliefs on widget borders. The <em>root</em> argument is only used to query Tk for the <strong>rgb</strong> values of <em>colorName</em>.</p> <p></p> </dd> <dt> <strong>Pmw.Color.changebrightness</strong>(<em>root</em>, <em>colorName</em>, <em>brightness</em>)</dt><dd> Find the hue of the color <em>colorName</em> and return a color of this hue with the required <em>brightness</em>. If <em>brightness</em> is <strong>None</strong>, return the name of color with the given hue and with saturation and intensity both <strong>1.0</strong>. The <em>root</em> argument is only used to query Tk for the <strong>rgb</strong> values of <em>colorName</em>.</p> <p></p> </dd> <dt> <strong>Pmw.Color.changecolor</strong>(<em>widget</em>, <em>background</em> = <strong>None</strong>, **<em>kw</em>)</dt><dd> Change the color of <em>widget</em> 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 <strong>color scheme</strong> section. Any options which are different to the previous color scheme (or the defaults, if this is the first call) are not changed.</p> <p> For example to change a widget to have a red color scheme with a white foreground:</p> <dl><dd><pre> Pmw.Color.changecolor(widget, background = 'red3', foreground = 'white')</pre></dd></dl> <p> The colors of widgets created after this call will not be affected.</p> <p> Note that <em>widget</em> must be a Tk widget or toplevel. To change the color of a Pmw megawidget, use it's <strong>hull</strong> component. For example:</p> <dl><dd><pre> widget = megawidget.component('hull') Pmw.Color.changecolor(widget, background = 'red3')</pre></dd></dl> <p></p> </dd> <dt> <strong>Pmw.Color.correct</strong>(<em>rgb</em>, <em>correction</em>)</dt><dd> Return the "corrected" value of <em>rgb</em>. This can be used to correct for dull monitors. If <em>correction</em> is less than <strong>1.0</strong>, the color is dulled. If <em>correction</em> is greater than <strong>1.0</strong>, the color is brightened.</p> <p></p> </dd> <dt> <strong>Pmw.Color.getdefaultpalette</strong>(<em>root</em>)</dt><dd> Return a dictionary of the default values of the color options described in the <strong>color scheme</strong> section.</p> <p> To do this, a few widgets are created as children of <em>root</em>, their defaults are queried, and then the widgets are destroyed. (Tk supplies no other way to get widget default values.)</p> <p> Note that <em>root</em> must be a Tk widget or toplevel. To use a Pmw megawidget as the root, use it's <strong>hull</strong> component. For example:</p> <dl><dd><pre> root = megawidget.component('hull') Pmw.Color.getdefaultpalette(root)</pre></dd></dl> <p></p> </dd> <dt> <strong>Pmw.Color.hsi2rgb</strong>(<em>hue</em>, <em>saturation</em>, <em>intensity</em>)</dt><dd> Return the <strong>rgb</strong> representation of the color represented by <em>hue</em>, <em>saturation</em> and <em>intensity</em>.</p> <p></p> </dd> <dt> <strong>Pmw.Color.hue2name</strong>(<em>hue</em>, <em>brightness</em> = <strong>None</strong>)</dt><dd> Return the name of the color with the specified <em>hue</em> and <em>brightness</em>. If <em>hue</em> is <strong>None</strong>, return a grey of the requested brightness. Otherwise, the value of <em>hue</em> should be as described above. If <em>brightness</em> is <strong>None</strong>, return the name of color with the given hue and with saturation and intensity both <strong>1.0</strong>.</p> <p></p> </dd> <dt> <strong>Pmw.Color.name2rgb</strong>(<em>root</em>, <em>colorName</em>, <em>asInt</em> = <strong>0</strong>)</dt><dd> Return <em>colorName</em> as an <strong>rgb</strong> value. If <em>asInt</em> is true, then the elements of the return sequence are in the range <strong>0</strong> to <strong>65535</strong> rather than <strong>0.0</strong> to <strong>1.0</strong>. The <em>root</em> argument is only used to query Tk for the <strong>rgb</strong> values of <em>colorName</em>.</p> <p></p> </dd> <dt> <strong>Pmw.Color.rgb2brightness</strong>(<em>rgb</em>)</dt><dd> Return the brightness of the color represented by <em>rgb</em>.</p> <p></p> </dd> <dt> <strong>Pmw.Color.rgb2hsi</strong>(<em>rgb</em>)</dt><dd> Return a tuple (<em>hue</em>, <em>saturation</em>, <em>intensity</em>) corresponding to the color specified by the <em>rgb</em> sequence.</p> <p></p> </dd> <dt> <strong>Pmw.Color.rgb2name</strong>(<em>rgb</em>)</dt><dd> Return the name of the color represented by <em>rgb</em> as a string of the form <code>'#RRGGBB'</code> suitable for use with Tk color functions.</p> <p></p> </dd> <dt> <strong>Pmw.Color.setscheme</strong>(<em>root</em>, <em>background</em> = <strong>None</strong>, **<em>kw</em>)</dt><dd> Set the color scheme for the application by setting default colors (in the Tk option database of the root window of <em>root</em>) according to the color scheme specified by the other arguments. This will affect the initial colours of all widgets created after the call to this function.</p> <p> For example to initialise an application to have a red color scheme with a white foreground:</p> <dl><dd><pre> Pmw.Color.setscheme(root, background = 'red3', foreground = 'white')</pre></dd></dl> <p> This function does not modify the colors of already existing widgets. Use <strong>Pmw.Color.changecolor()</strong> to do this.</p> <p> Note that <em>root</em> must be a Tk widget or toplevel. To use the Tk option database of the root window of a Pmw megawidget, use the megawidget's <strong>hull</strong> component. For example:</p> <dl><dd><pre> root = megawidget.component('hull') Pmw.Color.setscheme(root, background = 'red3')</pre></dd></dl> <p></p> </dd> <dt> <strong>Pmw.Color.spectrum</strong>(<em>numColors</em>, <em>correction</em> = <strong>1.0</strong>, <em>saturation</em> = <strong>1.0</strong>, <em>intensity</em> = <strong>1.0</strong>, <em>extraOrange</em> = <strong>1</strong>, <em>returnHues</em> = <strong>0</strong>)</dt><dd> Return a list of <em>numColors</em> different colors making up a <em>spectrum</em>. If <em>extraOrange</em> is false, the colors are evenly spaced by hue from one end of the spectrum (red) to the other (magenta). If <em>extraOrange</em> is true, the hues are not quite evenly spaced - the hues around orange are emphasised, thus preventing the spectrum from appearing to have to many <em>cool</em> hues. </p> <p> If <em>returnHues</em> is false, the return values are the names of the colors represented by the hues together with <em>saturation</em> and <em>intensity</em> and corrected by <em>correction</em>.</p> <p> If <em>returnHues</em> is true, the return values are hues.</p> <p></p> </dd> </dl> </dd></dl> <center><P ALIGN="CENTER"> <IMG SRC = blue_line.gif ALT = "" WIDTH=320 HEIGHT=5> </p></center> <font size=-1> <center><P ALIGN="CENTER"> Pmw 1.1 - 26 Aug 2002 - <a href="index.html">Home</a> <br>Manual page last reviewed: 25 May 2002 </p></center> </font> </body> </html>