QGLColormap Class Reference
[QtOpenGL module]

Detailed Description

The QGLColormap class is used for installing custom colormaps into a QGLWidget.

QGLColormap provides a platform independent way of specifying and installing indexed colormaps for a QGLWidget. QGLColormap is especially useful when using the OpenGL color-index mode.

Under X11 you must use an X server that supports either a PseudoColor or DirectColor visual class. If your X server currently only provides a GrayScale, TrueColor, StaticColor or StaticGray visual, you will not be able to allocate colorcells for writing. If this is the case, try setting your X server to 8 bit mode. It should then provide you with at least a PseudoColor visual. Note that you may experience colormap flashing if your X server is running in 8 bit mode.

The size() of the colormap is always set to 256 colors. Note that under Windows you can also install colormaps in child widgets.

This class uses implicit sharing as a memory and speed optimization.

Example of use:

 #include <QApplication>
 #include <QGLColormap>

 int main()
 {
     QApplication app(argc, argv);

     MySuperGLWidget widget;     // a QGLWidget in color-index mode
     QGLColormap colormap;

     // This will fill the colormap with colors ranging from
     // black to white.
     for (int i = 0; i < colormap.size(); i++)
         colormap.setEntry(i, qRgb(i, i, i));

     widget.setColormap(colormap);
     widget.show();
     return app.exec();
 }

See also QGLWidget::setColormap() and QGLWidget::colormap().

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