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

详细描述

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 隐式共享 as a memory and speed optimization.

用法范例：

#include <QApplication>
#include <QGLColormap>
int main(int argc, char *argv[])
{
    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.
    const int size = 256;
    for (int i = 0; i < size; ++i)
        colormap.setEntry(i, qRgb(i, i, i));
    widget.setColormap(colormap);
    widget.show();
    return app.exec();
}
							

另请参阅 QGLWidget::setColormap () 和 QGLWidget::colormap ().