Detailed Description
The QGLColormap class is used for installing custom colormaps into
QGLWidgets.
QGLColormap provides a platform independent way of specifying and
installing indexed colormaps into QGLWidgets. 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.
Under Windows 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 explicit sharing (see Shared
Classes).
Example of use:
#include <qapplication.h>
#include <qglcolormap.h>
int main()
{
QApplication a( argc, argv );
MySuperGLWidget widget( 0 ); // 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 a.exec();
}
See also QGLWidget::setColormap(), QGLWidget::colormap(), Graphics Classes, and Image Processing Classes.
Member Function Documentation
QGLColormap::QGLColormap ()
Construct a QGLColormap.
QGLColormap::QGLColormap ( const QGLColormap & map )
Construct a shallow copy of map.
QGLColormap::~QGLColormap ()
Dereferences the QGLColormap and deletes it if this was the last
reference to it.
void QGLColormap::detach ()
Detaches this QGLColormap from the shared block.
QColor QGLColormap::entryColor ( int idx ) const
Returns the QRgb value in the colorcell with index idx.
QRgb QGLColormap::entryRgb ( int idx ) const
Returns the QRgb value in the colorcell with index idx.
int QGLColormap::find ( QRgb color ) const
Returns the index of the color color. If color is not in the
map, -1 is returned.
int QGLColormap::findNearest ( QRgb color ) const
Returns the index of the color that is the closest match to color
color.
bool QGLColormap::isEmpty () const
Returns TRUE if the colormap is empty; otherwise returns FALSE. A
colormap with no color values set is considered to be empty.
Assign a shallow copy of map to this QGLColormap.
void QGLColormap::setEntries ( int count, const QRgb * colors, int base = 0 )
Set an array of cells in this colormap. count is the number of
colors that should be set, colors is the array of colors, and
base is the starting index.
void QGLColormap::setEntry ( int idx, QRgb color )
Set cell at index idx in the colormap to color color.
void QGLColormap::setEntry ( int idx, const QColor & color )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Set the cell with index idx in the colormap to color color.
int QGLColormap::size () const
Returns the number of colorcells in the colormap.
This file is part of the Qt toolkit.
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