Qt Documentation

QGLColormap¶

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

Synopsis¶

Functions¶

def entryColor (idx)
def entryRgb (idx)
def find (color)
def findNearest (color)
def handle ()
def isEmpty ()
def setEntry (idx, color)
def setEntry (idx, color)
def setHandle (ahandle)
def size ()

Detailed Description¶

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:
import sys

from PySide2.QtGui import QApplication, qRgb
from PySide2.QtOpenGL import QGLColormap

def main(argv):
    app = QApplication(argv)

    widget = MySuperGLWidget()     # a QGLWidget in color-index mode
    colormap = QGLColormap()

    # This will fill the colormap with colors ranging from
    # black to white.
    for i in range(0, colormap.size()):
        colormap.setEntry(i, qRgb(i, i, i))

    widget.setColormap(colormap)
    widget.show()
    return app.exec_()

if __name__ == "__main__":
    main(sys.argv)
See also

setColormap() colormap()

class QGLColormap¶

QGLColormap(arg__1)

param arg__1

QGLColormap

Construct a QGLColormap .

Construct a shallow copy of map .

PySide2.QtOpenGL.QGLColormap.entryColor(idx)¶

Parameters: idx – int
Return type: QColor

Returns the QRgb value in the colorcell with index idx .

PySide2.QtOpenGL.QGLColormap.entryRgb(idx)¶

Parameters: idx – int
Return type: long

Returns the QRgb value in the colorcell with index idx .

PySide2.QtOpenGL.QGLColormap.find(color)¶

Parameters: color – long
Return type: int

Returns the index of the color color . If color is not in the map, -1 is returned.

PySide2.QtOpenGL.QGLColormap.findNearest(color)¶

Parameters: color – long
Return type: int

Returns the index of the color that is the closest match to color color .

PySide2.QtOpenGL.QGLColormap.handle()¶

Return type: HANDLE

Returns the handle for this color map.

PySide2.QtOpenGL.QGLColormap.isEmpty()¶

Return type: bool

Returns true if the colormap is empty or it is not in use by a QGLWidget ; otherwise returns false .

A colormap with no color values set is considered to be empty. For historical reasons, a colormap that has color values set but which is not in use by a QGLWidget is also considered empty.

Compare size() with zero to determine if the colormap is empty regardless of whether it is in use by a QGLWidget or not.