convert matplotlib colormap to Qt4 pixmap

cmap2pixmap.py

from matplotlib import cm
import numpy as np

from PyQt4.QtGui import QImage, QPixmap, QColor

def cmap2pixmap(cmap, steps=50):
    """Convert a maplotlib colormap into a QPixmap

    :param cmap: The colormap to use
    :type cmap: Matplotlib colormap instance (e.g. matplotlib.cm.gray)

    :param steps: The number of color steps in the output. Default=50
    :type steps: int

    :rtype: QPixmap
    """
    sm = cm.ScalarMappable(cmap=cmap)
    sm.norm.vmin = 0.0
    sm.norm.vmax = 1.0
    inds = np.linspace(0, 1, steps)
    rgbas = sm.to_rgba(inds)
    rgbas = [QColor(int(r * 255), int(g * 255),
                    int(b * 255), int(a * 255)).rgba() for r, g, b, a in rgbas]
    im = QImage(steps, 1, QImage.Format_Indexed8)
    im.setColorTable(rgbas)
    for i in range(steps):
        im.setPixel(i, 0, i)
    im = im.scaled(100, 100)
    pm = QPixmap.fromImage(im)
    return pm