Hi,

Imagine you have this code:

import numpy as np

import matplotlib.cm as cm

import matplotlib.mlab as mlab

import matplotlib.pyplot as plt

delta = 0.25

x = y = np.arange(-3.0, 3.0, delta)

X, Y = np.meshgrid(x, y)

Z1 = mlab.bivariate_normal(X, Y, 1.0, 1.0, 0.0, 0.0)

Z2 = mlab.bivariate_normal(X, Y, 1.5, 0.5, 1, 1)

Z = Z2-Z1 # difference of Gaussians

plt.imshow(Z, interpolation='nearest', cmap=cm.gray, origin='lower', extent=[-3,3,-3,3])

Then you want to change the color of a few pixels to red.

You have a list of coordinates (i,j) and each pixel in this list should now be red.

I could play with masked arrays like in:

http://matplotlib.sourceforge.net/examples/pylab_examples/image_masked.html

but I would prefer a simple "display this pixel (i,j) in red whatever his value is" function.

Xavier