Partially transparent scatter plot, but with a solid color bar

Question

In Python, with Matplotlib, how to simply do a scatter plot with transparency (alpha < 1), but with a color bar that represents their color value, but has alpha = 1?

Here is what one gets, with from pylab import *; scatter(range(10), arange(0, 100, 10), c=range(10), alpha=0.2); color_bar = colorbar():

How can the color bar be made non-transparent?

PS: I tried color_bar.set_alpha(1); draw(), but this did not do anything…

Answer 1

Alright, I found one way to do it, that looks relatively clean: (using the ColorBar object from the question)

color_bar.set_alpha(1) color_bar.draw_all() # pylab.draw() or pyplot.draw() might be necessary 

It would be great to get a confirmation that this is the most robust way to proceed, though! :)

Answer 2

This is a huge, ugly hack. But no other way would work. Maybe someone else can improve.

fig1 = pylab.figure() fig2 = pylab.figure() ax1 = fig1.add_subplot(111) ax2 = fig2.add_subplot(111) ax1.scatter(range(10), range(10), c=range(10), alpha=0.2) im = ax2.scatter(range(10), range(10), c=range(10), alpha=1.0) fig1.colorbar(im, ax=ax1) fig1.show()