SF.net SVN: matplotlib: [5672] trunk/matplotlib/doc/faq/howto_faq.rst

[<jd...@us...>]

Revision: 5672
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=5672&view=rev
Author:   jdh2358
Date:     2008-06-25 07:37:23 -0700 (Wed, 25 Jun 2008)

Log Message:
-----------
added transparent figure faq

Modified Paths:
--------------
    trunk/matplotlib/doc/faq/howto_faq.rst

Modified: trunk/matplotlib/doc/faq/howto_faq.rst
===================================================================
--- trunk/matplotlib/doc/faq/howto_faq.rst	2008-06-25 12:49:57 UTC (rev 5671)
+++ trunk/matplotlib/doc/faq/howto_faq.rst	2008-06-25 14:37:23 UTC (rev 5672)
@@ -6,7 +6,35 @@
 
 .. contents::
 
+.. _howto-transparent:
 
+How do I save transparent figures?
+==================================
+
+The :meth:`~matplotlib.pyplot.savefig` command has a keyword argument
+*transparent* which, if True, will make the figure and axes
+backgrounds transparent when saving, but will not affect the displayed
+image on the screen.  If you need finer grained control, eg you do not
+want full transparency or you to affect the screen displayed version
+as well, you can set the alpha properties directly.  The figure has a
+:class:`matplotlib.patches.Rectangle` instance called *figurePatch*
+and the axes has a Rectangle instance called *axesPatch*.  You can set
+any property on them directly (*facecolor*, *edgecolor*, *linewidth*,
+*linestyle*, *alpha*).  Eg::
+
+    fig = plt.figure()
+    fig.figurePatch.set_alpha(0.5)
+    ax = fig.add_subplot(111)
+    ax.axesPatch.set_alpha(0.5)
+
+If you need *all* the figure elements to be transparent, there is
+currently no global alpha setting, but you can set the alpha channel
+on individual elements, eg::
+
+   ax.plot(x, y, alpha=0.5)
+   ax.set_xlabel('volts', alpha=0.5)
+
+
 .. _howto-subplots-adjust:
 
 How do I move the edge of my axes area over to make room for my tick labels?


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