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+#+title: Combining PyGame and PyCairo
+#&summary
+How to combine two Pythonic graphical frameworks
+#&
+#+license: wtf
+
+* Combining PyGame and PyCairo
+
+#&+classes=note
+See [[http://pygame.org/wiki/CairoPygame]] for other examples.
+#&
+
+This piece of code allows you to convert a Cairo surface to a PyGame
+surface. It also includes a small example on how to make SVG loading work. It
+works with Python 2.5+ and requires relatively recent versions of pygame,
+pycairo and NumPy to work. For the SVG example to work, you must also have rsvg
+installed.
+
+#+BEGIN_SRC python2
+#!/usr/bin/env python
+# Copyleft 2010 Niels Serup, WTFPL 2.0. Free software.
+
+### Imports ###
+import math
+import pygame
+import cairo
+import numpy
+import Image
+
+### Constants ###
+width, height = 640, 480
+
+
+### Functions ###
+def draw(ctx):
+    ctx.set_line_width(15)
+    ctx.arc(320, 240, 200, 0, 2 * math.pi)
+
+    #                   r    g  b    a
+    ctx.set_source_rgba(0.6, 0, 0.4, 1)
+    ctx.fill_preserve()
+
+    #                   r  g     b    a
+    ctx.set_source_rgba(0, 0.84, 0.2, 0.5)
+    ctx.stroke()
+
+def bgra_surf_to_rgba_string(cairo_surface):
+    # We use PIL to do this
+    img = Image.frombuffer(
+        'RGBA', (cairo_surface.get_width(),
+                 cairo_surface.get_height()),
+        cairo_surface.get_data(), 'raw', 'BGRA', 0, 1)
+
+    return img.tostring('raw', 'RGBA', 0, 1)
+
+
+### Body ###
+# Init PyGame
+pygame.display.init()
+screen = pygame.display.set_mode((width, height), 0, 32)
+
+# Create raw surface data (could also be done with something else than
+# NumPy)
+data = numpy.empty(width * height * 4, dtype=numpy.int8)
+
+# Create Cairo surface
+cairo_surface = cairo.ImageSurface.create_for_data(
+    data, cairo.FORMAT_ARGB32, width, height, width * 4)
+
+# Draw with Cairo on the surface
+ctx = cairo.Context(cairo_surface)
+draw(ctx)
+
+
+##### SVG LOADING EXAMPLE #####
+# Using rsvg it is possible to render an SVG file onto a Cairo
+# surface. Uncomment the following lines to make it work.
+#import rsvg # This will probably not work in Windows. As far as I
+# know, only GNU/Linux distibutions package this Python
+# module. Nevertheless, it should be easy to create a small wrapper;
+# see http://www.cairographics.org/cairo_rsvg_and_python_in_windows/
+
+# Load the file
+#svg_graphics = rsvg.Handle('path/to/file.svg')
+
+# Render the graphics onto your Cairo context
+#svg_graphics.render_cairo(ctx)
+
+# To get the SVG file's dimensions before you create a Cairo surface,
+# use the following function:
+#print svg_graphics.get_dimension_data()
+###############################
+
+# On little-endian machines (and perhaps big-endian, who knows?),
+# Cairo's ARGB format becomes a BGRA format. PyGame does not accept
+# BGRA, but it does accept RGBA, which is why we have to convert the
+# surface data. You can check what endian-type you have by printing
+# out sys.byteorder
+data_string = bgra_surf_to_rgba_string(cairo_surface)
+
+# Create PyGame surface
+pygame_surface = pygame.image.frombuffer(
+    data_string, (width, height), 'RGBA')
+
+# Show PyGame surface
+screen.blit(pygame_surface, (0,0))
+pygame.display.flip()
+
+clock = pygame.time.Clock()
+while not pygame.QUIT in [e.type for e in pygame.event.get()]:
+    clock.tick(30)
+#+END_SRC
+