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