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#!/usr/bin/env python
"""test cairo.ImageSurface.create_for_data() with a numpy array
"""
import tempfile
import cairo
import numpy
if not (cairo.HAS_IMAGE_SURFACE and cairo.HAS_PNG_FUNCTIONS):
raise SystemExit ('cairo was not compiled with ImageSurface and PNG support')
h, fileName = tempfile.mkstemp(prefix='pycairo_', suffix='.png')
width, height = 255, 255
data = numpy.ndarray (shape=(height,width,4), dtype=numpy.uint8)
for x in range(width):
for y in range(height):
alpha = y
# cairo.FORMAT_ARGB32 uses pre-multiplied alpha
data[y][x][0] = int(x * alpha/255.0) # B
data[y][x][1] = int(y * alpha/255.0) # G
data[y][x][2] = 0 # R
data[y][x][3] = alpha # A
surface = cairo.ImageSurface.create_for_data (data, cairo.FORMAT_ARGB32,
width, height)
ctx = cairo.Context(surface)
surface.write_to_png(fileName)
print "see %s output file" % fileName
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