def _create_bitmap_context(self, width, height):
'''Create or recreate bitmap and Quartz context.'''
if self._bitmap_context:
carbon.CGContextRelease(self._bitmap_context)
components = 4
pitch = width * components
self._bitmap = (c_ubyte * (pitch * height))()
color_space = carbon.CGColorSpaceCreateDeviceRGB()
context = carbon.CGBitmapContextCreate(self._bitmap, width, height, 8,
pitch, color_space,
kCGImageAlphaPremultipliedLast)
carbon.CGColorSpaceRelease(color_space)
# Disable RGB decimated antialiasing, use standard
# antialiasing which won't break alpha.
carbon.CGContextSetShouldSmoothFonts(context, False)
carbon.CGContextSetShouldAntialias(context, True)
self._bitmap_context = context
self._bitmap_rect = CGRect()
self._bitmap_rect.origin.x = 0
self._bitmap_rect.origin.y = 0
self._bitmap_rect.size.width = width
self._bitmap_rect.size.height = height
def __del__(self):
try:
if self._bitmap_context:
carbon.CGContextRelease(self._bitmap_context)
except:
pass
def __del__(self):
if self._bitmap_context:
carbon.CGContextRelease(self._bitmap_context)