def _blit_regions(self, img, regions):
# Merge the regions into one big union of blit_once is True
if self._slices:
new_regions = []
for ((x, y), (w, h)) in regions:
new_regions.append( ((0, y), (img.width, h)), )
regions = new_regions
if self._blit_once:
region = regions.pop()
while regions:
region = rect.union(region, regions.pop())
regions = [region]
# It's the container's responsibility to apply children's alpha
# values. But there is no parent of the canvas to do that, so we
# do that here if it's necessary.
if self.alpha < 255:
if self._preserve_alpha:
self._backing_store_with_alpha.clear()
self._backing_store_with_alpha.blend(img, alpha = self.alpha)
else:
self._backing_store_with_alpha.draw_rectangle( (0, 0),
img.size,
(0, 0, 0, 255),
fill = True)
self._backing_store_with_alpha.blend(img, alpha = self.alpha,
merge_alpha = False)
img = self._backing_store_with_alpha
regions = rect.optimize_for_rendering(regions)
for r in regions:
# Clip rectangle to screen.
r = rect.intersect( r, ((0, 0), self.get_size()) )
if r == rect.empty:
continue
self._blit(img, r)
def _blit(self, img, r):
if self._update_rect:
self._update_rect = rect.union(r, self._update_rect)
else:
self._update_rect = r
