Do not presume that the background color index is 0

This commit is contained in:
Andrew Murray 2019-06-29 23:06:45 +10:00
parent 97c15a245c
commit 90d3d37164
2 changed files with 63 additions and 37 deletions

View File

@ -319,14 +319,14 @@ class TestFileGif(PillowTestCase):
self.assertEqual(img.disposal_method, i + 1)
def test_dispose2_palette(self):
out = self.tempfile('temp.gif')
out = self.tempfile("temp.gif")
# 4 backgrounds: White, Grey, Black, Red
circles = [(255, 255, 255), (153, 153, 153), (0, 0, 0), (255, 0, 0)]
im_list = []
for circle in circles:
img = Image.new('RGB', (100, 100), (255, 0, 0))
img = Image.new("RGB", (100, 100), (255, 0, 0))
# Red circle in center of each frame
d = ImageDraw.Draw(img)
@ -334,18 +334,13 @@ class TestFileGif(PillowTestCase):
im_list.append(img)
im_list[0].save(
out,
save_all=True,
append_images=im_list[1:],
disposal=2
)
im_list[0].save(out, save_all=True, append_images=im_list[1:], disposal=2)
img = Image.open(out)
for i, circle in enumerate(circles):
img.seek(i)
rgb_img = img.convert('RGB')
rgb_img = img.convert("RGB")
# Check top left pixel matches background
self.assertEqual(rgb_img.getpixel((0, 0)), (255, 0, 0))
@ -354,20 +349,20 @@ class TestFileGif(PillowTestCase):
self.assertEqual(rgb_img.getpixel((50, 50)), circle)
def test_dispose2_diff(self):
out = self.tempfile('temp.gif')
out = self.tempfile("temp.gif")
# 4 frames: red/blue, red/red, blue/blue, red/blue
circles = [
((255, 0, 0, 255), (0, 0, 255, 255)),
((255, 0, 0, 255), (255, 0, 0, 255)),
((0, 0, 255, 255), (0, 0, 255, 255)),
((255, 0, 0, 255), (0, 0, 255, 255))
((255, 0, 0, 255), (0, 0, 255, 255)),
]
im_list = []
for i in range(len(circles)):
# Transparent BG
img = Image.new('RGBA', (100, 100), (255, 255, 255, 0))
img = Image.new("RGBA", (100, 100), (255, 255, 255, 0))
# Two circles per frame
d = ImageDraw.Draw(img)
@ -377,18 +372,14 @@ class TestFileGif(PillowTestCase):
im_list.append(img)
im_list[0].save(
out,
save_all=True,
append_images=im_list[1:],
disposal=2,
transparency=0
out, save_all=True, append_images=im_list[1:], disposal=2, transparency=0
)
img = Image.open(out)
for i, colours in enumerate(circles):
img.seek(i)
rgb_img = img.convert('RGBA')
rgb_img = img.convert("RGBA")
# Check left circle is correct colour
self.assertEqual(rgb_img.getpixel((20, 50)), colours[0])
@ -399,6 +390,31 @@ class TestFileGif(PillowTestCase):
# Check BG is correct colour
self.assertEqual(rgb_img.getpixel((1, 1)), (255, 255, 255, 0))
def test_dispose2_background(self):
out = self.tempfile("temp.gif")
im_list = []
im = Image.new("P", (100, 100))
d = ImageDraw.Draw(im)
d.rectangle([(50, 0), (100, 100)], fill="#f00")
d.rectangle([(0, 0), (50, 100)], fill="#0f0")
im_list.append(im)
im = Image.new("P", (100, 100))
d = ImageDraw.Draw(im)
d.rectangle([(0, 0), (100, 50)], fill="#f00")
d.rectangle([(0, 50), (100, 100)], fill="#0f0")
im_list.append(im)
im_list[0].save(
out, save_all=True, append_images=im_list[1:], disposal=[0, 2], background=1
)
im = Image.open(out)
im.seek(1)
self.assertEqual(im.getpixel((0, 0)), 0)
def test_iss634(self):
img = Image.open("Tests/images/iss634.gif")
# seek to the second frame

View File

@ -426,9 +426,8 @@ def _write_multiple_frames(im, fp, palette):
im_frames = []
frame_count = 0
background = None
for imSequence in itertools.chain([im],
im.encoderinfo.get("append_images", [])):
background_im = None
for imSequence in itertools.chain([im], im.encoderinfo.get("append_images", [])):
for im_frame in ImageSequence.Iterator(imSequence):
# a copy is required here since seek can still mutate the image
im_frame = _normalize_mode(im_frame.copy())
@ -447,16 +446,23 @@ def _write_multiple_frames(im, fp, palette):
if im_frames:
# delta frame
previous = im_frames[-1]
if disposal == 2:
base_image = background
if encoderinfo.get("disposal") == 2:
if background_im is None:
background = _get_background(
im,
im.encoderinfo.get("background", im.info.get("background")),
)
background_im = Image.new("P", im_frame.size, background)
background_im.putpalette(im_frames[0]["im"].palette)
base_im = background_im
else:
base_image = previous["im"]
if _get_palette_bytes(im_frame) == _get_palette_bytes(base_frame):
delta = ImageChops.subtract_modulo(im_frame, base_image)
base_im = previous["im"]
if _get_palette_bytes(im_frame) == _get_palette_bytes(base_im):
delta = ImageChops.subtract_modulo(im_frame, base_im)
else:
delta = ImageChops.subtract_modulo(
im_frame.convert("RGB"), base_image.convert("RGB"))
im_frame.convert("RGB"), base_im.convert("RGB")
)
bbox = delta.getbbox()
if not bbox:
# This frame is identical to the previous frame
@ -465,7 +471,6 @@ def _write_multiple_frames(im, fp, palette):
continue
else:
bbox = None
background = Image.new("P", im_frame.size, 0)
im_frames.append({"im": im_frame, "bbox": bbox, "encoderinfo": encoderinfo})
if len(im_frames) > 1:
@ -726,6 +731,18 @@ def _get_palette_bytes(im):
return im.palette.palette
def _get_background(im, infoBackground):
background = 0
if infoBackground:
background = infoBackground
if isinstance(background, tuple):
# WebPImagePlugin stores an RGBA value in info["background"]
# So it must be converted to the same format as GifImagePlugin's
# info["background"] - a global color table index
background = im.palette.getcolor(background)
return background
def _get_global_header(im, info):
"""Return a list of strings representing a GIF header"""
@ -745,14 +762,7 @@ def _get_global_header(im, info):
if im.info.get("version") == b"89a":
version = b"89a"
background = 0
if "background" in info:
background = info["background"]
if isinstance(background, tuple):
# WebPImagePlugin stores an RGBA value in info["background"]
# So it must be converted to the same format as GifImagePlugin's
# info["background"] - a global color table index
background = im.palette.getcolor(background)
background = _get_background(im, info.get("background"))
palette_bytes = _get_palette_bytes(im)
color_table_size = _get_color_table_size(palette_bytes)