diff --git a/Tests/test_file_gif.py b/Tests/test_file_gif.py index 69a1ee5be..45409cbc6 100644 --- a/Tests/test_file_gif.py +++ b/Tests/test_file_gif.py @@ -1,6 +1,6 @@ from .helper import unittest, PillowTestCase, hopper, netpbm_available -from PIL import Image, ImagePalette, GifImagePlugin +from PIL import Image, ImagePalette, GifImagePlugin, ImageDraw from io import BytesIO @@ -59,7 +59,7 @@ class TestFileGif(PillowTestCase): return len(test_file.getvalue()) self.assertEqual(test_grayscale(0), 800) - self.assertEqual(test_grayscale(1), 38) + self.assertEqual(test_grayscale(1), 44) self.assertEqual(test_bilevel(0), 800) self.assertEqual(test_bilevel(1), 800) @@ -318,6 +318,103 @@ class TestFileGif(PillowTestCase): img.seek(img.tell() + 1) self.assertEqual(img.disposal_method, i + 1) + def test_dispose2_palette(self): + 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)) + + # Red circle in center of each frame + d = ImageDraw.Draw(img) + d.ellipse([(40, 40), (60, 60)], fill=circle) + + im_list.append(img) + + 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") + + # Check top left pixel matches background + self.assertEqual(rgb_img.getpixel((0, 0)), (255, 0, 0)) + + # Center remains red every frame + self.assertEqual(rgb_img.getpixel((50, 50)), circle) + + def test_dispose2_diff(self): + 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)), + ] + + im_list = [] + for i in range(len(circles)): + # Transparent BG + img = Image.new("RGBA", (100, 100), (255, 255, 255, 0)) + + # Two circles per frame + d = ImageDraw.Draw(img) + d.ellipse([(0, 30), (40, 70)], fill=circles[i][0]) + d.ellipse([(60, 30), (100, 70)], fill=circles[i][1]) + + im_list.append(img) + + im_list[0].save( + 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") + + # Check left circle is correct colour + self.assertEqual(rgb_img.getpixel((20, 50)), colours[0]) + + # Check right circle is correct colour + self.assertEqual(rgb_img.getpixel((80, 50)), colours[1]) + + # 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 diff --git a/src/PIL/GifImagePlugin.py b/src/PIL/GifImagePlugin.py index b35420328..bbf1c603f 100644 --- a/src/PIL/GifImagePlugin.py +++ b/src/PIL/GifImagePlugin.py @@ -426,6 +426,7 @@ def _write_multiple_frames(im, fp, palette): im_frames = [] frame_count = 0 + 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 @@ -445,11 +446,22 @@ def _write_multiple_frames(im, fp, palette): if im_frames: # delta frame previous = im_frames[-1] - if _get_palette_bytes(im_frame) == _get_palette_bytes(previous["im"]): - delta = ImageChops.subtract_modulo(im_frame, previous["im"]) + 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_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"), previous["im"].convert("RGB") + im_frame.convert("RGB"), base_im.convert("RGB") ) bbox = delta.getbbox() if not bbox: @@ -683,10 +695,12 @@ def _get_color_table_size(palette_bytes): # calculate the palette size for the header import math - color_table_size = int(math.ceil(math.log(len(palette_bytes) // 3, 2))) - 1 - if color_table_size < 0: - color_table_size = 0 - return color_table_size + if not palette_bytes: + return 0 + elif len(palette_bytes) < 9: + return 1 + else: + return int(math.ceil(math.log(len(palette_bytes) // 3, 2))) - 1 def _get_header_palette(palette_bytes): @@ -717,6 +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""" @@ -736,14 +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)