Unified different GIF optimize conditions

This commit is contained in:
Andrew Murray 2016-11-05 13:32:02 +11:00
parent 5aeb0ed972
commit a51dc7dcaf

View File

@ -434,18 +434,16 @@ def _get_local_header(fp, im, offset, flags):
# optimize the block away if transparent color is not used
transparent_color_exists = True
if _get_optimize(im, im.encoderinfo):
used_palette_colors = _get_used_palette_colors(im)
used_palette_colors = _get_optimize(im, im.encoderinfo)
if used_palette_colors is not None:
# adjust the transparency index after optimize
if len(used_palette_colors) < 256:
for i in range(len(used_palette_colors)):
if used_palette_colors[i] == transparency:
transparency = i
transparent_color_exists = True
break
else:
transparent_color_exists = False
for i in range(len(used_palette_colors)):
if used_palette_colors[i] == transparency:
transparency = i
transparent_color_exists = True
break
else:
transparent_color_exists = False
if "duration" in im.encoderinfo:
duration = int(im.encoderinfo["duration"] / 10)
@ -552,9 +550,28 @@ def _save_netpbm(im, fp, filename):
# --------------------------------------------------------------------
# GIF utilities
def _get_optimize(im, info):
return im.mode in ("P", "L") and info and info.get("optimize", 0)
# Force optimization so that we can test performance against
# cases where it took lots of memory and time previously.
_FORCE_OPTIMIZE = False
def _get_optimize(im, info):
if im.mode in ("P", "L") and info and info.get("optimize", 0):
# Potentially expensive operation.
# The palette saves 3 bytes per color not used, but palette
# lengths are restricted to 3*(2**N) bytes. Max saving would
# be 768 -> 6 bytes if we went all the way down to 2 colors.
# * If we're over 128 colors, we can't save any space.
# * If there aren't any holes, it's not worth collapsing.
# * If we have a 'large' image, the palette is in the noise.
# create the new palette if not every color is used
used_palette_colors = _get_used_palette_colors(im)
if _FORCE_OPTIMIZE or im.mode == 'L' or \
(len(used_palette_colors) <= 128 and
max(used_palette_colors) > len(used_palette_colors) and
im.width * im.height < 512 * 512):
return used_palette_colors
def _get_used_palette_colors(im):
used_palette_colors = []
@ -586,10 +603,6 @@ def _get_header_palette(palette_bytes):
palette_bytes += o8(0) * 3 * actual_target_size_diff
return palette_bytes
# Force optimization so that we can test performance against
# cases where it took lots of memory and time previously.
_FORCE_OPTIMIZE = False
def _get_palette_bytes(im, palette, info):
if im.mode == "P":
if palette and isinstance(palette, bytes):
@ -602,79 +615,64 @@ def _get_palette_bytes(im, palette, info):
else:
source_palette = bytearray([i//3 for i in range(768)])
used_palette_colors = palette_bytes = None
palette_bytes = None
if _get_optimize(im, info):
used_palette_colors = _get_used_palette_colors(im)
used_palette_colors = _get_optimize(im, info)
if used_palette_colors is not None:
palette_bytes = b""
new_positions = [0]*256
# Potentially expensive operation.
# pick only the used colors from the palette
for i, oldPosition in enumerate(used_palette_colors):
palette_bytes += source_palette[oldPosition*3:oldPosition*3+3]
new_positions[oldPosition] = i
# The palette saves 3 bytes per color not used, but palette
# lengths are restricted to 3*(2**N) bytes. Max saving would
# be 768 -> 6 bytes if we went all the way down to 2 colors.
# * If we're over 128 colors, we can't save any space.
# * If there aren't any holes, it's not worth collapsing.
# * If we have a 'large' image, the palette is in the noise.
# replace the palette color id of all pixel with the new id
# create the new palette if not every color is used
if _FORCE_OPTIMIZE or im.mode == 'L' or \
(len(used_palette_colors) <= 128 and
max(used_palette_colors) > len(used_palette_colors) and
im.width * im.height < 512 * 512):
palette_bytes = b""
new_positions = [0]*256
# Palette images are [0..255], mapped through a 1 or 3
# byte/color map. We need to remap the whole image
# from palette 1 to palette 2. New_positions is
# an array of indexes into palette 1. Palette 2 is
# palette 1 with any holes removed.
# pick only the used colors from the palette
for i, oldPosition in enumerate(used_palette_colors):
palette_bytes += source_palette[oldPosition*3:oldPosition*3+3]
new_positions[oldPosition] = i
# We're going to leverage the convert mechanism to use the
# C code to remap the image from palette 1 to palette 2,
# by forcing the source image into 'L' mode and adding a
# mapping 'L' mode palette, then converting back to 'L'
# sans palette thus converting the image bytes, then
# assigning the optimized RGB palette.
# replace the palette color id of all pixel with the new id
# perf reference, 9500x4000 gif, w/~135 colors
# 14 sec prepatch, 1 sec postpatch with optimization forced.
# Palette images are [0..255], mapped through a 1 or 3
# byte/color map. We need to remap the whole image
# from palette 1 to palette 2. New_positions is
# an array of indexes into palette 1. Palette 2 is
# palette 1 with any holes removed.
mapping_palette = bytearray(new_positions)
# We're going to leverage the convert mechanism to use the
# C code to remap the image from palette 1 to palette 2,
# by forcing the source image into 'L' mode and adding a
# mapping 'L' mode palette, then converting back to 'L'
# sans palette thus converting the image bytes, then
# assigning the optimized RGB palette.
m_im = im.copy()
m_im.mode = 'P'
# perf reference, 9500x4000 gif, w/~135 colors
# 14 sec prepatch, 1 sec postpatch with optimization forced.
m_im.palette = ImagePalette.ImagePalette("RGB",
palette=mapping_palette*3,
size=768)
#possibly set palette dirty, then
#m_im.putpalette(mapping_palette, 'L') # converts to 'P'
# or just force it.
# UNDONE -- this is part of the general issue with palettes
m_im.im.putpalette(*m_im.palette.getdata())
mapping_palette = bytearray(new_positions)
m_im = m_im.convert('L')
m_im = im.copy()
m_im.mode = 'P'
# Internally, we require 768 bytes for a palette.
new_palette_bytes = (palette_bytes +
(768 - len(palette_bytes)) * b'\x00')
m_im.putpalette(new_palette_bytes)
m_im.palette = ImagePalette.ImagePalette("RGB",
palette=palette_bytes,
size=len(palette_bytes))
m_im.palette = ImagePalette.ImagePalette("RGB",
palette=mapping_palette*3,
size=768)
#possibly set palette dirty, then
#m_im.putpalette(mapping_palette, 'L') # converts to 'P'
# or just force it.
# UNDONE -- this is part of the general issue with palettes
m_im.im.putpalette(*m_im.palette.getdata())
m_im = m_im.convert('L')
# Internally, we require 768 bytes for a palette.
new_palette_bytes = (palette_bytes +
(768 - len(palette_bytes)) * b'\x00')
m_im.putpalette(new_palette_bytes)
m_im.palette = ImagePalette.ImagePalette("RGB",
palette=palette_bytes,
size=len(palette_bytes))
# oh gawd, this is modifying the image in place so I can pass by ref.
# REFACTOR SOONEST
im.frombytes(m_im.tobytes())
# oh gawd, this is modifying the image in place so I can pass by ref.
# REFACTOR SOONEST
im.frombytes(m_im.tobytes())
if not palette_bytes:
palette_bytes = source_palette