Use 1 and not P for basic 1bpp BMP

Readapted some original code.
This commit is contained in:
artscoop 2015-03-05 08:19:14 +01:00
parent 56439b728f
commit 934651427d

View File

@ -23,13 +23,12 @@
# See the README file for information on usage and redistribution. # See the README file for information on usage and redistribution.
# #
__version__ = "0.7" __version__ = "0.7"
from PIL import Image, ImageFile, ImagePalette, _binary from PIL import Image, ImageFile, ImagePalette, _binary
import math import math
i8 = _binary.i8 i8 = _binary.i8
i16 = _binary.i16le i16 = _binary.i16le
i32 = _binary.i32le i32 = _binary.i32le
@ -56,131 +55,147 @@ def _accept(prefix):
return prefix[:2] == b"BM" return prefix[:2] == b"BM"
## #===============================================================================
# Image plugin for the Windows BMP format. # Image plugin for the Windows BMP format.
#===============================================================================
class BmpImageFile(ImageFile.ImageFile): class BmpImageFile(ImageFile.ImageFile):
""" Image plugin for the Windows Bitmap format (BMP) """
format = "BMP" #--------------------------------------------------------------- Description
format_description = "Windows Bitmap" format_description = "Windows Bitmap"
format = "BMP"
def _bitmap(self, header=0, offset=0): #---------------------------------------------------- BMP Compression values
if header: COMPRESSIONS = {'RAW': 0, 'RLE8': 1, 'RLE4': 2, 'BITFIELDS': 3, 'JPEG': 4, 'PNG': 5}
self.fp.seek(header) RAW, RLE8, RLE4, BITFIELDS, JPEG, PNG = 0, 1, 2, 3, 4, 5
read = self.fp.read
# CORE/INFO
s = read(4)
s = s + ImageFile._safe_read(self.fp, i32(s)-4)
if len(s) == 12:
# OS/2 1.0 CORE
bits = i16(s[10:])
self.size = i16(s[4:]), i16(s[6:])
compression = 0
lutsize = 3
colors = 0
direction = -1
elif len(s) in [40, 64, 108, 124]:
# WIN 3.1 or OS/2 2.0 INFO
bits = i16(s[14:])
self.size = i32(s[4:]), i32(s[8:])
compression = i32(s[16:])
pxperm = (i32(s[24:]), i32(s[28:])) # Pixels per meter
lutsize = 4
colors = i32(s[32:])
direction = -1
if i8(s[11]) == 0xff:
# upside-down storage
self.size = self.size[0], 2**32 - self.size[1]
direction = 0
self.info["dpi"] = tuple(map(lambda x: math.ceil(x / 39.3701),
pxperm))
else:
raise IOError("Unsupported BMP header type (%d)" % len(s))
if (self.size[0]*self.size[1]) > 2**31:
# Prevent DOS for > 2gb images
raise IOError("Unsupported BMP Size: (%dx%d)" % self.size)
if not colors:
colors = 1 << bits
# MODE
try:
self.mode, rawmode = BIT2MODE[bits]
except KeyError:
raise IOError("Unsupported BMP pixel depth (%d)" % bits)
if compression == 3:
# BI_BITFIELDS compression
mask = i32(read(4)), i32(read(4)), i32(read(4))
if bits == 32 and mask == (0xff0000, 0x00ff00, 0x0000ff):
rawmode = "BGRX"
elif bits == 16 and mask == (0x00f800, 0x0007e0, 0x00001f):
rawmode = "BGR;16"
elif bits == 16 and mask == (0x007c00, 0x0003e0, 0x00001f):
rawmode = "BGR;15"
else:
# print bits, map(hex, mask)
raise IOError("Unsupported BMP bitfields layout")
elif compression != 0:
raise IOError("Unsupported BMP compression (%d)" % compression)
# LUT
if self.mode == "P":
palette = []
greyscale = 1
if colors == 2:
indices = (0, 255)
elif colors > 2**16 or colors <= 0: # We're reading a i32.
raise IOError("Unsupported BMP Palette size (%d)" % colors)
else:
indices = list(range(colors))
for i in indices:
rgb = read(lutsize)[:3]
if rgb != o8(i)*3:
greyscale = 0
palette.append(rgb)
if greyscale:
if colors == 2:
self.mode = rawmode = "1"
else:
self.mode = rawmode = "L"
else:
self.mode = "P"
self.palette = ImagePalette.raw(
"BGR", b"".join(palette)
)
if not offset:
offset = self.fp.tell()
self.tile = [("raw",
(0, 0) + self.size,
offset,
(rawmode, ((self.size[0]*bits+31) >> 3) & (~3),
direction))]
self.info["compression"] = compression
def _open(self): def _open(self):
""" Open file, check magic number and read header """
# HEAD # read 14 bytes: magic number, filesize, reserved, header final offset
s = self.fp.read(14) head_data = self.fp.read(14)
if s[:2] != b"BM": # choke if the file does not have the required magic bytes
raise SyntaxError("Not a BMP file") if head_data[0:2] != b"BM":
offset = i32(s[10:]) raise SyntaxError("Expected a BMP file.")
# read the start position of the BMP image data (u32)
offset = i32(head_data[10:14])
# load bitmap information (offset=raster info)
self._bitmap(offset=offset) self._bitmap(offset=offset)
def _bitmap(self, header=0, offset=0):
""" Read relevant info about the BMP """
read, seek = self.fp.read, self.fp.seek
seek(2)
start_data = read(12)
file_info = dict()
file_info['filesize'] = i32(start_data[0:4]) # file size @offset 2 (offsets 4, 12 are reserved for OS/2 Icons)
file_info['image_offset'] = i32(start_data[8:12]) # file size @offset 2 (offsets 4, 12 are reserved for OS/2 Icons)
file_info['header_size'] = i32(read(4)) # read bmp header size @offset 14 (this is part of the header size)
file_info['direction'] = -1
header_data = ImageFile._safe_read(self.fp, file_info['header_size'] - 4) # read the rest of the bmp header, without its size
#---------------------------------------------------- IBM OS/2 Bitmap v1
#------- This format has different offsets because of width/height types
if file_info['header_size'] == 12:
file_info['width'] = i16(header_data[0:2])
file_info['height'] = i16(header_data[2:4])
file_info['planes'] = i16(header_data[4:6])
file_info['bits'] = i16(header_data[6:8])
file_info['compression'] = self.RAW
file_info['palette_padding'] = 3
#----------------------------------------------- Windows Bitmap v2 to v5
elif file_info['header_size'] in {40, 64, 108, 124}: # v3, OS/2 v2, v4, v5
if file_info['header_size'] >= 64:
file_info['r_mask'] = i32(header_data[36:40])
file_info['g_mask'] = i32(header_data[40:44])
file_info['b_mask'] = i32(header_data[44:48])
file_info['a_mask'] = i32(header_data[48:52])
file_info['rgb_mask'] = (file_info['r_mask'], file_info['g_mask'], file_info['b_mask'])
file_info['rgba_mask'] = (file_info['r_mask'], file_info['g_mask'], file_info['b_mask'], file_info['a_mask'])
if file_info['header_size'] >= 40: # v3 and OS/2
file_info['y_flip'] = i8(header_data[7]) == 0xff
file_info['direction'] = 1 if file_info['y_flip'] else -1
file_info['width'] = i32(header_data[0:4])
file_info['height'] = i32(header_data[4:8]) if not file_info['y_flip'] else 2**32 - i32(header_data[4:8])
file_info['planes'] = i16(header_data[8:10])
file_info['bits'] = i16(header_data[10:12])
file_info['compression'] = i32(header_data[12:16])
file_info['data_size'] = i32(header_data[16:20]) # byte size of pixel data
file_info['pixels_per_meter'] = (i32(header_data[20:24]), i32(header_data[24:28]))
file_info['colors'] = i32(header_data[28:32])
file_info['palette_padding'] = 4
#------------------- Special case : header is reported 40, which
#----------------------- is shorter than real size for bpp >= 16
if file_info['header_size'] < 64 and file_info['bits'] >= 16:
file_info['r_mask'] = i32(read(4))
file_info['g_mask'] = i32(read(4))
file_info['b_mask'] = i32(read(4))
file_info['a_mask'] = i32(read(4))
file_info['rgb_mask'] = (file_info['r_mask'], file_info['g_mask'], file_info['b_mask'])
file_info['rgba_mask'] = (file_info['r_mask'], file_info['g_mask'], file_info['b_mask'], file_info['a_mask'])
self.info["dpi"] = tuple(map(lambda x: math.ceil(x / 39.3701), file_info['pixels_per_meter']))
else:
raise IOError("BMP images with a {0} byte header are not supported".format(file_info['header_size']))
self.size = file_info['width'], file_info['height']
#--------- If color count was not found in the header, compute from bits
file_info['colors'] = file_info['colors'] if file_info.get('colors', 0) else (1 << file_info['bits'])
#--------------------------------- Check abnormal values for DOS attacks
if file_info['width'] * file_info['height'] > 2**31:
raise IOError("BMP images with more than 2 billion pixels are not supported (here {0} pixels)".format(file_info['width'] * file_info['height']))
#------------------------ Check bit depth for unusual unsupported values
self.mode, raw_mode = BIT2MODE.get(file_info['bits'], (None, None))
if self.mode is None:
raise IOError("BMP images with a {0}-bit pixel depth are not supported".format(file_info['bits']))
#------------------ Process BMP with Bitfields compression (not palette)
if file_info['compression'] == self.BITFIELDS:
SUPPORTED = {32: [(0xff0000, 0xff00, 0xff, 0x0), (0xff0000, 0xff00, 0xff, 0xff000000)], 24: [(0xff0000, 0xff00, 0xff)], 16: [(0xf800, 0x7e0, 0x1f), (0x7c00, 0x3e0, 0x1f)]}
MASK_MODES = {(32, (0xff0000, 0xff00, 0xff, 0x0)): "BGRX", (32, (0xff0000, 0xff00, 0xff, 0xff000000)): "BGRA", (24, (0xff0000, 0xff00, 0xff)): "BGR", (16, (0xf800, 0x7e0, 0x1f)): "BGR;16", (16, (0x7c00, 0x3e0, 0x1f)): "BGR;15"}
if file_info['bits'] in SUPPORTED:
if file_info['bits'] == 32 and file_info['rgba_mask'] in SUPPORTED[file_info['bits']]:
raw_mode = MASK_MODES[(file_info['bits'], file_info['rgba_mask'])]
self.mode = "RGBA" if raw_mode in ("BGRA",) else self.mode
elif file_info['bits'] in (24, 16) and file_info['rgb_mask'] in SUPPORTED[file_info['bits']]:
raw_mode = MASK_MODES[(file_info['bits'], file_info['rgb_mask'])]
else:
raise IOError("BMP images with the provided bitfield mask are not supported")
else:
raise IOError("BMP images with the provided bitfield information are not supported")
elif file_info['compression'] != self.RAW:
raise IOError("BMP files with RLE (1/2), JPEG (4) and PNG (5) compression are not supported")
#----------------- Once the header is processed, process the palette/LUT
if self.mode == "P": # Paletted for 1, 4 and 8 bit images
#------------------------------------------------------ 1-bit images
if not (0 < file_info['colors'] <= 65536):
raise IOError("BMP palette must have between 1 and 256 colors")
else:
padding = file_info['palette_padding']
palette = read(padding * file_info['colors'])
greyscale = True
indices = (0, 255) if file_info['colors'] == 2 else list(range(file_info['colors']))
#------------------- Check if greyscale and ignore palette if so
for ind, val in enumerate(indices):
rgb = palette[ind*padding:ind*padding + 3]
if rgb != o8(val) * 3:
greyscale = False
#--------- If all colors are grey, white or black, ditch palette
if greyscale:
self.mode = "1" if file_info['colors'] == 2 else "L"
raw_mode = self.mode
else:
self.mode = "P"
self.palette = ImagePalette.raw("BGRX" if padding == 4 else "BGR", b"".join(palette))
#------------------------------ Finally set the tile data for the plugin
self.info['compression'] = file_info['compression']
self.tile = [('raw', (0, 0, file_info['width'], file_info['height']), file_info['image_offset'],
(raw_mode, ((file_info['width'] * file_info['bits'] + 31) >> 3) & (~3), file_info['direction'])
)]
#===============================================================================
# Image plugin for the DIB format (BMP alias)
#===============================================================================
class DibImageFile(BmpImageFile): class DibImageFile(BmpImageFile):
format = "DIB" format = "DIB"
@ -189,6 +204,8 @@ class DibImageFile(BmpImageFile):
def _open(self): def _open(self):
self._bitmap() self._bitmap()
# #
# -------------------------------------------------------------------- # --------------------------------------------------------------------
# Write BMP file # Write BMP file
@ -198,6 +215,7 @@ SAVE = {
"L": ("L", 8, 256), "L": ("L", 8, 256),
"P": ("P", 8, 256), "P": ("P", 8, 256),
"RGB": ("BGR", 24, 0), "RGB": ("BGR", 24, 0),
"RGBA": ("BGRA", 32, 0),
} }