mirror of
https://github.com/python-pillow/Pillow.git
synced 2024-11-11 04:07:21 +03:00
295 lines
13 KiB
Python
295 lines
13 KiB
Python
#
|
|
# The Python Imaging Library.
|
|
# $Id$
|
|
#
|
|
# BMP file handler
|
|
#
|
|
# Windows (and OS/2) native bitmap storage format.
|
|
#
|
|
# history:
|
|
# 1995-09-01 fl Created
|
|
# 1996-04-30 fl Added save
|
|
# 1997-08-27 fl Fixed save of 1-bit images
|
|
# 1998-03-06 fl Load P images as L where possible
|
|
# 1998-07-03 fl Load P images as 1 where possible
|
|
# 1998-12-29 fl Handle small palettes
|
|
# 2002-12-30 fl Fixed load of 1-bit palette images
|
|
# 2003-04-21 fl Fixed load of 1-bit monochrome images
|
|
# 2003-04-23 fl Added limited support for BI_BITFIELDS compression
|
|
#
|
|
# Copyright (c) 1997-2003 by Secret Labs AB
|
|
# Copyright (c) 1995-2003 by Fredrik Lundh
|
|
#
|
|
# See the README file for information on usage and redistribution.
|
|
#
|
|
|
|
|
|
from PIL import Image, ImageFile, ImagePalette, _binary
|
|
import math
|
|
|
|
__version__ = "0.7"
|
|
|
|
i8 = _binary.i8
|
|
i16 = _binary.i16le
|
|
i32 = _binary.i32le
|
|
o8 = _binary.o8
|
|
o16 = _binary.o16le
|
|
o32 = _binary.o32le
|
|
|
|
#
|
|
# --------------------------------------------------------------------
|
|
# Read BMP file
|
|
|
|
BIT2MODE = {
|
|
# bits => mode, rawmode
|
|
1: ("P", "P;1"),
|
|
4: ("P", "P;4"),
|
|
8: ("P", "P"),
|
|
16: ("RGB", "BGR;15"),
|
|
24: ("RGB", "BGR"),
|
|
32: ("RGB", "BGRX"),
|
|
}
|
|
|
|
|
|
def _accept(prefix):
|
|
return prefix[:2] == b"BM"
|
|
|
|
|
|
# ==============================================================================
|
|
# Image plugin for the Windows BMP format.
|
|
# ==============================================================================
|
|
class BmpImageFile(ImageFile.ImageFile):
|
|
""" Image plugin for the Windows Bitmap format (BMP) """
|
|
|
|
# -------------------------------------------------------------- Description
|
|
format_description = "Windows Bitmap"
|
|
format = "BMP"
|
|
# --------------------------------------------------- BMP Compression values
|
|
COMPRESSIONS = {'RAW': 0, 'RLE8': 1, 'RLE4': 2, 'BITFIELDS': 3, 'JPEG': 4, 'PNG': 5}
|
|
RAW, RLE8, RLE4, BITFIELDS, JPEG, PNG = 0, 1, 2, 3, 4, 5
|
|
|
|
def _bitmap(self, header=0, offset=0):
|
|
""" Read relevant info about the BMP """
|
|
read, seek = self.fp.read, self.fp.seek
|
|
if header:
|
|
seek(header)
|
|
file_info = dict()
|
|
file_info['header_size'] = i32(read(4)) # read bmp header size @offset 14 (this is part of the header size)
|
|
file_info['direction'] = -1
|
|
# --------------------- If requested, read header at a specific position
|
|
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'] >= 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
|
|
self.info["dpi"] = tuple(
|
|
map(lambda x: int(math.ceil(x / 39.3701)),
|
|
file_info['pixels_per_meter']))
|
|
if file_info['compression'] == self.BITFIELDS:
|
|
if len(header_data) >= 52:
|
|
for idx, mask in enumerate(['r_mask', 'g_mask', 'b_mask', 'a_mask']):
|
|
file_info[mask] = i32(header_data[36+idx*4:40+idx*4])
|
|
else:
|
|
# 40 byte headers only have the three components in the bitfields masks,
|
|
# ref: https://msdn.microsoft.com/en-us/library/windows/desktop/dd183376(v=vs.85).aspx
|
|
# See also https://github.com/python-pillow/Pillow/issues/1293
|
|
# There is a 4th component in the RGBQuad, in the alpha location, but it
|
|
# is listed as a reserved component, and it is not generally an alpha channel
|
|
file_info['a_mask'] = 0x0
|
|
for mask in ['r_mask', 'g_mask', 'b_mask']:
|
|
file_info[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'])
|
|
else:
|
|
raise IOError("Unsupported BMP header type (%d)" % file_info['header_size'])
|
|
# ------------------ Special case : header is reported 40, which
|
|
# ---------------------- is shorter than real size for bpp >= 16
|
|
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("Unsupported BMP Size: (%dx%d)" % self.size)
|
|
# ----------------------- 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("Unsupported BMP pixel depth (%d)" % 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), (0x0, 0x0, 0x0, 0x0)],
|
|
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",
|
|
(32, (0x0, 0x0, 0x0, 0x0)): "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("Unsupported BMP bitfields layout")
|
|
else:
|
|
raise IOError("Unsupported BMP bitfields layout")
|
|
elif file_info['compression'] == self.RAW:
|
|
if file_info['bits'] == 32 and header == 22: # 32-bit .cur offset
|
|
raw_mode, self.mode = "BGRA", "RGBA"
|
|
else:
|
|
raise IOError("Unsupported BMP compression (%d)" % file_info['compression'])
|
|
# ---------------- 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("Unsupported BMP Palette size (%d)" % file_info['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", 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']), offset or self.fp.tell(),
|
|
(raw_mode, ((file_info['width'] * file_info['bits'] + 31) >> 3) & (~3), file_info['direction'])
|
|
)]
|
|
|
|
def _open(self):
|
|
""" Open file, check magic number and read header """
|
|
# read 14 bytes: magic number, filesize, reserved, header final offset
|
|
head_data = self.fp.read(14)
|
|
# choke if the file does not have the required magic bytes
|
|
if head_data[0:2] != b"BM":
|
|
raise SyntaxError("Not 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)
|
|
|
|
|
|
# ==============================================================================
|
|
# Image plugin for the DIB format (BMP alias)
|
|
# ==============================================================================
|
|
class DibImageFile(BmpImageFile):
|
|
|
|
format = "DIB"
|
|
format_description = "Windows Bitmap"
|
|
|
|
def _open(self):
|
|
self._bitmap()
|
|
|
|
#
|
|
# --------------------------------------------------------------------
|
|
# Write BMP file
|
|
|
|
SAVE = {
|
|
"1": ("1", 1, 2),
|
|
"L": ("L", 8, 256),
|
|
"P": ("P", 8, 256),
|
|
"RGB": ("BGR", 24, 0),
|
|
"RGBA": ("BGRA", 32, 0),
|
|
}
|
|
|
|
|
|
def _save(im, fp, filename, check=0):
|
|
try:
|
|
rawmode, bits, colors = SAVE[im.mode]
|
|
except KeyError:
|
|
raise IOError("cannot write mode %s as BMP" % im.mode)
|
|
|
|
if check:
|
|
return check
|
|
|
|
info = im.encoderinfo
|
|
|
|
dpi = info.get("dpi", (96, 96))
|
|
|
|
# 1 meter == 39.3701 inches
|
|
ppm = tuple(map(lambda x: int(x * 39.3701), dpi))
|
|
|
|
stride = ((im.size[0]*bits+7)//8+3) & (~3)
|
|
header = 40 # or 64 for OS/2 version 2
|
|
offset = 14 + header + colors * 4
|
|
image = stride * im.size[1]
|
|
|
|
# bitmap header
|
|
fp.write(b"BM" + # file type (magic)
|
|
o32(offset+image) + # file size
|
|
o32(0) + # reserved
|
|
o32(offset)) # image data offset
|
|
|
|
# bitmap info header
|
|
fp.write(o32(header) + # info header size
|
|
o32(im.size[0]) + # width
|
|
o32(im.size[1]) + # height
|
|
o16(1) + # planes
|
|
o16(bits) + # depth
|
|
o32(0) + # compression (0=uncompressed)
|
|
o32(image) + # size of bitmap
|
|
o32(ppm[0]) + o32(ppm[1]) + # resolution
|
|
o32(colors) + # colors used
|
|
o32(colors)) # colors important
|
|
|
|
fp.write(b"\0" * (header - 40)) # padding (for OS/2 format)
|
|
|
|
if im.mode == "1":
|
|
for i in (0, 255):
|
|
fp.write(o8(i) * 4)
|
|
elif im.mode == "L":
|
|
for i in range(256):
|
|
fp.write(o8(i) * 4)
|
|
elif im.mode == "P":
|
|
fp.write(im.im.getpalette("RGB", "BGRX"))
|
|
|
|
ImageFile._save(im, fp, [("raw", (0, 0)+im.size, 0,
|
|
(rawmode, stride, -1))])
|
|
|
|
#
|
|
# --------------------------------------------------------------------
|
|
# Registry
|
|
|
|
Image.register_open(BmpImageFile.format, BmpImageFile, _accept)
|
|
Image.register_save(BmpImageFile.format, _save)
|
|
|
|
Image.register_extension(BmpImageFile.format, ".bmp")
|
|
|
|
Image.register_mime(BmpImageFile.format, "image/bmp")
|