#
# 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.
#
__version__ = "0.7"
import string
import Image, ImageFile, ImagePalette
#
# --------------------------------------------------------------------
# Read BMP file
def i16(c):
return ord(c[0]) + (ord(c[1])<<8)
def i32(c):
return ord(c[0]) + (ord(c[1])<<8) + (ord(c[2])<<16) + (ord(c[3])<<24)
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] == "BM"
##
# Image plugin for the Windows BMP format.
class BmpImageFile(ImageFile.ImageFile):
format = "BMP"
format_description = "Windows Bitmap"
def _bitmap(self, header = 0, offset = 0):
if header:
self.fp.seek(header)
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]:
# 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:])
lutsize = 4
colors = i32(s[32:])
direction = -1
if s[11] == '\xff':
# upside-down storage
self.size = self.size[0], 2**32 - self.size[1]
direction = 0
else:
raise IOError("Unsupported BMP header type (%d)" % len(s))
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)
else:
indices = range(colors)
for i in indices:
rgb = read(lutsize)[:3]
if rgb != chr(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", string.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):
# HEAD
s = self.fp.read(14)
if s[:2] != "BM":
raise SyntaxError("Not a BMP file")
offset = i32(s[10:])
self._bitmap(offset=offset)
class DibImageFile(BmpImageFile):
format = "DIB"
format_description = "Windows Bitmap"
def _open(self):
self._bitmap()
#
# --------------------------------------------------------------------
# Write BMP file
def o16(i):
return chr(i&255) + chr(i>>8&255)
def o32(i):
return chr(i&255) + chr(i>>8&255) + chr(i>>16&255) + chr(i>>24&255)
SAVE = {
"1": ("1", 1, 2),
"L": ("L", 8, 256),
"P": ("P", 8, 256),
"RGB": ("BGR", 24, 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
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("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(1) + o32(1) + # resolution
o32(colors) + # colors used
o32(colors)) # colors important
fp.write("\000" * (header - 40)) # padding (for OS/2 format)
if im.mode == "1":
for i in (0, 255):
fp.write(chr(i) * 4)
elif im.mode == "L":
for i in range(256):
fp.write(chr(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")
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