Pillow/PIL/BmpImagePlugin.py
Brian Crowell 37f22ebfcd py3k: Use string methods instead of string module
First, we go for the obvious stuff. The string module methods are gone in
3.0, so we translate them to the appropriate methods on the string class.
2013-01-10 08:42:49 -06:00

251 lines
6.7 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.
#
__version__ = "0.7"
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", "".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")