# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
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# modification, are permitted provided that the following conditions
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# * Redistributions of source code must retain the above copyright
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# ----------------------------------------------------------------------------
'''Decoder for BMP files.
Currently supports version 3 and 4 bitmaps with BI_RGB and BI_BITFIELDS
encoding. Alpha channel is supported for 32-bit BI_RGB only.
'''
# Official docs are at
# http://msdn2.microsoft.com/en-us/library/ms532311.aspx
#
# But some details including alignment and bit/byte order are omitted; see
# http://www.fileformat.info/format/bmp/egff.htm
__docformat__ = 'restructuredtext'
__version__ = '$Id: bmp.py 2019 2008-04-18 14:30:48Z Alex.Holkner $'
import ctypes
from pyglet.image import ImageData
from pyglet.image.codecs import ImageDecoder,ImageDecodeException
BYTE = ctypes.c_ubyte
WORD = ctypes.c_uint16
DWORD = ctypes.c_uint32
LONG = ctypes.c_int32
FXPT2DOT30 = ctypes.c_uint32
BI_RGB = 0
BI_RLE8 = 1
BI_RLE4 = 2
BI_BITFIELDS = 3
class BITMAPFILEHEADER(ctypes.LittleEndianStructure):
_pack_ = 1
_fields_ = [
('bfType', WORD),
('bfSize', DWORD),
('bfReserved1', WORD),
('bfReserved2', WORD),
('bfOffBits', DWORD)
]
class BITMAPINFOHEADER(ctypes.LittleEndianStructure):
_pack_ = 1
_fields_ = [
('biSize', DWORD),
('biWidth', LONG),
('biHeight', LONG),
('biPlanes', WORD),
('biBitCount', WORD),
('biCompression', DWORD),
('biSizeImage', DWORD),
('biXPelsPerMeter', LONG),
('biYPelsPerMeter', LONG),
('biClrUsed', DWORD),
('biClrImportant', DWORD)
]
CIEXYZTRIPLE = FXPT2DOT30 * 9
class BITMAPV4HEADER(ctypes.LittleEndianStructure):
_pack_ = 1
_fields_ = [
('biSize', DWORD),
('biWidth', LONG),
('biHeight', LONG),
('biPlanes', WORD),
('biBitCount', WORD),
('biCompression', DWORD),
('biSizeImage', DWORD),
('biXPelsPerMeter', LONG),
('biYPelsPerMeter', LONG),
('biClrUsed', DWORD),
('biClrImportant', DWORD),
('bV4RedMask', DWORD),
('bV4GreenMask', DWORD),
('bV4BlueMask', DWORD),
('bV4AlphaMask', DWORD),
('bV4CSType', DWORD),
('bV4Endpoints', CIEXYZTRIPLE),
('bV4GammaRed', DWORD),
('bV4GammaGreen', DWORD),
('bV4GammaBlue', DWORD),
]
class RGBFields(ctypes.LittleEndianStructure):
_pack_ = 1
_fields_ = [
('red', DWORD),
('green', DWORD),
('blue', DWORD),
]
class RGBQUAD(ctypes.LittleEndianStructure):
_pack_ = 1
_fields_ = [
('rgbBlue', BYTE),
('rgbGreen', BYTE),
('rgbRed', BYTE),
('rgbReserved', BYTE)
]
def __repr__(self):
return '<%d, %d, %d>' % (self.rgbRed, self.rgbGreen, self.rgbBlue)
def ptr_add(ptr, offset):
address = ctypes.addressof(ptr.contents) + offset
return ctypes.pointer(type(ptr.contents).from_address(address))
def to_ctypes(buffer, offset, type):
if offset + ctypes.sizeof(type) > len(buffer):
raise ImageDecodeException('BMP file is truncated')
ptr = ptr_add(ctypes.pointer(buffer), offset)
return ctypes.cast(ptr, ctypes.POINTER(type)).contents
class BMPImageDecoder(ImageDecoder):
def get_file_extensions(self):
return ['.bmp']
def decode(self, file, filename):
if not file:
file = open(filename, 'rb')
bytes = file.read()
buffer = ctypes.c_buffer(bytes)
if bytes[:2] != 'BM':
raise ImageDecodeException(
'Not a Windows bitmap file: %r' % (filename or file))
file_header = to_ctypes(buffer, 0, BITMAPFILEHEADER)
bits_offset = file_header.bfOffBits
info_header_offset = ctypes.sizeof(BITMAPFILEHEADER)
info_header = to_ctypes(buffer, info_header_offset, BITMAPINFOHEADER)
palette_offset = info_header_offset + info_header.biSize
if info_header.biSize < ctypes.sizeof(BITMAPINFOHEADER):
raise ImageDecodeException(
'Unsupported BMP type: %r' % (filename or file))
width = info_header.biWidth
height = info_header.biHeight
if width <= 0 or info_header.biPlanes != 1:
raise ImageDecodeException(
'BMP file has corrupt parameters: %r' % (filename or file))
pitch_sign = height < 0 and -1 or 1
height = abs(height)
compression = info_header.biCompression
if compression not in (BI_RGB, BI_BITFIELDS):
raise ImageDecodeException(
'Unsupported compression: %r' % (filename or file))
clr_used = 0
bitcount = info_header.biBitCount
if bitcount == 1:
pitch = (width + 7) // 8
bits_type = ctypes.c_ubyte
decoder = decode_1bit
elif bitcount == 4:
pitch = (width + 1) // 2
bits_type = ctypes.c_ubyte
decoder = decode_4bit
elif bitcount == 8:
bits_type = ctypes.c_ubyte
pitch = width
decoder = decode_8bit
elif bitcount == 16:
pitch = width * 2
bits_type = ctypes.c_uint16
decoder = decode_bitfields
elif bitcount == 24:
pitch = width * 3
bits_type = ctypes.c_ubyte
decoder = decode_24bit
elif bitcount == 32:
pitch = width * 4
if compression == BI_RGB:
decoder = decode_32bit_rgb
bits_type = ctypes.c_ubyte
elif compression == BI_BITFIELDS:
decoder = decode_bitfields
bits_type = ctypes.c_uint32
else:
raise ImageDecodeException(
'Unsupported compression: %r' % (filename or file))
else:
raise ImageDecodeException(
'Unsupported bit count %d: %r' % (bitcount, filename or file))
pitch = (pitch + 3) & ~3
packed_width = pitch // ctypes.sizeof(bits_type)
if bitcount < 16 and compression == BI_RGB:
clr_used = info_header.biClrUsed or (1 << bitcount)
palette = to_ctypes(buffer, palette_offset, RGBQUAD * clr_used)
bits = to_ctypes(buffer, bits_offset,
bits_type * packed_width * height)
return decoder(bits, palette, width, height, pitch, pitch_sign)
elif bitcount >= 16 and compression == BI_RGB:
bits = to_ctypes(buffer, bits_offset,
bits_type * (packed_width * height))
return decoder(bits, None, width, height, pitch, pitch_sign)
elif compression == BI_BITFIELDS:
if info_header.biSize >= ctypes.sizeof(BITMAPV4HEADER):
info_header = to_ctypes(buffer, info_header_offset,
BITMAPV4HEADER)
r_mask = info_header.bV4RedMask
g_mask = info_header.bV4GreenMask
b_mask = info_header.bV4BlueMask
else:
fields_offset = info_header_offset + \
ctypes.sizeof(BITMAPINFOHEADER)
fields = to_ctypes(buffer, fields_offset, RGBFields)
r_mask = fields.red
g_mask = fields.green
b_mask = fields.blue
class _BitsArray(ctypes.LittleEndianStructure):
_pack_ = 1
_fields_ = [
('data', bits_type * packed_width * height),
]
bits = to_ctypes(buffer, bits_offset, _BitsArray).data
return decoder(bits, r_mask, g_mask, b_mask,
width, height, pitch, pitch_sign)
def decode_1bit(bits, palette, width, height, pitch, pitch_sign):
rgb_pitch = (((pitch << 3) + 7) & ~0x7) * 3
buffer = (ctypes.c_ubyte * (height * rgb_pitch))()
i = 0
for row in bits:
for packed in row:
for _ in range(8):
rgb = palette[(packed & 0x80) >> 7]
buffer[i] = rgb.rgbRed
buffer[i + 1] = rgb.rgbGreen
buffer[i + 2] = rgb.rgbBlue
i += 3
packed <<= 1
return ImageData(width, height, 'RGB', buffer, pitch_sign * rgb_pitch)
def decode_4bit(bits, palette, width, height, pitch, pitch_sign):
rgb_pitch = (((pitch << 1) + 1) & ~0x1) * 3
buffer = (ctypes.c_ubyte * (height * rgb_pitch))()
i = 0
for row in bits:
for packed in row:
for index in ((packed & 0xf0) >> 4, packed & 0xf):
rgb = palette[index]
buffer[i] = rgb.rgbRed
buffer[i + 1] = rgb.rgbGreen
buffer[i + 2] = rgb.rgbBlue
i += 3
return ImageData(width, height, 'RGB', buffer, pitch_sign * rgb_pitch)
def decode_8bit(bits, palette, width, height, pitch, pitch_sign):
rgb_pitch = pitch * 3
buffer = (ctypes.c_ubyte * (height * rgb_pitch))()
i = 0
for row in bits:
for index in row:
rgb = palette[index]
buffer[i] = rgb.rgbRed
buffer[i + 1] = rgb.rgbGreen
buffer[i + 2] = rgb.rgbBlue
i += 3
return ImageData(width, height, 'RGB', buffer, pitch_sign * rgb_pitch)
def decode_24bit(bits, palette, width, height, pitch, pitch_sign):
buffer = (ctypes.c_ubyte * (height * pitch))()
ctypes.memmove(buffer, bits, len(buffer))
return ImageData(width, height, 'BGR', buffer, pitch_sign * pitch)
def decode_32bit_rgb(bits, palette, width, height, pitch, pitch_sign):
buffer = (ctypes.c_ubyte * (height * pitch))()
ctypes.memmove(buffer, bits, len(buffer))
return ImageData(width, height, 'BGRA', buffer, pitch_sign * pitch)
def get_shift(mask):
if not mask:
return 0
# Shift down
shift = 0
while not (1 << shift) & mask:
shift += 1
# Shift up
shift_up = 0
while (mask >> shift) >> shift_up:
shift_up += 1
s = shift - (8 - shift_up)
if s < 0:
return 0, -s
else:
return s, 0
def decode_bitfields(bits, r_mask, g_mask, b_mask,
width, height, pitch, pitch_sign):
r_shift1, r_shift2 = get_shift(r_mask)
g_shift1, g_shift2 = get_shift(g_mask)
b_shift1, b_shift2 = get_shift(b_mask)
rgb_pitch = 3 * len(bits[0])
buffer = (ctypes.c_ubyte * (height * rgb_pitch))()
i = 0
for row in bits:
for packed in row:
buffer[i] = (packed & r_mask) >> r_shift1 << r_shift2
buffer[i+1] = (packed & g_mask) >> g_shift1 << g_shift2
buffer[i+2] = (packed & b_mask) >> b_shift1 << b_shift2
i += 3
return ImageData(width, height, 'RGB', buffer, pitch_sign * rgb_pitch)
def get_decoders():
return [BMPImageDecoder()]
def get_encoders():
return []
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