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Diffstat (limited to 'lib/Python/Lib/PIL/BmpImagePlugin.py')
| -rw-r--r-- | lib/Python/Lib/PIL/BmpImagePlugin.py | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/lib/Python/Lib/PIL/BmpImagePlugin.py b/lib/Python/Lib/PIL/BmpImagePlugin.py new file mode 100644 index 000000000..30ca10971 --- /dev/null +++ b/lib/Python/Lib/PIL/BmpImagePlugin.py @@ -0,0 +1,281 @@ +# +# 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" + + +from PIL import Image, ImageFile, ImagePalette, _binary +import math + + +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: 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: + for mask in ['r_mask', 'g_mask', 'b_mask', 'a_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") |