forked from python-pillow/Pillow
-
Notifications
You must be signed in to change notification settings - Fork 2
/
BmpImagePlugin.py
381 lines (325 loc) · 13.9 KB
/
BmpImagePlugin.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
#
# 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 . import Image, ImageFile, ImagePalette
from ._binary import i8
from ._binary import i16le as i16
from ._binary import i32le as i32
from ._binary import o8
from ._binary import o16le as o16
from ._binary import o32le as o32
#
# --------------------------------------------------------------------
# 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"
def _dib_accept(prefix):
return i32(prefix[:4]) in [12, 40, 64, 108, 124]
# =============================================================================
# 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}
for k, v in COMPRESSIONS.items():
vars()[k] = v
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 = {}
# read bmp header size @offset 14 (this is part of the header size)
file_info["header_size"] = i32(read(4))
file_info["direction"] = -1
# -------------------- If requested, read header at a specific position
# read the rest of the bmp header, without its size
header_data = ImageFile._safe_read(self.fp, file_info["header_size"] - 4)
# -------------------------------------------------- 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
# v3, OS/2 v2, v4, v5
elif file_info["header_size"] in (40, 64, 108, 124):
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])
# byte size of pixel data
file_info["data_size"] = i32(header_data[16:20])
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(
int(x / 39.3701 + 0.5) for x in 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 OSError(f"Unsupported BMP header type ({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 bit depth for unusual unsupported values
self.mode, raw_mode = BIT2MODE.get(file_info["bits"], (None, None))
if self.mode is None:
raise OSError(f"Unsupported BMP pixel depth ({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),
(0xFF, 0xFF00, 0xFF0000, 0xFF000000),
(0x0, 0x0, 0x0, 0x0),
(0xFF000000, 0xFF0000, 0xFF00, 0x0),
],
24: [(0xFF0000, 0xFF00, 0xFF)],
16: [(0xF800, 0x7E0, 0x1F), (0x7C00, 0x3E0, 0x1F)],
}
MASK_MODES = {
(32, (0xFF0000, 0xFF00, 0xFF, 0x0)): "BGRX",
(32, (0xFF000000, 0xFF0000, 0xFF00, 0x0)): "XBGR",
(32, (0xFF, 0xFF00, 0xFF0000, 0xFF000000)): "RGBA",
(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 "A" in raw_mode 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 OSError("Unsupported BMP bitfields layout")
else:
raise OSError("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 OSError(f"Unsupported BMP compression ({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 OSError(f"Unsupported BMP Palette size ({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 not _accept(head_data):
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 _dib_save(im, fp, filename):
_save(im, fp, filename, False)
def _save(im, fp, filename, bitmap_header=True):
try:
rawmode, bits, colors = SAVE[im.mode]
except KeyError as e:
raise OSError(f"cannot write mode {im.mode} as BMP") from e
info = im.encoderinfo
dpi = info.get("dpi", (96, 96))
# 1 meter == 39.3701 inches
ppm = tuple(map(lambda x: int(x * 39.3701 + 0.5), dpi))
stride = ((im.size[0] * bits + 7) // 8 + 3) & (~3)
header = 40 # or 64 for OS/2 version 2
image = stride * im.size[1]
# bitmap header
if bitmap_header:
offset = 14 + header + colors * 4
file_size = offset + image
if file_size > 2 ** 32 - 1:
raise ValueError("File size is too large for the BMP format")
fp.write(
b"BM" # file type (magic)
+ o32(file_size) # 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]) # resolution
+ 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")
Image.register_open(DibImageFile.format, DibImageFile, _dib_accept)
Image.register_save(DibImageFile.format, _dib_save)
Image.register_extension(DibImageFile.format, ".dib")
Image.register_mime(DibImageFile.format, "image/bmp")