Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/PIL/SgiImagePlugin.py: 56%

1# 

2# The Python Imaging Library. 

3# $Id$ 

4# 

5# SGI image file handling 

6# 

7# See "The SGI Image File Format (Draft version 0.97)", Paul Haeberli. 

8# <ftp://ftp.sgi.com/graphics/SGIIMAGESPEC> 

9# 

10# 

11# History: 

12# 2017-22-07 mb Add RLE decompression 

13# 2016-16-10 mb Add save method without compression 

14# 1995-09-10 fl Created 

15# 

16# Copyright (c) 2016 by Mickael Bonfill. 

17# Copyright (c) 2008 by Karsten Hiddemann. 

18# Copyright (c) 1997 by Secret Labs AB. 

19# Copyright (c) 1995 by Fredrik Lundh. 

20# 

21# See the README file for information on usage and redistribution. 

22# 

23from __future__ import annotations 

24 

25import os 

26import struct 

27from typing import IO 

28 

29from . import Image, ImageFile 

30from ._binary import i16be as i16 

31from ._binary import o8 

32 

33 

34def _accept(prefix: bytes) -> bool: 

35 return len(prefix) >= 2 and i16(prefix) == 474 

36 

37 

38MODES = { 

39 (1, 1, 1): "L", 

40 (1, 2, 1): "L", 

41 (2, 1, 1): "L;16B", 

42 (2, 2, 1): "L;16B", 

43 (1, 3, 3): "RGB", 

44 (2, 3, 3): "RGB;16B", 

45 (1, 3, 4): "RGBA", 

46 (2, 3, 4): "RGBA;16B", 

47} 

48 

49 

50## 

51# Image plugin for SGI images. 

52class SgiImageFile(ImageFile.ImageFile): 

53 format = "SGI" 

54 format_description = "SGI Image File Format" 

55 

56 def _open(self) -> None: 

57 # HEAD 

58 assert self.fp is not None 

59 

60 headlen = 512 

61 s = self.fp.read(headlen) 

62 

63 if not _accept(s): 

64 msg = "Not an SGI image file" 

65 raise ValueError(msg) 

66 

67 # compression : verbatim or RLE 

68 compression = s[2] 

69 

70 # bpc : 1 or 2 bytes (8bits or 16bits) 

71 bpc = s[3] 

72 

73 # dimension : 1, 2 or 3 (depending on xsize, ysize and zsize) 

74 dimension = i16(s, 4) 

75 

76 # xsize : width 

77 xsize = i16(s, 6) 

78 

79 # ysize : height 

80 ysize = i16(s, 8) 

81 

82 # zsize : channels count 

83 zsize = i16(s, 10) 

84 

85 # determine mode from bits/zsize 

86 try: 

87 rawmode = MODES[(bpc, dimension, zsize)] 

88 except KeyError: 

89 msg = "Unsupported SGI image mode" 

90 raise ValueError(msg) 

91 

92 self._size = xsize, ysize 

93 self._mode = rawmode.split(";")[0] 

94 if self.mode == "RGB": 

95 self.custom_mimetype = "image/rgb" 

96 

97 # orientation -1 : scanlines begins at the bottom-left corner 

98 orientation = -1 

99 

100 # decoder info 

101 if compression == 0: 

102 pagesize = xsize * ysize * bpc 

103 if bpc == 2: 

104 self.tile = [ 

105 ImageFile._Tile( 

106 "SGI16", 

107 (0, 0) + self.size, 

108 headlen, 

109 (self.mode, 0, orientation), 

110 ) 

111 ] 

112 else: 

113 self.tile = [] 

114 offset = headlen 

115 for layer in self.mode: 

116 self.tile.append( 

117 ImageFile._Tile( 

118 "raw", (0, 0) + self.size, offset, (layer, 0, orientation) 

119 ) 

120 ) 

121 offset += pagesize 

122 elif compression == 1: 

123 self.tile = [ 

124 ImageFile._Tile( 

125 "sgi_rle", (0, 0) + self.size, headlen, (rawmode, orientation, bpc) 

126 ) 

127 ] 

128 

129 

130def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None: 

131 if im.mode not in {"RGB", "RGBA", "L"}: 

132 msg = "Unsupported SGI image mode" 

133 raise ValueError(msg) 

134 

135 # Get the keyword arguments 

136 info = im.encoderinfo 

137 

138 # Byte-per-pixel precision, 1 = 8bits per pixel 

139 bpc = info.get("bpc", 1) 

140 

141 if bpc not in (1, 2): 

142 msg = "Unsupported number of bytes per pixel" 

143 raise ValueError(msg) 

144 

145 # Flip the image, since the origin of SGI file is the bottom-left corner 

146 orientation = -1 

147 # Define the file as SGI File Format 

148 magic_number = 474 

149 # Run-Length Encoding Compression - Unsupported at this time 

150 rle = 0 

151 

152 # X Dimension = width / Y Dimension = height 

153 x, y = im.size 

154 # Z Dimension: Number of channels 

155 z = len(im.mode) 

156 # Number of dimensions (x,y,z) 

157 if im.mode == "L": 

158 dimension = 1 if y == 1 else 2 

159 else: 

160 dimension = 3 

161 

162 # Minimum Byte value 

163 pinmin = 0 

164 # Maximum Byte value (255 = 8bits per pixel) 

165 pinmax = 255 

166 # Image name (79 characters max, truncated below in write) 

167 img_name = os.path.splitext(os.path.basename(filename))[0] 

168 if isinstance(img_name, str): 

169 img_name = img_name.encode("ascii", "ignore") 

170 # Standard representation of pixel in the file 

171 colormap = 0 

172 fp.write(struct.pack(">h", magic_number)) 

173 fp.write(o8(rle)) 

174 fp.write(o8(bpc)) 

175 fp.write(struct.pack(">H", dimension)) 

176 fp.write(struct.pack(">H", x)) 

177 fp.write(struct.pack(">H", y)) 

178 fp.write(struct.pack(">H", z)) 

179 fp.write(struct.pack(">l", pinmin)) 

180 fp.write(struct.pack(">l", pinmax)) 

181 fp.write(struct.pack("4s", b"")) # dummy 

182 fp.write(struct.pack("79s", img_name)) # truncates to 79 chars 

183 fp.write(struct.pack("s", b"")) # force null byte after img_name 

184 fp.write(struct.pack(">l", colormap)) 

185 fp.write(struct.pack("404s", b"")) # dummy 

186 

187 rawmode = "L" 

188 if bpc == 2: 

189 rawmode = "L;16B" 

190 

191 for channel in im.split(): 

192 fp.write(channel.tobytes("raw", rawmode, 0, orientation)) 

193 

194 if hasattr(fp, "flush"): 

195 fp.flush() 

196 

197 

198class SGI16Decoder(ImageFile.PyDecoder): 

199 _pulls_fd = True 

200 

201 def decode(self, buffer: bytes | Image.SupportsArrayInterface) -> tuple[int, int]: 

202 assert self.fd is not None 

203 assert self.im is not None 

204 

205 rawmode, stride, orientation = self.args 

206 pagesize = self.state.xsize * self.state.ysize 

207 zsize = len(self.mode) 

208 self.fd.seek(512) 

209 

210 for band in range(zsize): 

211 channel = Image.new("L", (self.state.xsize, self.state.ysize)) 

212 channel.frombytes( 

213 self.fd.read(2 * pagesize), "raw", "L;16B", stride, orientation 

214 ) 

215 self.im.putband(channel.im, band) 

216 

217 return -1, 0 

218 

219 

220# 

221# registry 

222 

223 

224Image.register_decoder("SGI16", SGI16Decoder) 

225Image.register_open(SgiImageFile.format, SgiImageFile, _accept) 

226Image.register_save(SgiImageFile.format, _save) 

227Image.register_mime(SgiImageFile.format, "image/sgi") 

228 

229Image.register_extensions(SgiImageFile.format, [".bw", ".rgb", ".rgba", ".sgi"]) 

230 

231# End of file