Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/PIL/ImagePalette.py: 53%

1# 

2# The Python Imaging Library. 

3# $Id$ 

4# 

5# image palette object 

6# 

7# History: 

8# 1996-03-11 fl Rewritten. 

9# 1997-01-03 fl Up and running. 

10# 1997-08-23 fl Added load hack 

11# 2001-04-16 fl Fixed randint shadow bug in random() 

12# 

13# Copyright (c) 1997-2001 by Secret Labs AB 

14# Copyright (c) 1996-1997 by Fredrik Lundh 

15# 

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

17# 

18from __future__ import annotations 

19 

20import array 

21from collections.abc import Sequence 

22from typing import IO 

23 

24from . import GimpGradientFile, GimpPaletteFile, ImageColor, PaletteFile 

25 

26TYPE_CHECKING = False 

27if TYPE_CHECKING: 

28 from . import Image 

29 

30 

31class ImagePalette: 

32 """ 

33 Color palette for palette mapped images 

34 

35 :param mode: The mode to use for the palette. See: 

36 :ref:`concept-modes`. Defaults to "RGB" 

37 :param palette: An optional palette. If given, it must be a bytearray, 

38 an array or a list of ints between 0-255. The list must consist of 

39 all channels for one color followed by the next color (e.g. RGBRGBRGB). 

40 Defaults to an empty palette. 

41 """ 

42 

43 def __init__( 

44 self, 

45 mode: str = "RGB", 

46 palette: Sequence[int] | bytes | bytearray | None = None, 

47 ) -> None: 

48 self.mode = mode 

49 self.rawmode: str | None = None # if set, palette contains raw data 

50 self.palette = palette or bytearray() 

51 self.dirty: int | None = None 

52 

53 @property 

54 def palette(self) -> Sequence[int] | bytes | bytearray: 

55 return self._palette 

56 

57 @palette.setter 

58 def palette(self, palette: Sequence[int] | bytes | bytearray) -> None: 

59 self._colors: dict[tuple[int, ...], int] | None = None 

60 self._palette = palette 

61 

62 @property 

63 def colors(self) -> dict[tuple[int, ...], int]: 

64 if self._colors is None: 

65 mode_len = len(self.mode) 

66 self._colors = {} 

67 for i in range(0, len(self.palette), mode_len): 

68 color = tuple(self.palette[i : i + mode_len]) 

69 if color in self._colors: 

70 continue 

71 self._colors[color] = i // mode_len 

72 return self._colors 

73 

74 @colors.setter 

75 def colors(self, colors: dict[tuple[int, ...], int]) -> None: 

76 self._colors = colors 

77 

78 def copy(self) -> ImagePalette: 

79 new = ImagePalette() 

80 

81 new.mode = self.mode 

82 new.rawmode = self.rawmode 

83 if self.palette is not None: 

84 new.palette = self.palette[:] 

85 new.dirty = self.dirty 

86 

87 return new 

88 

89 def getdata(self) -> tuple[str, Sequence[int] | bytes | bytearray]: 

90 """ 

91 Get palette contents in format suitable for the low-level 

92 ``im.putpalette`` primitive. 

93 

94 .. warning:: This method is experimental. 

95 """ 

96 if self.rawmode: 

97 return self.rawmode, self.palette 

98 return self.mode, self.tobytes() 

99 

100 def tobytes(self) -> bytes: 

101 """Convert palette to bytes. 

102 

103 .. warning:: This method is experimental. 

104 """ 

105 if self.rawmode: 

106 msg = "palette contains raw palette data" 

107 raise ValueError(msg) 

108 if isinstance(self.palette, bytes): 

109 return self.palette 

110 arr = array.array("B", self.palette) 

111 return arr.tobytes() 

112 

113 # Declare tostring as an alias for tobytes 

114 tostring = tobytes 

115 

116 def _new_color_index( 

117 self, image: Image.Image | None = None, e: Exception | None = None 

118 ) -> int: 

119 if not isinstance(self.palette, bytearray): 

120 self._palette = bytearray(self.palette) 

121 index = len(self.palette) // 3 

122 special_colors: tuple[int | tuple[int, ...] | None, ...] = () 

123 if image: 

124 special_colors = ( 

125 image.info.get("background"), 

126 image.info.get("transparency"), 

127 ) 

128 while index in special_colors: 

129 index += 1 

130 if index >= 256: 

131 if image: 

132 # Search for an unused index 

133 for i, count in reversed(list(enumerate(image.histogram()))): 

134 if count == 0 and i not in special_colors: 

135 index = i 

136 break 

137 if index >= 256: 

138 msg = "cannot allocate more than 256 colors" 

139 raise ValueError(msg) from e 

140 return index 

141 

142 def getcolor( 

143 self, 

144 color: tuple[int, ...], 

145 image: Image.Image | None = None, 

146 ) -> int: 

147 """Given an rgb tuple, allocate palette entry. 

148 

149 .. warning:: This method is experimental. 

150 """ 

151 if self.rawmode: 

152 msg = "palette contains raw palette data" 

153 raise ValueError(msg) 

154 if isinstance(color, tuple): 

155 if self.mode == "RGB": 

156 if len(color) == 4: 

157 if color[3] != 255: 

158 msg = "cannot add non-opaque RGBA color to RGB palette" 

159 raise ValueError(msg) 

160 color = color[:3] 

161 elif self.mode == "RGBA": 

162 if len(color) == 3: 

163 color += (255,) 

164 try: 

165 return self.colors[color] 

166 except KeyError as e: 

167 # allocate new color slot 

168 index = self._new_color_index(image, e) 

169 assert isinstance(self._palette, bytearray) 

170 self.colors[color] = index 

171 if index * 3 < len(self.palette): 

172 self._palette = ( 

173 self._palette[: index * 3] 

174 + bytes(color) 

175 + self._palette[index * 3 + 3 :] 

176 ) 

177 else: 

178 self._palette += bytes(color) 

179 self.dirty = 1 

180 return index 

181 else: 

182 msg = f"unknown color specifier: {repr(color)}" # type: ignore[unreachable] 

183 raise ValueError(msg) 

184 

185 def save(self, fp: str | IO[str]) -> None: 

186 """Save palette to text file. 

187 

188 .. warning:: This method is experimental. 

189 """ 

190 if self.rawmode: 

191 msg = "palette contains raw palette data" 

192 raise ValueError(msg) 

193 if isinstance(fp, str): 

194 fp = open(fp, "w") 

195 fp.write("# Palette\n") 

196 fp.write(f"# Mode: {self.mode}\n") 

197 for i in range(256): 

198 fp.write(f"{i}") 

199 for j in range(i * len(self.mode), (i + 1) * len(self.mode)): 

200 try: 

201 fp.write(f" {self.palette[j]}") 

202 except IndexError: 

203 fp.write(" 0") 

204 fp.write("\n") 

205 fp.close() 

206 

207 

208# -------------------------------------------------------------------- 

209# Internal 

210 

211 

212def raw(rawmode: str, data: Sequence[int] | bytes | bytearray) -> ImagePalette: 

213 palette = ImagePalette() 

214 palette.rawmode = rawmode 

215 palette.palette = data 

216 palette.dirty = 1 

217 return palette 

218 

219 

220# -------------------------------------------------------------------- 

221# Factories 

222 

223 

224def make_linear_lut(black: int, white: float) -> list[int]: 

225 if black == 0: 

226 return [int(white * i // 255) for i in range(256)] 

227 

228 msg = "unavailable when black is non-zero" 

229 raise NotImplementedError(msg) # FIXME 

230 

231 

232def make_gamma_lut(exp: float) -> list[int]: 

233 return [int(((i / 255.0) ** exp) * 255.0 + 0.5) for i in range(256)] 

234 

235 

236def negative(mode: str = "RGB") -> ImagePalette: 

237 palette = list(range(256 * len(mode))) 

238 palette.reverse() 

239 return ImagePalette(mode, [i // len(mode) for i in palette]) 

240 

241 

242def random(mode: str = "RGB") -> ImagePalette: 

243 from random import randint 

244 

245 palette = [randint(0, 255) for _ in range(256 * len(mode))] 

246 return ImagePalette(mode, palette) 

247 

248 

249def sepia(white: str = "#fff0c0") -> ImagePalette: 

250 bands = [make_linear_lut(0, band) for band in ImageColor.getrgb(white)] 

251 return ImagePalette("RGB", [bands[i % 3][i // 3] for i in range(256 * 3)]) 

252 

253 

254def wedge(mode: str = "RGB") -> ImagePalette: 

255 palette = list(range(256 * len(mode))) 

256 return ImagePalette(mode, [i // len(mode) for i in palette]) 

257 

258 

259def load(filename: str) -> tuple[bytes, str]: 

260 # FIXME: supports GIMP gradients only 

261 

262 with open(filename, "rb") as fp: 

263 paletteHandlers: list[ 

264 type[ 

265 GimpPaletteFile.GimpPaletteFile 

266 | GimpGradientFile.GimpGradientFile 

267 | PaletteFile.PaletteFile 

268 ] 

269 ] = [ 

270 GimpPaletteFile.GimpPaletteFile, 

271 GimpGradientFile.GimpGradientFile, 

272 PaletteFile.PaletteFile, 

273 ] 

274 for paletteHandler in paletteHandlers: 

275 try: 

276 fp.seek(0) 

277 lut = paletteHandler(fp).getpalette() 

278 if lut: 

279 break 

280 except (SyntaxError, ValueError): 

281 pass 

282 else: 

283 msg = "cannot load palette" 

284 raise OSError(msg) 

285 

286 return lut # data, rawmode