pyffi.formats.tga

96 """This class implements the TGA format.""" 97 xml_file_name = 'tga.xml' 98 # where to look for tga.xml and in what order: 99 # TGAXMLPATH env var, or TgaFormat module directory 100 xml_file_path = [os.getenv('TGAXMLPATH'), os.path.dirname(__file__)] 101 # filter for recognizing tga files by extension 102 RE_FILENAME = re.compile(r'^.*\.tga$', re.IGNORECASE) 103 104 # basic types 105 int = pyffi.object_models.common.Int 106 uint = pyffi.object_models.common.UInt 107 byte = pyffi.object_models.common.Byte 108 ubyte = pyffi.object_models.common.UByte 109 char = pyffi.object_models.common.Char 110 short = pyffi.object_models.common.Short 111 ushort = pyffi.object_models.common.UShort 112 float = pyffi.object_models.common.Float 113 PixelData = pyffi.object_models.common.UndecodedData 114

115 - class FooterString(pyffi.object_models.xml.basic.BasicBase):

116 """The Targa footer signature."""

117 - def __str__(self):

118 return 'TRUEVISION-XFILE.\x00'

119

120 - def read(self, stream, data):

121 """Read signature from stream. 122 123 :param stream: The stream to read from. 124 :type stream: file 125 """ 126 signat = stream.read(18) 127 if signat != self.__str__().encode("ascii"): 128 raise ValueError( 129 "invalid Targa signature: expected '%s' but got '%s'" 130 %(self.__str__(), signat))

131

132 - def write(self, stream, data):

133 """Write signature to stream. 134 135 :param stream: The stream to read from. 136 :type stream: file 137 """ 138 stream.write(self.__str__().encode("ascii"))

139

140 - def get_value(self):

141 """Get signature. 142 143 :return: The signature. 144 """ 145 return self.__str__()

146

147 - def set_value(self, value):

148 """Set signature. 149 150 :param value: The value to assign. 151 :type value: str 152 """ 153 if value != self.__str__(): 154 raise ValueError( 155 "invalid Targa signature: expected '%s' but got '%s'" 156 %(self.__str__(), value))

157

158 - def get_size(self, data=None):

159 """Return number of bytes that the signature occupies in a file. 160 161 :return: Number of bytes. 162 """ 163 return 18

164

165 - def get_hash(self, data=None):

166 """Return a hash value for the signature. 167 168 :return: An immutable object that can be used as a hash. 169 """ 170 return self.__str__()

171

172 - class Image(pyffi.utils.graph.GlobalNode):

173 - def __init__(self):

174 # children are either individual pixels, or RLE packets 175 self.children = []

176

177 - def read(self, stream, data):

178 data = data 179 if data.header.image_type in (TgaFormat.ImageType.INDEXED, 180 TgaFormat.ImageType.RGB, 181 TgaFormat.ImageType.GREY): 182 self.children = [ 183 TgaFormat.Pixel(argument=data.header.pixel_size) 184 for i in xrange(data.header.width 185 * data.header.height)] 186 for pixel in self.children: 187 pixel.read(stream, data) 188 else: 189 self.children = [] 190 count = 0 191 while count < data.header.width * data.header.height: 192 pixel = TgaFormat.RLEPixels( 193 argument=data.header.pixel_size) 194 pixel.read(stream, data) 195 self.children.append(pixel) 196 count += pixel.header.count + 1

197

198 - def write(self, stream, data):

199 data = data 200 for child in self.children: 201 child.arg = data.header.pixel_size 202 child.write(stream, data)

203

204 - def get_detail_child_nodes(self, edge_filter=EdgeFilter()):

205 for child in self.children: 206 yield child

207

208 - def get_detail_child_names(self, edge_filter=EdgeFilter()):

209 for i in xrange(len(self.children)): 210 yield str(i)

211

212 - class Data(pyffi.object_models.FileFormat.Data):

213

214 - def __init__(self):

215 self.header = TgaFormat.Header() 216 self.image = TgaFormat.Image() 217 self.footer = None # TgaFormat.Footer() is optional

218

219 - def inspect(self, stream):

220 """Quick heuristic check if stream contains Targa data, 221 by looking at the first 18 bytes. 222 223 :param stream: The stream to inspect. 224 :type stream: file 225 """ 226 # XXX todo: set some of the actual fields of the header 227 228 pos = stream.tell() 229 # read header 230 try: 231 id_length, colormap_type, image_type, \ 232 colormap_index, colormap_length, colormap_size, \ 233 x_origin, y_origin, width, height, \ 234 pixel_size, flags = struct.unpack("<BBBHHBHHHHBB", 235 stream.read(18)) 236 except struct.error: 237 # could not read 18 bytes 238 # not a TGA file 239 raise ValueError("Not a Targa file.") 240 finally: 241 stream.seek(pos) 242 # check if tga type is valid 243 # check pixel size 244 # check width and height 245 if not(image_type in (1, 2, 3, 9, 10, 11) 246 and pixel_size in (8, 24, 32) 247 and width <= 100000 248 and height <= 100000): 249 raise ValueError("Not a Targa file.")

250 # this looks like a tga file! 251

252 - def read(self, stream):

253 """Read a tga file. 254 255 :param stream: The stream from which to read. 256 :type stream: ``file`` 257 """ 258 # read the file 259 self.inspect(stream) # quick check 260 261 # header 262 self.header.read(stream, self) 263 264 # image 265 self.image.read(stream, self) 266 267 # check if we are at the end of the file 268 if not stream.read(1): 269 self.footer = None 270 return 271 272 # footer 273 stream.seek(-26, os.SEEK_END) 274 self.footer = TgaFormat.Footer() 275 self.footer.read(stream, self)

276

277 - def write(self, stream):

278 """Write a tga file. 279 280 :param stream: The stream to write to. 281 :type stream: ``file`` 282 """ 283 self.header.write(stream, self) 284 self.image.write(stream, self) 285 if self.footer: 286 self.footer.write(stream, self)

287

288 - def get_global_child_nodes(self, edge_filter=EdgeFilter()):

289 yield self.header 290 yield self.image 291 if self.footer: 292 yield self.footer

293

294 - def get_global_child_names(self, edge_filter=EdgeFilter()):

295 yield "Header" 296 yield "Image" 297 if self.footer: 298 yield "Footer"

Source Code for Package pyffi.formats.tga