201 lines
5 KiB
Python
201 lines
5 KiB
Python
#
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# The Python Imaging Library.
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# $Id$
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#
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# TGA file handling
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#
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# History:
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# 95-09-01 fl created (reads 24-bit files only)
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# 97-01-04 fl support more TGA versions, including compressed images
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# 98-07-04 fl fixed orientation and alpha layer bugs
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# 98-09-11 fl fixed orientation for runlength decoder
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#
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# Copyright (c) Secret Labs AB 1997-98.
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# Copyright (c) Fredrik Lundh 1995-97.
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#
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# See the README file for information on usage and redistribution.
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#
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__version__ = "0.3"
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import Image, ImageFile, ImagePalette
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#
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# --------------------------------------------------------------------
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# Read RGA file
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def i16(c):
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return ord(c[0]) + (ord(c[1])<<8)
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def i32(c):
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return ord(c[0]) + (ord(c[1])<<8) + (ord(c[2])<<16) + (ord(c[3])<<24)
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MODES = {
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# map imagetype/depth to rawmode
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(1, 8): "P",
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(3, 1): "1",
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(3, 8): "L",
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(2, 16): "BGR;5",
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(2, 24): "BGR",
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(2, 32): "BGRA",
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}
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def _accept(prefix):
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return prefix[0] == "\0"
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##
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# Image plugin for Targa files.
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class TgaImageFile(ImageFile.ImageFile):
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format = "TGA"
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format_description = "Targa"
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def _open(self):
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# process header
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s = self.fp.read(18)
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id = ord(s[0])
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colormaptype = ord(s[1])
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imagetype = ord(s[2])
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depth = ord(s[16])
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flags = ord(s[17])
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self.size = i16(s[12:]), i16(s[14:])
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# validate header fields
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if id != 0 or colormaptype not in (0, 1) or\
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self.size[0] <= 0 or self.size[1] <= 0 or\
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depth not in (1, 8, 16, 24, 32):
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raise SyntaxError, "not a TGA file"
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# image mode
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if imagetype in (3, 11):
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self.mode = "L"
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if depth == 1:
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self.mode = "1" # ???
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elif imagetype in (1, 9):
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self.mode = "P"
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elif imagetype in (2, 10):
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self.mode = "RGB"
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if depth == 32:
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self.mode = "RGBA"
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else:
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raise SyntaxError, "unknown TGA mode"
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# orientation
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orientation = flags & 0x30
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if orientation == 0x20:
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orientation = 1
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elif not orientation:
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orientation = -1
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else:
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raise SyntaxError, "unknown TGA orientation"
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self.info["orientation"] = orientation
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if imagetype & 8:
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self.info["compression"] = "tga_rle"
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if colormaptype:
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# read palette
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start, size, mapdepth = i16(s[3:]), i16(s[5:]), i16(s[7:])
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if mapdepth == 16:
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self.palette = ImagePalette.raw("BGR;16",
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"\0"*2*start + self.fp.read(2*size))
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elif mapdepth == 24:
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self.palette = ImagePalette.raw("BGR",
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"\0"*3*start + self.fp.read(3*size))
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elif mapdepth == 32:
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self.palette = ImagePalette.raw("BGRA",
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"\0"*4*start + self.fp.read(4*size))
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# setup tile descriptor
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try:
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rawmode = MODES[(imagetype&7, depth)]
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if imagetype & 8:
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# compressed
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self.tile = [("tga_rle", (0, 0)+self.size,
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self.fp.tell(), (rawmode, orientation, depth))]
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else:
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self.tile = [("raw", (0, 0)+self.size,
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self.fp.tell(), (rawmode, 0, orientation))]
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except KeyError:
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pass # cannot decode
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#
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# --------------------------------------------------------------------
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# Write TGA file
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def o16(i):
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return chr(i&255) + chr(i>>8&255)
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def o32(i):
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return chr(i&255) + chr(i>>8&255) + chr(i>>16&255) + chr(i>>24&255)
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SAVE = {
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"1": ("1", 1, 0, 3),
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"L": ("L", 8, 0, 3),
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"P": ("P", 8, 1, 1),
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"RGB": ("BGR", 24, 0, 2),
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"RGBA": ("BGRA", 32, 0, 2),
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}
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def _save(im, fp, filename, check=0):
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try:
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rawmode, bits, colormaptype, imagetype = SAVE[im.mode]
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except KeyError:
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raise IOError("cannot write mode %s as TGA" % im.mode)
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if check:
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return check
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if colormaptype:
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colormapfirst, colormaplength, colormapentry = 0, 256, 24
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else:
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colormapfirst, colormaplength, colormapentry = 0, 0, 0
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if im.mode == "RGBA":
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flags = 8
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else:
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flags = 0
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orientation = im.info.get("orientation", -1)
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if orientation > 0:
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flags = flags | 0x20
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fp.write("\000" +
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chr(colormaptype) +
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chr(imagetype) +
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o16(colormapfirst) +
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o16(colormaplength) +
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chr(colormapentry) +
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o16(0) +
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o16(0) +
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o16(im.size[0]) +
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o16(im.size[1]) +
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chr(bits) +
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chr(flags))
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if colormaptype:
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fp.write(im.im.getpalette("RGB", "BGR"))
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ImageFile._save(im, fp, [("raw", (0,0)+im.size, 0, (rawmode, 0, orientation))])
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#
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# --------------------------------------------------------------------
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# Registry
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Image.register_open("TGA", TgaImageFile, _accept)
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Image.register_save("TGA", _save)
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Image.register_extension("TGA", ".tga")
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