forked from josch/img2pdf
src/img2pdf.py: add more rationale behind palette encoding
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1 changed files with 13 additions and 0 deletions
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@ -317,6 +317,10 @@ if PY3:
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string = string.encode('ascii')
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string = string.encode('ascii')
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except UnicodeEncodeError:
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except UnicodeEncodeError:
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string = b"\xfe\xff"+string.encode("utf-16-be")
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string = b"\xfe\xff"+string.encode("utf-16-be")
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# We should probably encode more here because at least
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# ghostscript interpretes a carriage return byte (0x0D) as a
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# new line byte (0x0A)
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# PDF supports: \n, \r, \t, \b and \f
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string = string.replace(b'\\', b'\\\\')
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string = string.replace(b'\\', b'\\\\')
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string = string.replace(b'(', b'\\(')
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string = string.replace(b'(', b'\\(')
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string = string.replace(b')', b'\\)')
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string = string.replace(b')', b'\\)')
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@ -780,6 +784,15 @@ def parse_png(rawdata):
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if rawdata[i-4:i] == b"IDAT":
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if rawdata[i-4:i] == b"IDAT":
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pngidat += rawdata[i:i+n]
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pngidat += rawdata[i:i+n]
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elif rawdata[i-4:i] == b"PLTE":
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elif rawdata[i-4:i] == b"PLTE":
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# This could be as simple as saying "palette = rawdata[i:i+n]" but
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# pdfrw does only escape parenthesis and backslashes in the raw
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# byte stream. But raw carriage return bytes are interpreted as
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# line feed bytes by ghostscript. So instead we use the hex string
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# format. pdfrw cannot write it but at least ghostscript is happy
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# with it. We would also write out the palette in binary format
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# (and escape more bytes) but since we cannot use pdfrw anyways,
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# we choose the more human readable variant.
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# See https://github.com/pmaupin/pdfrw/issues/147
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for j in range(i, i+n, 3):
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for j in range(i, i+n, 3):
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# with int.from_bytes() we would not have to prepend extra
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# with int.from_bytes() we would not have to prepend extra
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# zeroes
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# zeroes
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