def png_invalid_bad_palette_reference():
"""Leave out the palette on a paletted image."""
return (pngforge.sig() +
pngforge.ihdr(width=1, height=1,
color_type=pngforge.COLOR_INDEXED) +
pngforge.idat(pngforge.scanline(0, chr(0))) +
pngforge.iend())
def png_invalid_bad_palette_reference():
"""Refer to a nonexistent palette entry."""
palette = ''.join([pngforge.rgb(i,i,i) for i in range(64)])
return (pngforge.sig() +
pngforge.ihdr(width=1, height=1,
color_type=pngforge.COLOR_INDEXED) +
pngforge.chunk('PLTE', palette) +
pngforge.idat(pngforge.scanline(0, chr(64))) +
pngforge.iend())
def png_invalid_short_palette():
"""Construct a palette that isn't a multiple of 3 bytes long."""
palette = ''.join([pngforge.rgb(i,i,i) for i in range(2)])[0:5]
return (pngforge.sig() +
pngforge.ihdr(width=1, height=1,
color_type=pngforge.COLOR_INDEXED) +
pngforge.chunk('PLTE', palette) +
pngforge.idat(pngforge.scanline(0, '\0')) +
pngforge.iend())
def png_valid_tiny():
"""Create a valid, though tiny, image."""
return (pngforge.sig() + pngforge.ihdr(width=1, height=1) +
pngforge.idat(pngforge.scanline(0, '\1\2\3')) +
pngforge.iend())
def png_invalid_missing_iend():
"""A valid image, just missing the IEND."""
return (pngforge.sig() + pngforge.ihdr(width=1, height=1) +
pngforge.idat(pngforge.scanline(0, '\1\2\3')))
def png_invalid_long_idat():
"""Create a image with an overlong IDAT."""
return (pngforge.sig() + pngforge.ihdr(1, 1) +
pngforge.idat(pngforge.scanline(0, '\0' * 20)) +
pngforge.iend())
def png_invalid_short_idat():
"""Create a image with a too-short IDAT."""
return (pngforge.sig() + pngforge.ihdr(1, 1) +
pngforge.chunk('IDAT', '') +
pngforge.iend())