magic_bytes="P7"

header_token_endhdr="ENDHDR"
header_token_width="WIDTH"
header_token_height="HEIGHT"
header_token_depth="DEPTH"
header_token_maxval="MAXVAL"
header_token_tupltype="TUPLTYPE"

tupltype_value_blackandwhite="BLACKANDWHITE"
tupltype_value_grayscale="GRAYSCALE"
tupltype_value_rgb="RGB"
tupltype_value_cmyk="CMYK"
tupltype_value_alpha_suffix="_ALPHA"