An 8-bit PCX file whose image data is followed by the palette marker
(0x0C) and fewer than 768 color bytes was read as gray levels. The reader
now notes where the run-length encoded image data ends, and when the
palette marker follows it without all 768 colors, refuses the file as cut
short. An 8-bit file with nothing after its image data still reads as
gray levels, and a gray level of 12 that falls 769 bytes before the end of
such a file is read as a pixel instead of as the palette marker.
A new reader, written from the ZSoft PCX Technical Reference Manual, decodes
the run-length encoded scan lines of 1-bit images in the header palette's
first two colors (black and white when the version has no palette or the two
colors are the same), 1-bit images in two to four planes and 4-bit images
with the header's palette (the EGA colors for versions 0 and 3), 2-bit CGA
images in the colors that the header's CGA background and palette settings
pick, 8-bit images with the 256-color palette after the image data (gray
levels without one) and 24-bit images in three planes. The image is stored as PNG at the resolution of the header's HDpi and
VDpi fields.
Open and Place list PCX, and pasting a copied .pcx file and Glass's Load
Texture… read it by its header. A file of another depth or plane count, one
cut short and one whose pixels as RGBA pass the pixel allowance are refused
with a message before its pixels are decoded. The desktop packaging does not
associate .pcx files, and no export writes them.
Docs: docs/file-format-parity.md, docs/target-app-parity.md, docs/mcp.md,
docs/releasing.md.
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