PNG: Decoding

WARNING

• PNG is pre-v1.0.0, and the public API should be expected to change between releases.
  Not all features defined in the PNG 3.0 specification are currently supported, and certain PNG data may fail or partially fail to decode. (for more information, see PNG: Decoding, Compatibility)

Options

decode() accepts an optional png.DecodeOptions table to configure decoding behavior:

• crc: String literal specifying which chunk checksums are validated.
  • "all" (default): All chunks are validated.
  • "critical": Only critical chunks are validated.
  • "none": Checksum validation is skipped entirely.

Static Image Example

Below, we decode the static image (or the first frame) from a source PNG.
CRCs are skipped, and parameters for cel() are left at defaults (frame 0, RGBA8 output)

local parsed, err = png.decode(source, {
	crc = "none"
})
if parsed == nil then
	error(`error ({err.code}): {err.message}`)
end

local cel, err = parsed.cel()
if cel == nil then
	error(`error ({err.code}): {err.message}`)
end

Compatibility

• 16-bit depth: Supported. Use a 16-bit color target in cel() to preserve full color depth.
• Metadata: Ancillary chunks are parsed, but not yet exposed via a public API (planned)
• Animation (APNG): Unsupported (planned)
• Interlacing (Adam7): Unsupported (planned)