From 5f7908f8a47341a3b51aaee46755b221b681837e Mon Sep 17 00:00:00 2001 From: Ryan Oldenburg Date: Sat, 21 Nov 2020 01:08:56 -0600 Subject: [PATCH] transparency chunk --- src/pixie/fileformats/png.nim | 57 +++++++++++++++---- tests/pngsuite.nim | 103 ++++++++++++++++++++++++++++++++++ 2 files changed, 149 insertions(+), 11 deletions(-) diff --git a/src/pixie/fileformats/png.nim b/src/pixie/fileformats/png.nim index d0c3827..ef5d970 100644 --- a/src/pixie/fileformats/png.nim +++ b/src/pixie/fileformats/png.nim @@ -7,7 +7,7 @@ const type ChunkCounts = object - PLTE, IDAT: uint8 + PLTE, IDAT, tRNS: uint8 PngHeader = object width, height: int @@ -146,7 +146,9 @@ proc unfilter( result[unfiteredIdx(x, y)] = value proc parseImageData( - header: PngHeader, palette: seq[array[3, uint8]], data: seq[uint8] + header: PngHeader, + palette: seq[array[3, uint8]], + transparency, data: seq[uint8] ): seq[ColorRGBA] = result.setLen(header.width * header.height) @@ -178,6 +180,7 @@ proc parseImageData( case header.colorType: of 0: + let special = if transparency.len == 2: transparency[1].int else: -1 var bytePos, bitPos: int for y in 0 ..< header.height: for x in 0 ..< header.width: @@ -204,8 +207,9 @@ proc parseImageData( inc bytePos bitPos = 0 + let alpha = if value.int == special: 0 else: 255 result[x + y * header.width] = ColorRGBA( - r: value, g: value, b: value, a: 255 + r: value, g: value, b: value, a: alpha.uint8 ) # If we move to a new row, skip to the next full byte @@ -213,13 +217,21 @@ proc parseImageData( inc bytePos bitPos = 0 of 2: + let special = + if transparency.len == 6: + ColorRGBA( + r: transparency[1], g: transparency[3], b: transparency[5], a: 255 + ) + else: + ColorRGBA() var bytePos: int for y in 0 ..< header.height: for x in 0 ..< header.width: let rgb = cast[ptr array[3, uint8]](unfiltered[bytePos].unsafeAddr)[] - result[x + y * header.width] = ColorRGBA( - r: rgb[0], g: rgb[1], b: rgb[2], a: 255 - ) + var rgba = ColorRGBA(r: rgb[0], g: rgb[1], b: rgb[2], a: 255) + if rgba == special: + rgba.a = 0 + result[x + y * header.width] = rgba bytePos += 3 of 3: var bytePos, bitPos: int @@ -247,9 +259,15 @@ proc parseImageData( if value.int >= palette.len: failInvalid() - let rgb = palette[value] + let + rgb = palette[value] + transparency = + if transparency.len > value.int: + transparency[value] + else: + 255 result[x + y * header.width] = ColorRGBA( - r: rgb[0], g: rgb[1], b: rgb[2], a: 255 + r: rgb[0], g: rgb[1], b: rgb[2], a: transparency ) # If we move to a new row, skip to the next full byte @@ -297,7 +315,7 @@ proc decodePng*(data: seq[uint8]): Image = counts = ChunkCounts() header: PngHeader palette: seq[array[3, uint8]] - imageData: seq[uint8] + transparency, imageData: seq[uint8] prevChunkType: string # First chunk must be IHDR @@ -333,9 +351,26 @@ proc decodePng*(data: seq[uint8]): Image = failInvalid() of "PLTE": inc counts.PLTE - if counts.PLTE > 1 or counts.IDAT > 0: + if counts.PLTE > 1 or counts.IDAT > 0 or counts.tRNS > 0: failInvalid() palette = parsePalette(data[pos ..< pos + chunkLen]) + of "tRNS": + inc counts.tRNS + if counts.tRNS > 1 or counts.IDAT > 0: + failInvalid() + transparency = data[pos ..< pos + chunkLen] + case header.colorType: + of 0: + if transparency.len != 2: + failInvalid() + of 2: + if transparency.len != 6: + failInvalid() + of 3: + if transparency.len > palette.len: + failInvalid() + else: + failInvalid() of "IDAT": inc counts.IDAT if counts.IDAT > 1 and prevChunkType != "IDAT": @@ -372,7 +407,7 @@ proc decodePng*(data: seq[uint8]): Image = result = Image() result.width = header.width result.height = header.height - result.data = parseImageData(header, palette, imageData) + result.data = parseImageData(header, palette, transparency, imageData) proc decodePng*(data: string): Image {.inline.} = decodePng(cast[seq[uint8]](data)) diff --git a/tests/pngsuite.nim b/tests/pngsuite.nim index 474fed7..5aa4019 100644 --- a/tests/pngsuite.nim +++ b/tests/pngsuite.nim @@ -73,6 +73,109 @@ const "s39n3p04", # 39x39 paletted file, no interlacing # "s40i3p04", # 40x40 paletted file, interlaced "s40n3p04", # 40x40 paletted file, no interlacing + + # "bgai4a08", # 8 bit grayscale, alpha, no background chunk, interlaced + # "bgai4a16", # 16 bit grayscale, alpha, no background chunk, interlaced + "bgan6a08", # 3x8 bits rgb color, alpha, no background chunk + # "bgan6a16", # 3x16 bits rgb color, alpha, no background chunk + "bgbn4a08", # 8 bit grayscale, alpha, black background chunk + # "bggn4a16", # 16 bit grayscale, alpha, gray background chunk + "bgwn6a08", # 3x8 bits rgb color, alpha, white background chunk + # "bgyn6a16", # 3x16 bits rgb color, alpha, yellow background chunk + + # "tbbn0g04", # transparent, black background chunk + # # "tbbn2c16", # transparent, blue background chunk + "tbbn3p08", # transparent, black background chunk + # # "tbgn2c16", # transparent, green background chunk + "tbgn3p08", # transparent, light-gray background chunk + "tbrn2c08", # transparent, red background chunk + # # "tbwn0g16", # transparent, white background chunk + "tbwn3p08", # transparent, white background chunk + "tbyn3p08", # transparent, yellow background chunk + "tp0n0g08", # not transparent for reference (logo on gray) + "tp0n2c08", # not transparent for reference (logo on gray) + "tp0n3p08", # not transparent for reference (logo on gray) + "tp1n3p08", # transparent, but no background chunk + "tm3n3p02", # multiple levels of transparency, 3 entries + + # "g03n0g16", # grayscale, file-gamma = 0.35 + "g03n2c08", # color, file-gamma = 0.35 + "g03n3p04", # paletted, file-gamma = 0.35 + # "g04n0g16", # grayscale, file-gamma = 0.45 + "g04n2c08", # color, file-gamma = 0.45 + "g04n3p04", # paletted, file-gamma = 0.45 + # "g05n0g16", # grayscale, file-gamma = 0.55 + "g05n2c08", # color, file-gamma = 0.55 + "g05n3p04", # paletted, file-gamma = 0.55 + # "g07n0g16", # grayscale, file-gamma = 0.70 + "g07n2c08", # color, file-gamma = 0.70 + "g07n3p04", # paletted, file-gamma = 0.70 + # "g10n0g16", # grayscale, file-gamma = 1.00 + "g10n2c08", # color, file-gamma = 1.00 + "g10n3p04", # paletted, file-gamma = 1.00 + # "g25n0g16", # grayscale, file-gamma = 2.50 + "g25n2c08", # color, file-gamma = 2.50 + "g25n3p04", # paletted, file-gamma = 2.50 + + "f00n0g08", # grayscale, no interlacing, filter-type 0 + "f00n2c08", # color, no interlacing, filter-type 0 + "f01n0g08", # grayscale, no interlacing, filter-type 1 + "f01n2c08", # color, no interlacing, filter-type 1 + "f02n0g08", # grayscale, no interlacing, filter-type 2 + "f02n2c08", # color, no interlacing, filter-type 2 + "f03n0g08", # grayscale, no interlacing, filter-type 3 + "f03n2c08", # color, no interlacing, filter-type 3 + "f04n0g08", # grayscale, no interlacing, filter-type 4 + "f04n2c08", # color, no interlacing, filter-type 4 + "f99n0g04", # bit-depth 4, filter changing per scanline + + # "pp0n2c16", # six-cube palette-chunk in true-color image + "pp0n6a08", # six-cube palette-chunk in true-color+alpha image + "ps1n0g08", # six-cube suggested palette (1 byte) in grayscale image + # "ps1n2c16", # six-cube suggested palette (1 byte) in true-color image + "ps2n0g08", # six-cube suggested palette (2 bytes) in grayscale image + # "ps2n2c16", # six-cube suggested palette (2 bytes) in true-color image + + "ccwn2c08", # chroma chunk w:0.3127,0.3290 r:0.64,0.33 g:0.30,0.60 b:0.15,0.06 + "ccwn3p08", # chroma chunk w:0.3127,0.3290 r:0.64,0.33 g:0.30,0.60 b:0.15,0.06 + "cdfn2c08", # physical pixel dimensions, 8x32 flat pixels + "cdhn2c08", # physical pixel dimensions, 32x8 high pixels + "cdsn2c08", # physical pixel dimensions, 8x8 square pixels + "cdun2c08", # physical pixel dimensions, 1000 pixels per 1 meter + "ch1n3p04", # histogram 15 colors + "ch2n3p08", # histogram 256 colors + "cm0n0g04", # modification time, 01-jan-2000 12:34:56 + "cm7n0g04", # modification time, 01-jan-1970 00:00:00 + "cm9n0g04", # modification time, 31-dec-1999 23:59:59 + # "cs3n2c16", # color, 13 significant bits + "cs3n3p08", # paletted, 3 significant bits + "cs5n2c08", # color, 5 significant bits + "cs5n3p08", # paletted, 5 significant bits + "cs8n2c08", # color, 8 significant bits (reference) + "cs8n3p08", # paletted, 8 significant bits (reference) + "ct0n0g04", # no textual data + "ct1n0g04", # with textual data + "ctzn0g04", # with compressed textual data + "cten0g04", # international UTF-8, english + "ctfn0g04", # international UTF-8, finnish + "ctgn0g04", # international UTF-8, greek + "cthn0g04", # international UTF-8, hindi + "ctjn0g04", # international UTF-8, japanese + "exif2c08", # chunk with jpeg exif data + + # "oi1n0g16", # grayscale mother image with 1 idat-chunk + # "oi1n2c16", # color mother image with 1 idat-chunk + # "oi2n0g16", # grayscale image with 2 idat-chunks + # "oi2n2c16", # color image with 2 idat-chunks + # "oi4n0g16", # grayscale image with 4 unequal sized idat-chunks + # "oi4n2c16", # color image with 4 unequal sized idat-chunks + # "oi9n0g16", # grayscale image with all idat-chunks length one + # "oi9n2c16", # color image with all idat-chunks length one + + "z00n2c08", # color, no interlacing, compression level 0 (none) + "z03n2c08", # color, no interlacing, compression level 3 + "z06n2c08", # color, no interlacing, compression level 6 (default) + "z09n2c08", # color, no interlacing, compression level 9 (maximum) ] pngSuiteCorruptedFiles* = [