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fix predefined filters

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andri lim 2020-04-13 14:44:49 +07:00
parent 7c55ff3f9d
commit 5f0dd589be
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GPG Key ID: 31702AE10541E6B9
2 changed files with 28 additions and 23 deletions
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38
nimPNG.nim
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@ -41,7 +41,7 @@ type
LCT_GREY_ALPHA = 4, # greyscale with alpha: 8,16 bit LCT_GREY_ALPHA = 4, # greyscale with alpha: 8,16 bit
LCT_RGBA = 6 # RGB with alpha: 8,16 bit LCT_RGBA = 6 # RGB with alpha: 8,16 bit
PNGFilter0 = enum PNGFilter* = enum
FLT_NONE, FLT_NONE,
FLT_SUB, FLT_SUB,
FLT_UP, FLT_UP,
@ -976,7 +976,7 @@ proc addColorBits(output: var DataBuf, index, bits, input: int) =
if p == 0: output[idx] = chr(val) if p == 0: output[idx] = chr(val)
else: output[idx] = chr(ord(output[idx]) or val) else: output[idx] = chr(ord(output[idx]) or val)
proc unfilterScanLine(recon: var DataBuf, scanLine, precon: DataBuf, byteWidth, len: int, filterType: PNGFilter0) = proc unfilterScanLine(recon: var DataBuf, scanLine, precon: DataBuf, byteWidth, len: int, filterType: PNGFilter) =
# For PNG filter method 0 # For PNG filter method 0
# unfilter a PNG image scanLine by scanLine. when the pixels are smaller than 1 byte, # unfilter a PNG image scanLine by scanLine. when the pixels are smaller than 1 byte,
# the filter works byte per byte (byteWidth = 1) # the filter works byte per byte (byteWidth = 1)
@ -1033,7 +1033,7 @@ proc unfilter(output: var DataBuf, input: DataBuf, w, h, bpp: int) =
for y in 0..h-1: for y in 0..h-1:
let outIndex = lineBytes * y let outIndex = lineBytes * y
let inIndex = (1 + lineBytes) * y # the extra filterbyte added to each row let inIndex = (1 + lineBytes) * y # the extra filterbyte added to each row
let filterType = PNGFilter0(input[inindex]) let filterType = PNGFilter(input[inindex])
let scanLine = input.subbuffer(inIndex + 1) let scanLine = input.subbuffer(inIndex + 1)
var outp = output.subbuffer(outIndex) var outp = output.subbuffer(outIndex)
unfilterScanLine(outp, scanLine, prevLine, byteWidth, lineBytes, filterType) unfilterScanLine(outp, scanLine, prevLine, byteWidth, lineBytes, filterType)
@ -2101,7 +2101,7 @@ type
#used if filter_strategy is LFS_PREDEFINED. In that case, this must point to a buffer with #used if filter_strategy is LFS_PREDEFINED. In that case, this must point to a buffer with
#the same length as the amount of scanLines in the image, and each value must <= 5. #the same length as the amount of scanLines in the image, and each value must <= 5.
#Don't forget that filter_palette_zero must be set to false to ensure this is also used on palette or low bitdepth images. #Don't forget that filter_palette_zero must be set to false to ensure this is also used on palette or low bitdepth images.
predefinedFilters*: string predefinedFilters*: seq[PNGFilter]
#force creating a PLTE chunk if colorType is 2 or 6 (= a suggested palette). #force creating a PLTE chunk if colorType is 2 or 6 (= a suggested palette).
#If colorType is 3, PLTE is _always_ created. #If colorType is 3, PLTE is _always_ created.
@ -2153,7 +2153,7 @@ proc makePNGEncoder*(): PNGEncoder =
s.modeIn = newColorMode() s.modeIn = newColorMode()
s.modeOut = newColorMode() s.modeOut = newColorMode()
s.forcePalette = false s.forcePalette = false
s.predefinedFilters = "" s.predefinedFilters = @[]
s.addID = false s.addID = false
s.textCompression = true s.textCompression = true
s.interlaceMethod = IM_NONE s.interlaceMethod = IM_NONE
@ -2675,7 +2675,7 @@ proc addPaddingBits(output: var DataBuf, input: DataBuf, olinebits, ilinebits, h
setBitOfReversedStream(obp, output, bit) setBitOfReversedStream(obp, output, bit)
for x in 0..diff-1: setBitOfReversedStream(obp, output, 0) for x in 0..diff-1: setBitOfReversedStream(obp, output, 0)
proc filterScanLine(output: var DataBuf, scanLine, prevLine: DataBuf, len, byteWidth: int, filterType: PNGFilter0) = proc filterScanLine(output: var DataBuf, scanLine, prevLine: DataBuf, len, byteWidth: int, filterType: PNGFilter) =
case filterType case filterType
of FLT_NONE: of FLT_NONE:
for i in 0..len-1: output[i] = scanLine[i] for i in 0..len-1: output[i] = scanLine[i]
@ -2748,7 +2748,7 @@ proc filterMinsum(output: var DataBuf, input: DataBuf, w, h, bpp: int) =
#try the 5 filter types #try the 5 filter types
for fType in 0..4: for fType in 0..4:
var outp = initBuffer(attempt[fType]) var outp = initBuffer(attempt[fType])
filterScanLine(outp, input.subbuffer(y * lineBytes), prevLine, lineBytes, byteWidth, PNGFilter0(fType)) filterScanLine(outp, input.subbuffer(y * lineBytes), prevLine, lineBytes, byteWidth, PNGFilter(fType))
#calculate the sum of the result #calculate the sum of the result
sum[fType] = 0 sum[fType] = 0
if fType == 0: if fType == 0:
@ -2793,7 +2793,7 @@ proc filterEntropy(output: var DataBuf, input: DataBuf, w, h, bpp: int) =
#try the 5 filter types #try the 5 filter types
for fType in 0..4: for fType in 0..4:
var outp = initBuffer(attempt[fType]) var outp = initBuffer(attempt[fType])
filterScanLine(outp, input.subbuffer(y * lineBytes), prevLine, lineBytes, byteWidth, PNGFilter0(fType)) filterScanLine(outp, input.subbuffer(y * lineBytes), prevLine, lineBytes, byteWidth, PNGFilter(fType))
for x in 0..255: count[x] = 0 for x in 0..255: count[x] = 0
for x in 0..lineBytes-1: for x in 0..lineBytes-1:
inc count[ord(attempt[fType][x])] inc count[ord(attempt[fType][x])]
@ -2826,7 +2826,7 @@ proc filterPredefined(output: var DataBuf, input: DataBuf, w, h, bpp: int, state
let fType = ord(state.predefinedFilters[y]) let fType = ord(state.predefinedFilters[y])
output[outindex] = chr(fType) #filter type byte output[outindex] = chr(fType) #filter type byte
var outp = output.subbuffer(outindex + 1) var outp = output.subbuffer(outindex + 1)
filterScanLine(outp, input.subbuffer(inindex), prevLine, lineBytes, byteWidth, PNGFilter0(fType)) filterScanLine(outp, input.subbuffer(inindex), prevLine, lineBytes, byteWidth, PNGFilter(fType))
prevLine = input.subbuffer(inindex) prevLine = input.subbuffer(inindex)
proc filterBruteForce(output: var DataBuf, input: DataBuf, w, h, bpp: int) = proc filterBruteForce(output: var DataBuf, input: DataBuf, w, h, bpp: int) =
@ -2856,7 +2856,7 @@ proc filterBruteForce(output: var DataBuf, input: DataBuf, w, h, bpp: int) =
for fType in 0..4: for fType in 0..4:
#let testSize = attempt[fType].len #let testSize = attempt[fType].len
var outp = initBuffer(attempt[fType]) var outp = initBuffer(attempt[fType])
filterScanline(outp, input.subbuffer(y * lineBytes), prevLine, lineBytes, byteWidth, PNGFilter0(fType)) filterScanline(outp, input.subbuffer(y * lineBytes), prevLine, lineBytes, byteWidth, PNGFilter(fType))
size[fType] = 0 size[fType] = 0
var nz = nzDeflateInit(attempt[fType]) var nz = nzDeflateInit(attempt[fType])
@ -3385,24 +3385,24 @@ when not defined(js):
debugEcho getCurrentExceptionMsg() debugEcho getCurrentExceptionMsg()
result = false result = false
proc getFilterTypesInterlaced(png: PNG): seq[string] = proc getFilterTypesInterlaced(png: PNG): seq[seq[PNGFilter]] =
var header = PNGHeader(png.getChunk(IHDR)) var header = PNGHeader(png.getChunk(IHDR))
var idat = PNGData(png.getChunk(IDAT)) var idat = PNGData(png.getChunk(IDAT))
if header.interlaceMethod == IM_NONE: if header.interlaceMethod == IM_NONE:
result = newSeq[string](1) result = newSeq[seq[PNGFilter]](1)
result[0] = "" result[0] = @[]
#A line is 1 filter byte + all pixels #A line is 1 filter byte + all pixels
let lineBytes = 1 + idatRawSize(header.width, 1, header) let lineBytes = 1 + idatRawSize(header.width, 1, header)
var i = 0 var i = 0
while i < idat.idat.len: while i < idat.idat.len:
result[0].add idat.idat[i] result[0].add PNGFilter(idat.idat[i].int)
inc(i, lineBytes) inc(i, lineBytes)
else: else:
result = newSeq[string](7) result = newSeq[seq[PNGFilter]](7)
for j in 0..6: for j in 0..6:
result[j] = "" result[j] = @[]
var w2 = (header.width - ADAM7_IX[j] + ADAM7_DX[j] - 1) div ADAM7_DX[j] var w2 = (header.width - ADAM7_IX[j] + ADAM7_DX[j] - 1) div ADAM7_DX[j]
var h2 = (header.height - ADAM7_IY[j] + ADAM7_DY[j] - 1) div ADAM7_DY[j] var h2 = (header.height - ADAM7_IY[j] + ADAM7_DY[j] - 1) div ADAM7_DY[j]
if(ADAM7_IX[j] >= header.width) or (ADAM7_IY[j] >= header.height): if(ADAM7_IX[j] >= header.width) or (ADAM7_IY[j] >= header.height):
@ -3412,10 +3412,10 @@ proc getFilterTypesInterlaced(png: PNG): seq[string] =
let lineBytes = 1 + idatRawSize(w2, 1, header) let lineBytes = 1 + idatRawSize(w2, 1, header)
var pos = 0 var pos = 0
for i in 0..h2-1: for i in 0..h2-1:
result[j].add idat.idat[pos] result[j].add PNGFilter(idat.idat[pos].int)
inc(pos, linebytes) inc(pos, linebytes)
proc getFilterTypes*(png: PNG): string = proc getFilterTypes*(png: PNG): seq[PNGFilter] =
var passes = getFilterTypesInterlaced(png) var passes = getFilterTypesInterlaced(png)
if passes.len == 1: if passes.len == 1:
@ -3425,7 +3425,7 @@ proc getFilterTypes*(png: PNG): string =
#Interlaced. Simplify it: put pass 6 and 7 alternating in the one vector so #Interlaced. Simplify it: put pass 6 and 7 alternating in the one vector so
#that one filter per scanline of the uninterlaced image is given, with that #that one filter per scanline of the uninterlaced image is given, with that
#filter corresponding the closest to what it would be for non-interlaced image. #filter corresponding the closest to what it would be for non-interlaced image.
result = "" result = @[]
for i in 0..header.height-1: for i in 0..header.height-1:
if (i mod 2) == 0: result.add passes[5][i div 2] if (i mod 2) == 0: result.add passes[5][i div 2]
else: result.add passes[6][i div 2] else: result.add passes[6][i div 2]

11
tests/test_codec.nim
View File

@ -438,7 +438,7 @@ proc testPaletteFilterTypesZero() =
assertEquals(17, filterTypes.len) assertEquals(17, filterTypes.len)
for i in 0..16: for i in 0..16:
assertEquals(0.chr, filterTypes[i]) assertEquals(FLT_NONE, filterTypes[i])
proc testComplexPNG() = proc testComplexPNG() =
echo "testComplexPNG" echo "testComplexPNG"
@ -485,13 +485,18 @@ proc testPredefinedFilters() =
var state = makePNGEncoder() var state = makePNGEncoder()
state.filterStrategy = LFS_PREDEFINED state.filterStrategy = LFS_PREDEFINED
state.filterPaletteZero = false state.filterPaletteZero = false
state.predefinedFilters = repeat(chr(3), h) #everything to filter type '3'
# everything to filter type 'FLT_AVERAGE'
state.predefinedFilters = newSeq[PNGFilter](h)
for i in 0..<h:
state.predefinedFilters[i] = FLT_AVERAGE
var png = encodePNG(image.data, w, h, state) var png = encodePNG(image.data, w, h, state)
var outFilters = png.getFilterTypes() var outFilters = png.getFilterTypes()
assertEquals(h, outFilters.len) assertEquals(h, outFilters.len)
for i in 0..<h: for i in 0..<h:
assertEquals(chr(3), outFilters[i]) assertEquals(FLT_AVERAGE, outFilters[i])
# Tests combinations of various colors in different orders # Tests combinations of various colors in different orders
proc testFewColors() = proc testFewColors() =