Simpler upscaling code.
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1 changed files with 96 additions and 193 deletions
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@ -1,4 +1,4 @@
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import pixie/common, pixie/images, sequtils, strutils
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import pixie/common, pixie/images, pixie/masks, sequtils, strutils, chroma
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# This JPEG decoder is loosely based on stb_image which is public domain.
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@ -68,8 +68,9 @@ type
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huffmanDC, huffmanAC: int
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dcPred: int
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widthCoeff, heightCoeff: int
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data, coeff, lineBuf: seq[uint8]
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coeff, lineBuf: seq[uint8]
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blocks: seq[seq[array[64, int16]]]
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channel: Mask
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DecoderState = object
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buffer: seq[uint8]
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@ -91,6 +92,9 @@ type
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todo: int
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eobRun: int
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when defined(release):
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{.push checks: off.}
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template failInvalid(reason = "unable to load") =
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## Throw exception with a reason.
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raise newException(PixieError, "Invalid JPEG, " & reason)
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@ -299,8 +303,8 @@ proc decodeSOF0(state: var DecoderState) =
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state.components[i].heightStride =
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state.numMcuHigh * state.components[i].xScale * 8
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state.components[i].data.setLen(
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state.components[i].widthStride * state.components[i].heightStride
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state.components[i].channel = newMask(
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state.components[i].widthStride, state.components[i].heightStride
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)
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if state.progressive:
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@ -760,14 +764,14 @@ proc idctBlock(component: var Component, offset: int, data: array[64, int16]) =
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x2 += 65536 + (128 shl 17)
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x3 += 65536 + (128 shl 17)
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component.data[outPos + 0] = clampByte((x0 + t3) shr 17)
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component.data[outPos + 7] = clampByte((x0 - t3) shr 17)
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component.data[outPos + 1] = clampByte((x1 + t2) shr 17)
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component.data[outPos + 6] = clampByte((x1 - t2) shr 17)
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component.data[outPos + 2] = clampByte((x2 + t1) shr 17)
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component.data[outPos + 5] = clampByte((x2 - t1) shr 17)
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component.data[outPos + 3] = clampByte((x3 + t0) shr 17)
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component.data[outPos + 4] = clampByte((x3 - t0) shr 17)
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component.channel.data[outPos + 0] = clampByte((x0 + t3) shr 17)
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component.channel.data[outPos + 7] = clampByte((x0 - t3) shr 17)
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component.channel.data[outPos + 1] = clampByte((x1 + t2) shr 17)
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component.channel.data[outPos + 6] = clampByte((x1 - t2) shr 17)
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component.channel.data[outPos + 2] = clampByte((x2 + t1) shr 17)
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component.channel.data[outPos + 5] = clampByte((x2 - t1) shr 17)
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component.channel.data[outPos + 3] = clampByte((x3 + t0) shr 17)
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component.channel.data[outPos + 4] = clampByte((x3 - t0) shr 17)
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{.pop.}
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@ -857,199 +861,95 @@ proc quantizationAndIDCTPass(state: var DecoderState) =
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data
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)
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proc resampleRowH1V1(
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dst, a, b: ptr UncheckedArray[uint8],
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widthPreExpansion, horizontalExpansionFactor: int
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): ptr UncheckedArray[uint8] =
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a
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proc resampleRowH1V2(
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dst, a, b: ptr UncheckedArray[uint8],
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widthPreExpansion, horizontalExpansionFactor: int
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): ptr UncheckedArray[uint8] =
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for i in 0 ..< widthPreExpansion:
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dst[i] = ((3 * a[i].int + b[i].int + 2) shr 2).uint8
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dst
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proc resampleRowH2V1(
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dst, a, b: ptr UncheckedArray[uint8],
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widthPreExpansion, horizontalExpansionFactor: int
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): ptr UncheckedArray[uint8] =
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if widthPreExpansion == 1:
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dst[0] = a[0]
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dst[1] = dst[0]
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else:
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dst[0] = a[0]
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dst[1] = ((a[0].int * 3 + a[1].int + 2) shr 2).uint8
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for i in 1 ..< widthPreExpansion - 1:
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let n = 3 * a[i].int + 2
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dst[i * 2 + 0] = ((n + a[i - 1].int) shr 2).uint8
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dst[i * 2 + 1] = ((n + a[i + 1].int) shr 2).uint8
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dst[widthPreExpansion * 2 + 0] = ((
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a[widthPreExpansion - 2].int * 3 + a[widthPreExpansion - 1].int + 2
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) shr 2).uint8
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dst[widthPreExpansion * 2 + 1] = (a[widthPreExpansion - 1]) shr 2
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dst
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proc resampleRowH4V1(
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dst, a, b: ptr UncheckedArray[uint8],
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widthPreExpansion, horizontalExpansionFactor: int
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): ptr UncheckedArray[uint8] =
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for i in 0 ..< widthPreExpansion * 4:
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dst[i] = a[i div 4]
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dst
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proc resampleRowH2V2(
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dst, a, b: ptr UncheckedArray[uint8],
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widthPreExpansion, horizontalExpansionFactor: int
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): ptr UncheckedArray[uint8] =
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if widthPreExpansion == 1:
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dst[0] = ((3 * a[0].int + b[0].int + 2) shr 2).uint8
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dst[1] = dst[0]
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else:
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var
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t0: int
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t1 = 3 * a[0].int + b[0].int
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dst[0] = ((t1 + 2) shr 2).uint8
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for i in 1 ..< widthPreExpansion:
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t0 = t1
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t1 = 3 * a[i].int + b[i].int
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dst[i * 2 - 1] = ((3 * t0 + t1 + 8) shr 4).uint8
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dst[i * 2 + 0] = ((3 * t1 + t0 + 8) shr 4).uint8
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dst[widthPreExpansion * 2 - 1] = ((t1 + 2) shr 2).uint8
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dst
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proc yCbCrToRgbx(dst, py, pcb, pcr: ptr UncheckedArray[uint8], width: int) =
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proc yCbCrToRgbx(py, pcb, pcr: uint8): ColorRGBX =
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## Takes a 3 component yCbCr outputs and populates image.
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template float2Fixed(x: float32): int =
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(x * 4096 + 0.5).int shl 8
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var pos: int
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for i in 0 ..< width:
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let
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yFixed = (py[][i].int shl 20) + (1 shl 19)
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cb = pcb[][i].int - 128
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cr = pcr[][i].int - 128
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var
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r = yFixed + cr * float2Fixed(1.40200)
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g = yFixed +
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(cr * -float2Fixed(0.71414)) +
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((cb * -float2Fixed(0.34414)) and -65536)
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b = yFixed + cb * float2Fixed(1.77200)
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dst[pos + 0] = clampByte(r shr 20)
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dst[pos + 1] = clampByte(g shr 20)
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dst[pos + 2] = clampByte(b shr 20)
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dst[pos + 3] = 255
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pos += 4
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let
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yFixed = (py.int shl 20) + (1 shl 19)
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cb = pcb.int - 128
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cr = pcr.int - 128
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var
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r = yFixed + cr * float2Fixed(1.40200)
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g = yFixed +
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(cr * -float2Fixed(0.71414)) +
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((cb * -float2Fixed(0.34414)) and -65536)
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b = yFixed + cb * float2Fixed(1.77200)
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result.r = clampByte(r shr 20)
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result.g = clampByte(g shr 20)
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result.b = clampByte(b shr 20)
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result.a = 255
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proc grayScaleToRgbx(dst, gray: ptr UncheckedArray[uint8], width: int) =
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proc grayScaleToRgbx(gray: uint8): ColorRGBX =
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## Takes a single gray scale component output and populates image.
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var pos: int
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for i in 0 ..< width:
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let g = gray[i]
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dst[pos + 0] = g
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dst[pos + 1] = g
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dst[pos + 2] = g
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dst[pos + 3] = 255
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pos += 4
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let g = gray
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result.r = g
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result.g = g
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result.b = g
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result.a = 255
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proc magnifyXBy2(mask: Mask): Mask =
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result = newMask(mask.width * 2, mask.height)
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for y in 0 ..< mask.height:
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for x in 0 ..< mask.width:
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if x == 0 or x == mask.width - 1:
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result[x * 2 + 0, y] = mask[x, y]
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result[x * 2 + 1, y] = mask[x, y]
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else:
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result[x * 2 + 0, y] = mask[x, y] div 2 + mask[x-1, y] div 2
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result[x * 2 + 1, y] = mask[x, y] div 2 + mask[x+1, y] div 2
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proc magnifyYBy2(mask: Mask): Mask =
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result = newMask(mask.width, mask.height * 2)
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for y in 0 ..< mask.height:
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for x in 0 ..< mask.width:
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if y == 0 or y == mask.width - 1:
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result[x, y * 2 + 0] = mask[x, y]
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result[x, y * 2 + 1] = mask[x, y]
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else:
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result[x, y * 2 + 0] = mask[x, y] div 2 + mask[x, y-1] div 2
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result[x, y * 2 + 1] = mask[x, y] div 2 + mask[x, y+1] div 2
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proc buildImage(state: var DecoderState): Image =
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## Takes a jpeg image object and builds a pixie Image from it.
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if state.components.len == 3:
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for componentIdx, component in state.components.mpairs:
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while component.xScale < state.maxXScale:
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component.channel = component.channel.magnifyYBy2()
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component.xScale *= 2
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while component.yScale < state.maxYScale:
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component.channel = component.channel.magnifyXBy2()
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component.yScale *= 2
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result = newImage(state.imageWidth, state.imageHeight)
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var resamples: array[3, Resample]
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for i in 0 ..< state.components.len:
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resamples[i].horizontalExpansionFactor =
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state.maxYScale div
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state.components[i].yScale
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resamples[i].verticalExpansionFactor =
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state.maxXScale div
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state.components[i].xScale
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resamples[i].yStep = resamples[i].verticalExpansionFactor shr 1
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resamples[i].widthPreExpansion = (
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state.imageWidth + resamples[i].horizontalExpansionFactor - 1
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) div resamples[i].horizontalExpansionFactor
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if state.components.len == 3:
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let
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cy = state.components[0].channel
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cb = state.components[1].channel
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cr = state.components[2].channel
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for y in 0 ..< state.imageHeight:
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for x in 0 ..< state.imageWidth:
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result[x, y] = yCbCrToRgbx(
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cy[x, y],
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cb[x, y],
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cr[x, y],
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)
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resamples[i].line0 = cast[ptr UncheckedArray[uint8]](
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state.components[i].data[0].addr
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)
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resamples[i].line1 = cast[ptr UncheckedArray[uint8]](
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state.components[i].data[0].addr
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)
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state.components[i].lineBuf.setLen(state.imageWidth + 3)
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if resamples[i].horizontalExpansionFactor == 1 and
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resamples[i].verticalExpansionFactor == 1:
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resamples[i].resample = resampleRowH1V1
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elif resamples[i].horizontalExpansionFactor == 1 and
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resamples[i].verticalExpansionFactor == 2:
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resamples[i].resample = resampleRowH1V2
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elif resamples[i].horizontalExpansionFactor == 2 and
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resamples[i].verticalExpansionFactor == 1:
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resamples[i].resample = resampleRowH2V1
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elif resamples[i].horizontalExpansionFactor == 2 and
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resamples[i].verticalExpansionFactor == 2:
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resamples[i].resample = resampleRowH2V2
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elif resamples[i].horizontalExpansionFactor == 4 and
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resamples[i].verticalExpansionFactor == 1:
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resamples[i].resample = resampleRowH4V1
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else:
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failInvalid()
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for y in 0 ..< state.imageHeight:
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var componentOutputs: seq[ptr UncheckedArray[uint8]]
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for i in 0 ..< state.components.len:
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let yBottom =
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resamples[i].yStep >= (resamples[i].verticalExpansionFactor shr 1)
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# TODO
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# for x in sample ^ 2
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# resample x dir
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# for y in sample ^ 2
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# resample y dir
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componentOutputs.add resamples[i].resample(
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cast[ptr UncheckedArray[uint8]](state.components[i].lineBuf[0].addr),
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if yBottom: resamples[i].line1 else: resamples[i].line0,
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if yBottom: resamples[i].line0 else: resamples[i].line1,
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resamples[i].widthPreExpansion,
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resamples[i].horizontalExpansionFactor
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)
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inc resamples[i].yStep
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if resamples[i].yStep >= resamples[i].verticalExpansionFactor:
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resamples[i].yStep = 0
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resamples[i].line0 = resamples[i].line1
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inc resamples[i].yPos
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if resamples[i].yPos < state.components[i].height:
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resamples[i].line1 = cast[ptr UncheckedArray[uint8]](
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state.components[i].data[
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resamples[i].yPos * state.components[i].widthStride
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].addr
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)
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let dst = cast[ptr UncheckedArray[uint8]](
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result.data[state.imageWidth * y].addr
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)
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if state.components.len == 3:
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yCbCrToRgbx(
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dst,
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componentOutputs[0],
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componentOutputs[1],
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componentOutputs[2],
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state.imageWidth
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)
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elif state.components.len == 1:
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grayScaleToRgbx(
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dst,
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componentOutputs[0],
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state.imageWidth,
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)
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else:
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failInvalid()
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elif state.components.len == 1:
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let
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cy = state.components[0].channel
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for y in 0 ..< state.imageHeight:
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for x in 0 ..< state.imageWidth:
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result[x, y] = grayScaleToRgbx(
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cy[x, y],
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)
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else:
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failInvalid()
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proc decodeJpeg*(data: seq[uint8]): Image {.raises: [PixieError].} =
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## Decodes the JPEG into an Image.
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@ -1121,3 +1021,6 @@ proc decodeJpeg*(data: string): Image {.inline, raises: [PixieError].} =
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proc encodeJpeg*(image: Image): string =
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raise newException(PixieError, "Encoding JPG not supported yet")
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when defined(release):
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{.pop.}
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