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faster on arc, arc string []= issue 18339

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This commit is contained in:
Ryan Oldenburg 2022-06-15 14:03:28 -05:00
parent ff45edf131
commit 5afa5720db
1 changed files with 6 additions and 6 deletions
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12
src/pixie/fileformats/png.nim
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@ -94,7 +94,7 @@ proc decodePalette(data: pointer, len: int): seq[ColorRGB] =
proc unfilter(
uncompressed: string, height, rowBytes, bpp: int
): string =
): seq[uint8] =
result.setLen(uncompressed.len - height)
template uncompressedIdx(x, y: int): int =
@ -121,7 +121,7 @@ proc unfilter(
var value = uncompressed.readUint8(uncompressedStartIdx + x)
if x - bpp >= 0:
value += result.readUint8(unfilteredStartIx + x - bpp)
result[unfilteredStartIx + x] = value.char
result[unfilteredStartIx + x] = value
of 2: # Up
let
uncompressedStartIdx = uncompressedIdx(1, y)
@ -129,8 +129,8 @@ proc unfilter(
for x in 0 ..< rowBytes:
var value = uncompressed.readUint8(uncompressedStartIdx + x)
if y - 1 >= 0:
value += result.readUint8(unfiteredIdx(x, y - 1))
result[unfilteredStartIx + x] = value.char
value += result.readUint8(unfilteredStartIx + x - rowBytes)
result[unfilteredStartIx + x] = value
of 3: # Average
let
uncompressedStartIdx = uncompressedIdx(1, y)
@ -144,7 +144,7 @@ proc unfilter(
if y - 1 >= 0:
up = result[unfilteredStartIx + x - rowBytes].int
value += ((left + up) div 2).uint8
result[unfilteredStartIx + x] = value.char
result[unfilteredStartIx + x] = value
of 4: # Paeth
let
uncompressedStartIdx = uncompressedIdx(1, y)
@ -172,7 +172,7 @@ proc unfilter(
else:
c
value += paethPredictor(up, left, upLeft).uint8
result[unfilteredStartIx + x] = value.char
result[unfilteredStartIx + x] = value
else:
discard # Not possible, parseHeader validates