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flip loop and case order

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This commit is contained in:
Ryan Oldenburg 2020-11-20 21:56:06 -06:00
parent 0458b4c6e5
commit fbce3f50db
1 changed files with 55 additions and 31 deletions
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86
src/pixie/fileformats/png.nim
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@ -173,12 +173,11 @@ proc parseImageData(
max(valuesPerPixel div valuesPerByte, 1)
)
var bytePos, bitPos: int
for y in 0 ..< header.height:
for x in 0 ..< header.width:
var rgba: array[4, uint8]
case header.colorType:
of 0:
case header.colorType:
of 0:
var bytePos, bitPos: int
for y in 0 ..< header.height:
for x in 0 ..< header.width:
var value = unfiltered[bytePos]
case header.bitDepth:
of 1:
@ -201,12 +200,28 @@ proc parseImageData(
if bitPos == 8:
inc bytePos
bitPos = 0
rgba = [value, value, value, 255]
of 2:
result[x + y * header.width] = ColorRGBA(
r: value, g: value, b: value, a: 255
)
# If we move to a new row, skip to the next full byte
if bitPos > 0:
inc bytePos
bitPos = 0
of 2:
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)[]
rgba = [rgb[0], rgb[1], rgb[2], 255]
inc(bytePos, 3)
of 3:
result[x + y * header.width] = ColorRGBA(
r: rgb[0], g: rgb[1], b: rgb[2], a: 255
)
bytePos += 3
of 3:
var bytePos, bitPos: int
for y in 0 ..< header.height:
for x in 0 ..< header.width:
var value = unfiltered[bytePos]
case header.bitDepth:
of 1:
@ -228,28 +243,37 @@ proc parseImageData(
bitPos = 0
if value.int >= palette.len:
failInvalid()
let rgb = palette[value]
rgba = [rgb[0], rgb[1], rgb[2], 255]
of 4:
rgba = [
unfiltered[bytePos],
unfiltered[bytePos],
unfiltered[bytePos],
unfiltered[bytePos + 1]
]
inc(bytePos, 2)
of 6:
rgba = cast[array[4, uint8]](unfiltered.readUint32(bytePos))
inc(bytePos, 4)
else:
discard # Not possible, parseHeader validates
result[x + y * header.width] = ColorRGBA(
r: rgb[0], g: rgb[1], b: rgb[2], a: 255
)
result[x + y * header.width] = cast[ColorRGBA](rgba)
# If we move to a new row, skip to the next full byte
if bitPos > 0:
inc bytePos
bitPos = 0
# If we move to a new row, skip to the next full byte
if bitPos > 0:
inc bytePos
bitPos = 0
of 4:
var bytePos: int
for y in 0 ..< header.height:
for x in 0 ..< header.width:
result[x + y * header.width] = ColorRGBA(
r: unfiltered[bytePos],
g: unfiltered[bytePos],
b: unfiltered[bytePos],
a: unfiltered[bytePos + 1]
)
bytePos += 2
of 6:
var bytePos: int
for y in 0 ..< header.height:
for x in 0 ..< header.width:
result[x + y * header.width] = cast[ColorRGBA](
unfiltered.readUint32(bytePos)
)
bytePos += 4
else:
discard # Not possible, parseHeader validates
proc decodePng*(data: seq[uint8]): Image =
## Decodes the PNG from the parameter buffer. Check png.channels and