ppm consistent style pass
This commit is contained in:
Ryan Oldenburg
parent
2caed5f5ae
commit
be57c71c3c
2 changed files with 50 additions and 35 deletions
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@ -16,9 +16,10 @@ proc decodeHeader(data: string): PpmHeader {.raises: [PixieError].} =
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if data.len <= 10: # Each part + whitespace
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raise newException(PixieError, "Invalid PPM file header")
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var commentMode, readWhitespace: bool
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var i, readFields: int
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var field: string
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var
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commentMode, readWhitespace: bool
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i, readFields: int
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field: string
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while readFields < 4:
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let c = readUint8(data, i).char
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if c == '#':
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@ -41,7 +42,8 @@ proc decodeHeader(data: string): PpmHeader {.raises: [PixieError].} =
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result.maxVal = parseInt(field)
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else:
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discard
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except ValueError: failInvalid()
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except ValueError:
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failInvalid()
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field = ""
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elif not (c in Whitespace):
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field.add(c)
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@ -54,49 +56,64 @@ proc decodeP6Data(data: string, maxVal: int): seq[ColorRGBX] {.raises: [].} =
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let needsUint16 = maxVal > 0xFF
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result = newSeq[ColorRGBX](
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if needsUint16: data.len div 6
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else: data.len div 3
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if needsUint16:
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data.len div 6
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else:
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data.len div 3
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)
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# Let's calculate the real maximum value multiplier.
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# rgbx() accepts a maximum value of 0xFF. Most of the time,
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# maxVal is set to 0xFF as well, so in most cases it is 1
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let valueMultiplier = 0xFF / maxVal
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# rgbx() accepts a maximum value of 255. Most of the time,
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# maxVal is set to 255 as well, so in most cases it is 1
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let valueMultiplier = (255 / maxVal).float32
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# if comparison in for loops is expensive, so let's unroll it
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if not needsUint16:
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for i in 0 ..< result.len:
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let
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red = (readUint8(data, i + (i * 2)).float * valueMultiplier + 0.5).uint8
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green = (readUint8(data, i + 1 + (i * 2)).float * valueMultiplier + 0.5).uint8
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blue = (readUint8(data, i + 2 + (i * 2)).float * valueMultiplier + 0.5).uint8
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result[i] = rgbx(red, green, blue, 0xFF)
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red = data.readUint8(i + (i * 2)).float32
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green = data.readUint8(i + 1 + (i * 2)).float32
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blue = data.readUint8(i + 2 + (i * 2)).float32
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result[i] = rgbx(
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(red * valueMultiplier + 0.5).uint8,
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(green * valueMultiplier + 0.5).uint8,
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(blue * valueMultiplier + 0.5).uint8,
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255
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)
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else:
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for i in 0 ..< result.len:
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let
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red = (readUint16(data, i + (i * 5)).swap.float * valueMultiplier + 0.5).uint8
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green = (readUint16(data, i + 2 + (i * 5)).swap.float * valueMultiplier + 0.5).uint8
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blue = (readUint16(data, i + 4 + (i * 5)).swap.float * valueMultiplier + 0.5).uint8
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result[i] = rgbx(red, green, blue, 0xFF)
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red = data.readUint16(i + (i * 5)).swap.float32
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green = data.readUint16(i + 2 + (i * 5)).swap.float32
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blue = data.readUint16(i + 4 + (i * 5)).swap.float32
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result[i] = rgbx(
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(red * valueMultiplier + 0.5).uint8,
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(green * valueMultiplier + 0.5).uint8,
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(blue * valueMultiplier + 0.5).uint8,
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255
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)
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proc decodeP3Data(data: string, maxVal: int): seq[ColorRGBX] {.raises: [PixieError].} =
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let needsUint16 = maxVal > 0xFF
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let maxLen = (
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if needsUint16: data.splitWhitespace.len * 2
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else: data.splitWhitespace.len
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)
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var p6data = newStringOfCap(maxLen)
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let
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needsUint16 = maxVal > 0xFF
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maxLen =
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if needsUint16:
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data.splitWhitespace.len * 2
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else:
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data.splitWhitespace.len
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var p6data = newStringOfCap(maxLen)
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try:
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if not needsUint16:
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for line in data.splitLines():
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for sample in line.split('#', 1)[0].splitWhitespace():
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p6data.add(parseInt(sample).chr)
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p6data.add(parseInt(sample).char)
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else:
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for line in data.splitLines():
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for sample in line.split('#', 1)[0].splitWhitespace():
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p6data.addUint16(parseInt(sample).uint16.swap)
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except ValueError: failInvalid()
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except ValueError:
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failInvalid()
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result = decodeP6Data(p6data, maxVal)
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@ -105,20 +122,20 @@ proc decodePpm*(data: string): Image {.raises: [PixieError].} =
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let header = decodeHeader(data)
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if not (header.version in ppmSignatures): failInvalid()
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if 0 > header.maxVal or header.maxVal > 0xFFFF: failInvalid()
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if not (header.version in ppmSignatures):
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failInvalid()
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if 0 > header.maxVal or header.maxVal > 0xFFFF:
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failInvalid()
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result = newImage(header.width, header.height)
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result.data = (
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if header.version == "P3":
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decodeP3Data(data[header.dataOffset .. ^1], header.maxVal)
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else: decodeP6Data(data[header.dataOffset .. ^1], header.maxVal)
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else:
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decodeP6Data(data[header.dataOffset .. ^1], header.maxVal)
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)
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proc decodePpm*(data: seq[uint8]): Image {.inline, raises: [PixieError].} =
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## Decodes Portable Pixel Map data into an Image.
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decodePpm(cast[string](data))
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proc encodePpm*(image: Image): string {.raises: [].} =
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## Encodes an image into the PPM file format (version P6).
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@ -7,9 +7,7 @@ block:
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))
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writeFile("tests/fileformats/ppm/feep." & $format & ".ppm", encodePpm(image))
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let image = decodePpm(readFile(
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"tests/fileformats/ppm/feep.p3.hidepth.master.ppm"
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))
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let image = decodePpm(readFile("tests/fileformats/ppm/feep.p3.hidepth.master.ppm"))
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writeFile("tests/fileformats/ppm/feep.p3.hidepth.ppm", encodePpm(image))
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# produced output should be identical to P6 master
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