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# A PSDImage stores parsed image data for images contained within the PSD, and
# for the PSD itself.
class PSDImage
COMPRESSIONS =
0: 'Raw'
1: 'RLE'
2: 'ZIP'
3: 'ZIPPrediction'
channelsInfo: [
{id: 0},
{id: 1},
{id: 2},
{id: -1}
]
constructor: (@file, @header) ->
@numPixels = @getImageWidth() * @getImageHeight()
@numPixels *= 2 if @getImageDepth() is 16
@length = switch @getImageDepth()
when 1 then (@getImageWidth() + 7) / 8 * @getImageHeight()
when 16 then @getImageWidth() * @getImageHeight() * 2
else @getImageWidth() * @getImageHeight()
@channelLength = @length # in bytes
@length *= @getImageChannels()
@channelData = new Uint8Array(@length)
@startPos = @file.tell()
@endPos = @startPos + @length
@pixelData = []
parse: ->
@compression = @parseCompression()
# ZIP compression isn't implemented yet. Luckily this is pretty rare. Still,
# it's a TODO.
Log.debug "Image size: #{@length} (#{@getImageWidth()}x#{@getImageHeight()})"
if @compression in [2, 3]
Log.debug "ZIP compression not implemented yet, skipping."
return @file.seek @endPos, false
@parseImageData()
skip: ->
Log.debug "Skipping image data"
@file.seek @length
parseCompression: -> @file.readShortInt()
parseImageData: ->
Log.debug "Image compression: id=#{@compression}, name=#{COMPRESSIONS[@compression]}"
switch @compression
when 0 then @parseRaw()
when 1 then @parseRLE()
when 2, 3 then @parseZip()
else
Log.debug "Unknown image compression. Attempting to skip."
return @file.seek @endPos, false
@processImageData()
# Parse the image data as raw pixel values. There is no compression used here.
parseRaw: (length = @length) ->
Log.debug "Attempting to parse RAW encoded image..."
@channelData = []
@channelData.push @file.read(1)[0] for i in [0...length]
return true
# Parse the image with RLE compression. This is the same as the TIFF standard format.
# Contains the scanline byte lengths first, then the actual encoded image data.
parseRLE: ->
Log.debug "Attempting to parse RLE encoded image..."
# RLE stores the scan line byte counts in the first chunk of data
@byteCounts = @getByteCounts()
Log.debug "Read byte counts. Current pos = #{@file.tell()}, Pixels = #{@length}"
@parseChannelData()
# Get the height of the image. This varies depending on whether we're parsing layer
# channel data or not.
getImageHeight: -> @header.rows
getImageWidth: -> @header.cols
getImageChannels: -> @header.channels
getImageDepth: -> @header.depth
getByteCounts: ->
byteCounts = []
for i in [0...@getImageChannels()]
for j in [0...@getImageHeight()]
byteCounts.push @file.readShortInt()
byteCounts
parseChannelData: ->
# And then it stores the compressed image data
chanPos = 0
lineIndex = 0
for i in [0...@getImageChannels()] # i = plane num
Log.debug "Parsing channel ##{i}, Start = #{@file.tell()}"
[chanPos, lineIndex] = @decodeRLEChannel(chanPos, lineIndex)
return true
decodeRLEChannel: (chanPos, lineIndex) ->
for j in [0...@getImageHeight()]
byteCount = @byteCounts[lineIndex++]
start = @file.tell()
while @file.tell() < start + byteCount
[len] = @file.read(1)
if len < 128
len++
data = @file.read len
# memcpy!
dataIndex = 0
@channelData[k] = data[dataIndex++] for k in [chanPos...chanPos+len]
chanPos += len
else if len > 128
len ^= 0xff
len += 2
[val] = @file.read(1)
data = []
data.push val for z in [0...len]
dataIndex = 0
@channelData[k] = data[dataIndex++] for k in [chanPos...chanPos+len]
chanPos += len
[chanPos, lineIndex]
parseZip: (prediction = false) ->
#stream = inflater.append @file.read(@length)
#inflater.flush()
# ZIP decompression not implemented until I can find a PSD that's actually using it
@file.seek @endPos, false
# Once we've read the image data, we need to organize it and/or convert the pixel
# values to RGB so they're easier to work with and can be easily output to either
# browser or file.
processImageData: ->
Log.debug "Processing parsed image data. #{@channelData.length} pixels read."
switch @header.mode
when 1 # Greyscale
@combineGreyscale8Channel() if @getImageDepth() is 8
@combineGreyscale16Channel() if @getImageDepth() is 16
when 3 # RGBColor
@combineRGB8Channel() if @getImageDepth() is 8
@combineRGB16Channel() if @getImageDepth() is 16
when 4 #CMKYColor
@combineCMYK8Channel() if @getImageDepth() is 8
@combineCMYK16Channel() if @getImageDepth() is 16
when 7 # Multichannel
@combineMultiChannel8()
when 9 #LABColor
@combineLAB8Channel() if @getImageDepth() is 8
# Manually delete channel data to free up memory
delete @channelData
getAlphaValue: (alpha = 255) ->
# Layer opacity
alpha = alpha * (@layer.blendMode.opacity / 255) if @layer?
alpha
combineGreyscale8Channel: ->
if @getImageChannels() is 2
# Has alpha channel
for i in [0...@numPixels]
alpha = @channelData[i]
grey = @channelData[@channelLength + i]
@pixelData.push grey, grey, grey, @getAlphaValue(alpha)
else
for i in [0...@numPixels]
@pixelData.push @channelData[i], @channelData[i], @channelData[i], @getAlphaValue()
combineGreyscale16Channel: ->
if @getImageChannels() is 2
# Has alpha channel
for i in [0...@numPixels] by 2
alpha = Util.toUInt16 @channelData[i + 1], @channelData[i]
grey = Util.toUInt16 @channelData[@channelLength + i + 1], @channelData[@channelLength + i]
@pixelData.push grey, grey, grey, @getAlphaValue(alpha)
else
for i in [0...@numPixels] by 2
pixel = Util.toUInt16 @channelData[i+1], @channelData[i]
@pixelData.push pixel, pixel, pixel, @getAlphaValue()
combineRGB8Channel: ->
for i in [0...@numPixels]
index = 0
pixel = r: 0, g: 0, b: 0, a: 255
for chan in @channelsInfo
switch chan.id
when -1
if @getImageChannels() is 4
pixel.a = @channelData[i + (@channelLength * index)]
else continue
when 0 then pixel.r = @channelData[i + (@channelLength * index)]
when 1 then pixel.g = @channelData[i + (@channelLength * index)]
when 2 then pixel.b = @channelData[i + (@channelLength * index)]
index++
@pixelData.push pixel.r, pixel.g, pixel.b, @getAlphaValue(pixel.a)
combineRGB16Channel: ->
for i in [0...@numPixels] by 2
index = 0
pixel = r: 0, g: 0, b: 0, a: 255
for chan in @channelsInfo
b1 = @channelData[i + (@channelLength * index) + 1]
b2 = @channelData[i + (@channelLength * index)]
switch chan.id
when -1
if @getImageChannels() is 4
pixel.a = Util.toUInt16(b1, b2)
else continue
when 0 then pixel.r = Util.toUInt16(b1, b2)
when 1 then pixel.g = Util.toUInt16(b1, b2)
when 2 then pixel.b = Util.toUInt16(b1, b2)
index++
@pixelData.push pixel.r, pixel.g, pixel.b, @getAlphaValue(pixel.a)
combineCMYK8Channel: ->
for i in [0...@numPixels]
if @getImageChannels() is 5
a = @channelData[i]
c = @channelData[i + @channelLength]
m = @channelData[i + @channelLength * 2]
y = @channelData[i + @channelLength * 3]
k = @channelData[i + @channelLength * 4]
else
a = 255
c = @channelData[i]
m = @channelData[i + @channelLength]
y = @channelData[i + @channelLength * 2]
k = @channelData[i + @channelLength * 3]
rgb = PSDColor.cmykToRGB(255 - c, 255 - m, 255 - y, 255 - k)
@pixelData.push rgb.r, rgb.g, rgb.b, @getAlphaValue(a)
combineCMYK16Channel: ->
for i in [0...@numPixels] by 2
if @getImageChannels() is 5
a = @channelData[i]
c = @channelData[i + @channelLength]
m = @channelData[i + @channelLength * 2]
y = @channelData[i + @channelLength * 3]
k = @channelData[i + @channelLength * 3]
else
a = 255
c = @channelData[i]
m = @channelData[i + @channelLength]
y = @channelData[i + @channelLength * 2]
k = @channelData[i + @channelLength * 3]
rgb = PSDColor.cmykToRGB(255 - c, 255 - m, 255 - y, 255 - k)
@pixelData.push rgb.r, rgb.g, rgb.b, @getAlphaValue(a)
combineLAB8Channel: ->
for i in [0...@numPixels]
if @getImageChannels() is 4
alpha = @channelData[i]
l = @channelData[i + @channelLength]
a = @channelData[i + @channelLength * 2]
b = @channelData[i + @channelLength * 3]
else
alpha = 255
l = @channelData[i]
a = @channelData[i + @channelLength]
b = @channelData[i + @channelLength * 2]
rgb = PSDColor.labToRGB l * 100 >> 8, a - 128, b - 128
@pixelData.push rgb.r, rgb.g, rgb.b, @getAlphaValue(alpha)
combineLAB16Channel: ->
for i in [0...@numPixels] by 2
if @getImageChannels() is 4
alpha = @channelData[i]
l = @channelData[i + @channelLength]
a = @channelData[i + @channelLength * 2]
b = @channelData[i + @channelLength * 3]
else
alpha = 255
l = @channelData[i]
a = @channelData[i + @channelLength]
b = @channelData[i + @channelLength * 2]
rgb = PSDColor.labToRGB l * 100 >> 8, a - 128, b - 128
@pixelData.push rgb.r, rgb.g, rgb.b, @getAlphaValue(alpha)
combineMultiChannel8: ->
for i in [0...@numPixels]
c = @channelData[i]
m = @channelData[i + @channelLength]
y = @channelData[i + @channelLength * 2]
if @getImageChannels() is 4
k = @channelData[i + @channelLength * 3]
else
k = 255
rgb = PSDColor.cmykToRGB(255 - c, 255 - m, 255 - y, 255 - k)
@pixelData.push rgb.r, rgb.g, rgb.b, @getAlphaValue(255)
# Normally, the pixel data is stored in planar order, meaning all the red
# values come first, then the green, then the blue. In the HTML canvas, the
# pixel color values are grouped by pixel such that the values alternate
# between R, G, B, A over and over.
#
# This will return the pixels in the same format that is used by the HTML
# canvas. It is a 1D array that consists of a single pixel's color values
# expressed from 0 to 255 in chunks of 4. Each chunk consists of red,
# green, blue, and alpha values, respectively.
#
# This means a pure-red single pixel is expressed as: `[255, 0, 0, 255]`
toCanvasPixels: -> @pixelData
toFile: (filename, cb) ->
return cb() if @toCanvasPixels().length is 0
png = @getPng()
return cb() if png is null
png.encode (image) -> fs.writeFile filename, image, cb
toFileSync: (filename) ->
return if @toCanvasPixels().length is 0
png = @getPng()
return if png is null
image = png.encodeSync()
fs.writeFileSync filename, image
getPng: ->
try
{Png} = require 'png'
catch e
throw "Exporting PSDs to file requires the node-png library"
buffer = new Buffer @toCanvasPixels().length
pixelData = @toCanvasPixels()
for i in [0...pixelData.length] by 4
buffer[i] = pixelData[i]
buffer[i+1] = pixelData[i+1]
buffer[i+2] = pixelData[i+2]
buffer[i+3] = 255 - pixelData[i+3] # Why is this inverted?
try
new Png buffer, @getImageWidth(), @getImageHeight(), 'rgba'
catch e
Log.debug e
return null
toCanvas: (canvas, width = null, height = null) ->
if width is null and height is null
canvas.width = @getImageWidth()
canvas.height = @getImageHeight()
context = canvas.getContext('2d')
imageData = context.getImageData 0, 0, canvas.width, canvas.height
pixelData = imageData.data
pixelData[i] = pxl for pxl, i in @toCanvasPixels()
context.putImageData imageData, 0, 0
toImage: ->
canvas = document.createElement 'canvas'
@toCanvas canvas
canvas.toDataURL "image/png"
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