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Merge pull request #794 from brendandahl/devicen

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DeviceN Colorspace and Multidimensional Sampling Function Support
This commit is contained in:
notmasteryet 2011-11-22 09:42:53 -08:00
commit 2829e8016a
5 changed files with 140 additions and 70 deletions
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59
src/colorspace.js
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@ -24,7 +24,7 @@ var ColorSpace = (function colorSpaceColorSpace() {
constructor.parse = function colorSpaceParse(cs, xref, res) {
var IR = constructor.parseToIR(cs, xref, res);
if (IR instanceof SeparationCS)
if (IR instanceof AlternateCS)
return IR;
return constructor.fromIR(IR);
@ -50,11 +50,12 @@ var ColorSpace = (function colorSpaceColorSpace() {
var hiVal = IR[2];
var lookup = IR[3];
return new IndexedCS(ColorSpace.fromIR(baseIndexedCS), hiVal, lookup);
case 'SeparationCS':
var alt = IR[1];
var tintFnIR = IR[2];
case 'AlternateCS':
var numComps = IR[1];
var alt = IR[2];
var tintFnIR = IR[3];
return new SeparationCS(ColorSpace.fromIR(alt),
return new AlternateCS(numComps, ColorSpace.fromIR(alt),
PDFFunction.fromIR(tintFnIR));
default:
error('Unkown name ' + name);
@ -134,11 +135,17 @@ var ColorSpace = (function colorSpaceColorSpace() {
var lookup = xref.fetchIfRef(cs[3]);
return ['IndexedCS', baseIndexedCS, hiVal, lookup];
case 'Separation':
case 'DeviceN':
var name = cs[1];
var numComps = 1;
if (isName(name))
numComps = 1;
else if (isArray(name))
numComps = name.length;
var alt = ColorSpace.parseToIR(cs[2], xref, res);
var tintFnIR = PDFFunction.getIR(xref, xref.fetchIfRef(cs[3]));
return ['SeparationCS', alt, tintFnIR];
return ['AlternateCS', numComps, alt, tintFnIR];
case 'Lab':
case 'DeviceN':
default:
error('unimplemented color space object "' + mode + '"');
}
@ -151,33 +158,45 @@ var ColorSpace = (function colorSpaceColorSpace() {
return constructor;
})();
var SeparationCS = (function separationCS() {
function constructor(base, tintFn) {
this.name = 'Separation';
this.numComps = 1;
this.defaultColor = [1];
/**
* Alternate color space handles both Separation and DeviceN color spaces. A
* Separation color space is actually just a DeviceN with one color component.
* Both color spaces use a tinting function to convert colors to a base color
* space.
*/
var AlternateCS = (function alternateCS() {
function constructor(numComps, base, tintFn) {
this.name = 'Alternate';
this.numComps = numComps;
this.defaultColor = [];
for (var i = 0; i < numComps; ++i)
this.defaultColor.push(1);
this.base = base;
this.tintFn = tintFn;
}
constructor.prototype = {
getRgb: function sepcs_getRgb(color) {
getRgb: function altcs_getRgb(color) {
var tinted = this.tintFn(color);
return this.base.getRgb(tinted);
},
getRgbBuffer: function sepcs_getRgbBuffer(input, bits) {
getRgbBuffer: function altcs_getRgbBuffer(input, bits) {
var tintFn = this.tintFn;
var base = this.base;
var scale = 1 / ((1 << bits) - 1);
var length = input.length;
var pos = 0;
var numComps = base.numComps;
var baseBuf = new Uint8Array(numComps * length);
var baseNumComps = base.numComps;
var baseBuf = new Uint8Array(baseNumComps * length);
var numComps = this.numComps;
var scaled = new Array(numComps);
for (var i = 0; i < length; ++i) {
var scaled = input[i] * scale;
var tinted = tintFn([scaled]);
for (var j = 0; j < numComps; ++j)
for (var i = 0; i < length; i += numComps) {
for (var z = 0; z < numComps; ++z)
scaled[z] = input[i + z] * scale;
var tinted = tintFn(scaled);
for (var j = 0; j < baseNumComps; ++j)
baseBuf[pos++] = 255 * tinted[j];
}
return base.getRgbBuffer(baseBuf, 8);

143
src/function.js
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@ -20,6 +20,8 @@ var PDFFunction = (function pdfFunction() {
var array = [];
var codeSize = 0;
var codeBuf = 0;
// 32 is a valid bps so shifting won't work
var sampleMul = 1.0 / (Math.pow(2.0, bps) - 1);
var strBytes = str.getBytes((length * bps + 7) / 8);
var strIdx = 0;
@ -30,7 +32,7 @@ var PDFFunction = (function pdfFunction() {
codeSize += 8;
}
codeSize -= bps;
array.push(codeBuf >> codeSize);
array.push((codeBuf >> codeSize) * sampleMul);
codeBuf &= (1 << codeSize) - 1;
}
return array;
@ -76,6 +78,17 @@ var PDFFunction = (function pdfFunction() {
},
constructSampled: function pdfFunctionConstructSampled(str, dict) {
function toMultiArray(arr) {
var inputLength = arr.length;
var outputLength = arr.length / 2;
var out = new Array(outputLength);
var index = 0;
for (var i = 0; i < inputLength; i += 2) {
out[index] = [arr[i], arr[i + 1]];
++index;
}
return out;
}
var domain = dict.get('Domain');
var range = dict.get('Range');
@ -85,9 +98,8 @@ var PDFFunction = (function pdfFunction() {
var inputSize = domain.length / 2;
var outputSize = range.length / 2;
if (inputSize != 1)
error('No support for multi-variable inputs to functions: ' +
inputSize);
domain = toMultiArray(domain);
range = toMultiArray(range);
var size = dict.get('Size');
var bps = dict.get('BitsPerSample');
@ -105,15 +117,36 @@ var PDFFunction = (function pdfFunction() {
encode.push(size[i] - 1);
}
}
encode = toMultiArray(encode);
var decode = dict.get('Decode');
if (!decode)
decode = range;
else
decode = toMultiArray(decode);
// Precalc the multipliers
var inputMul = new Float64Array(inputSize);
for (var i = 0; i < inputSize; ++i) {
inputMul[i] = (encode[i][1] - encode[i][0]) /
(domain[i][1] - domain[i][0]);
}
var idxMul = new Int32Array(inputSize);
idxMul[0] = outputSize;
for (i = 1; i < inputSize; ++i) {
idxMul[i] = idxMul[i - 1] * size[i - 1];
}
var nSamples = outputSize;
for (i = 0; i < inputSize; ++i)
nSamples *= size[i];
var samples = this.getSampleArray(size, outputSize, bps, str);
return [
CONSTRUCT_SAMPLED, inputSize, domain, encode, decode, samples, size,
outputSize, bps, range
outputSize, bps, range, inputMul, idxMul, nSamples
];
},
@ -127,64 +160,74 @@ var PDFFunction = (function pdfFunction() {
var outputSize = IR[7];
var bps = IR[8];
var range = IR[9];
var inputMul = IR[10];
var idxMul = IR[11];
var nSamples = IR[12];
return function constructSampledFromIRResult(args) {
var clip = function constructSampledFromIRClip(v, min, max) {
if (v > max)
v = max;
else if (v < min)
v = min;
return v;
};
if (inputSize != args.length)
error('Incorrect number of arguments: ' + inputSize + ' != ' +
args.length);
// Most of the below is a port of Poppler's implementation.
// TODO: There's a few other ways to do multilinear interpolation such
// as piecewise, which is much faster but an approximation.
var out = new Float64Array(outputSize);
var x;
var e = new Array(inputSize);
var efrac0 = new Float64Array(inputSize);
var efrac1 = new Float64Array(inputSize);
var sBuf = new Float64Array(1 << inputSize);
var i, j, k, idx, t;
for (var i = 0; i < inputSize; i++) {
var i2 = i * 2;
// clip to the domain
var v = clip(args[i], domain[i2], domain[i2 + 1]);
// encode
v = encode[i2] + ((v - domain[i2]) *
(encode[i2 + 1] - encode[i2]) /
(domain[i2 + 1] - domain[i2]));
// clip to the size
args[i] = clip(v, 0, size[i] - 1);
// map input values into sample array
for (i = 0; i < inputSize; ++i) {
x = (args[i] - domain[i][0]) * inputMul[i] + encode[i][0];
if (x < 0) {
x = 0;
} else if (x > size[i] - 1) {
x = size[i] - 1;
}
e[i] = [Math.floor(x), 0];
if ((e[i][1] = e[i][0] + 1) >= size[i]) {
// this happens if in[i] = domain[i][1]
e[i][1] = e[i][0];
}
efrac1[i] = x - e[i][0];
efrac0[i] = 1 - efrac1[i];
}
// interpolate to table
TODO('Multi-dimensional interpolation');
var floor = Math.floor(args[0]);
var ceil = Math.ceil(args[0]);
var scale = args[0] - floor;
// for each output, do m-linear interpolation
for (i = 0; i < outputSize; ++i) {
floor *= outputSize;
ceil *= outputSize;
var output = [], v = 0;
for (var i = 0; i < outputSize; ++i) {
if (ceil == floor) {
v = samples[ceil + i];
} else {
var low = samples[floor + i];
var high = samples[ceil + i];
v = low * scale + high * (1 - scale);
// pull 2^m values out of the sample array
for (j = 0; j < (1 << inputSize); ++j) {
idx = i;
for (k = 0, t = j; k < inputSize; ++k, t >>= 1) {
idx += idxMul[k] * (e[k][t & 1]);
}
if (idx >= 0 && idx < nSamples) {
sBuf[j] = samples[idx];
} else {
sBuf[j] = 0; // TODO Investigate if this is what Adobe does
}
}
var i2 = i * 2;
// decode
v = decode[i2] + (v * (decode[i2 + 1] - decode[i2]) /
((1 << bps) - 1));
// do m sets of interpolations
for (j = 0, t = (1 << inputSize); j < inputSize; ++j, t >>= 1) {
for (k = 0; k < t; k += 2) {
sBuf[k >> 1] = efrac0[j] * sBuf[k] + efrac1[j] * sBuf[k + 1];
}
}
// clip to the domain
output.push(clip(v, range[i2], range[i2 + 1]));
// map output value to range
out[i] = (sBuf[0] * (decode[i][1] - decode[i][0]) + decode[i][0]);
if (out[i] < range[i][0]) {
out[i] = range[i][0];
} else if (out[i] > range[i][1]) {
out[i] = range[i][1];
}
}
return output;
return out;
}
},

1
test/pdfs/.gitignore vendored
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@ -14,4 +14,5 @@
!sizes.pdf
!close-path-bug.pdf
!alphatrans.pdf
!devicen.pdf

BIN
test/pdfs/devicen.pdf Normal file
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Binary file not shown.

7
test/test_manifest.json
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@ -268,5 +268,12 @@
"link": false,
"rounds": 1,
"type": "eq"
},
{ "id": "devicen",
"file": "pdfs/devicen.pdf",
"md5": "aac6a91725435d1376c6ff492dc5cb75",
"link": false,
"rounds": 1,
"type": "eq"
}
]