diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/rgbquant.js | 935 |
1 files changed, 0 insertions, 935 deletions
diff --git a/lib/rgbquant.js b/lib/rgbquant.js deleted file mode 100644 index 953e6f4..0000000 --- a/lib/rgbquant.js +++ /dev/null @@ -1,935 +0,0 @@ -/* -* Copyright (c) 2015, Leon Sorokin -* All rights reserved. (MIT Licensed) -* -* RgbQuant.js - an image quantization lib -*/ - -(function(){ - function RgbQuant(opts) { - opts = opts || {}; - - // 1 = by global population, 2 = subregion population threshold - this.method = opts.method || 2; - // desired final palette size - this.colors = opts.colors || 256; - // # of highest-frequency colors to start with for palette reduction - this.initColors = opts.initColors || 4096; - // color-distance threshold for initial reduction pass - this.initDist = opts.initDist || 0.01; - // subsequent passes threshold - this.distIncr = opts.distIncr || 0.005; - // palette grouping - this.hueGroups = opts.hueGroups || 10; - this.satGroups = opts.satGroups || 10; - this.lumGroups = opts.lumGroups || 10; - // if > 0, enables hues stats and min-color retention per group - this.minHueCols = opts.minHueCols || 0; - // HueStats instance - this.hueStats = this.minHueCols ? new HueStats(this.hueGroups, this.minHueCols) : null; - - // subregion partitioning box size - this.boxSize = opts.boxSize || [64,64]; - // number of same pixels required within box for histogram inclusion - this.boxPxls = opts.boxPxls || 2; - // palette locked indicator - this.palLocked = false; - // palette sort order -// this.sortPal = ['hue-','lum-','sat-']; - - // dithering/error diffusion kernel name - this.dithKern = opts.dithKern || null; - // dither serpentine pattern - this.dithSerp = opts.dithSerp || false; - // minimum color difference (0-1) needed to dither - this.dithDelta = opts.dithDelta || 0; - - // accumulated histogram - this.histogram = {}; - // palette - rgb triplets - this.idxrgb = opts.palette ? opts.palette.slice(0) : []; - // palette - int32 vals - this.idxi32 = []; - // reverse lookup {i32:idx} - this.i32idx = {}; - // {i32:rgb} - this.i32rgb = {}; - // enable color caching (also incurs overhead of cache misses and cache building) - this.useCache = opts.useCache !== false; - // min color occurance count needed to qualify for caching - this.cacheFreq = opts.cacheFreq || 10; - // allows pre-defined palettes to be re-indexed (enabling palette compacting and sorting) - this.reIndex = opts.reIndex || this.idxrgb.length == 0; - // selection of color-distance equation - this.colorDist = opts.colorDist == "manhattan" ? distManhattan : distEuclidean; - - // if pre-defined palette, build lookups - if (this.idxrgb.length > 0) { - var self = this; - this.idxrgb.forEach(function(rgb, i) { - var i32 = ( - (255 << 24) | // alpha - (rgb[2] << 16) | // blue - (rgb[1] << 8) | // green - rgb[0] // red - ) >>> 0; - - self.idxi32[i] = i32; - self.i32idx[i32] = i; - self.i32rgb[i32] = rgb; - }); - } - } - - // gathers histogram info - RgbQuant.prototype.sample = function sample(img, width) { - if (this.palLocked) - throw "Cannot sample additional images, palette already assembled."; - - var data = getImageData(img, width); - - switch (this.method) { - case 1: this.colorStats1D(data.buf32); break; - case 2: this.colorStats2D(data.buf32, data.width); break; - } - }; - - // image quantizer - // todo: memoize colors here also - // @retType: 1 - Uint8Array (default), 2 - Indexed array, 3 - Match @img type (unimplemented, todo) - RgbQuant.prototype.reduce = function reduce(img, retType, dithKern, dithSerp) { - if (!this.palLocked) - this.buildPal(); - - dithKern = dithKern || this.dithKern; - dithSerp = typeof dithSerp != "undefined" ? dithSerp : this.dithSerp; - - retType = retType || 1; - - // reduce w/dither - if (dithKern) - var out32 = this.dither(img, dithKern, dithSerp); - else { - var data = getImageData(img), - buf32 = data.buf32, - len = buf32.length, - out32 = new Uint32Array(len); - - for (var i = 0; i < len; i++) { - var i32 = buf32[i]; - out32[i] = this.nearestColor(i32); - } - } - - if (retType == 1) - return new Uint8Array(out32.buffer); - - if (retType == 2) { - var out = [], - len = out32.length; - - for (var i = 0; i < len; i++) { - var i32 = out32[i]; - out[i] = this.i32idx[i32]; - } - - return out; - } - }; - - // adapted from http://jsbin.com/iXofIji/2/edit by PAEz - RgbQuant.prototype.dither = function(img, kernel, serpentine) { - // http://www.tannerhelland.com/4660/dithering-eleven-algorithms-source-code/ - var kernels = { - FloydSteinberg: [ - [7 / 16, 1, 0], - [3 / 16, -1, 1], - [5 / 16, 0, 1], - [1 / 16, 1, 1] - ], - FalseFloydSteinberg: [ - [3 / 8, 1, 0], - [3 / 8, 0, 1], - [2 / 8, 1, 1] - ], - Stucki: [ - [8 / 42, 1, 0], - [4 / 42, 2, 0], - [2 / 42, -2, 1], - [4 / 42, -1, 1], - [8 / 42, 0, 1], - [4 / 42, 1, 1], - [2 / 42, 2, 1], - [1 / 42, -2, 2], - [2 / 42, -1, 2], - [4 / 42, 0, 2], - [2 / 42, 1, 2], - [1 / 42, 2, 2] - ], - Atkinson: [ - [1 / 8, 1, 0], - [1 / 8, 2, 0], - [1 / 8, -1, 1], - [1 / 8, 0, 1], - [1 / 8, 1, 1], - [1 / 8, 0, 2] - ], - Jarvis: [ // Jarvis, Judice, and Ninke / JJN? - [7 / 48, 1, 0], - [5 / 48, 2, 0], - [3 / 48, -2, 1], - [5 / 48, -1, 1], - [7 / 48, 0, 1], - [5 / 48, 1, 1], - [3 / 48, 2, 1], - [1 / 48, -2, 2], - [3 / 48, -1, 2], - [5 / 48, 0, 2], - [3 / 48, 1, 2], - [1 / 48, 2, 2] - ], - Burkes: [ - [8 / 32, 1, 0], - [4 / 32, 2, 0], - [2 / 32, -2, 1], - [4 / 32, -1, 1], - [8 / 32, 0, 1], - [4 / 32, 1, 1], - [2 / 32, 2, 1], - ], - Sierra: [ - [5 / 32, 1, 0], - [3 / 32, 2, 0], - [2 / 32, -2, 1], - [4 / 32, -1, 1], - [5 / 32, 0, 1], - [4 / 32, 1, 1], - [2 / 32, 2, 1], - [2 / 32, -1, 2], - [3 / 32, 0, 2], - [2 / 32, 1, 2], - ], - TwoSierra: [ - [4 / 16, 1, 0], - [3 / 16, 2, 0], - [1 / 16, -2, 1], - [2 / 16, -1, 1], - [3 / 16, 0, 1], - [2 / 16, 1, 1], - [1 / 16, 2, 1], - ], - SierraLite: [ - [2 / 4, 1, 0], - [1 / 4, -1, 1], - [1 / 4, 0, 1], - ], - }; - - if (!kernel || !kernels[kernel]) { - throw 'Unknown dithering kernel: ' + kernel; - } - - var ds = kernels[kernel]; - - var data = getImageData(img), -// buf8 = data.buf8, - buf32 = data.buf32, - width = data.width, - height = data.height, - len = buf32.length; - - var dir = serpentine ? -1 : 1; - - for (var y = 0; y < height; y++) { - if (serpentine) - dir = dir * -1; - - var lni = y * width; - - for (var x = (dir == 1 ? 0 : width - 1), xend = (dir == 1 ? width : 0); x !== xend; x += dir) { - // Image pixel - var idx = lni + x, - i32 = buf32[idx], - r1 = (i32 & 0xff), - g1 = (i32 & 0xff00) >> 8, - b1 = (i32 & 0xff0000) >> 16; - - // Reduced pixel - var i32x = this.nearestColor(i32), - r2 = (i32x & 0xff), - g2 = (i32x & 0xff00) >> 8, - b2 = (i32x & 0xff0000) >> 16; - - buf32[idx] = - (255 << 24) | // alpha - (b2 << 16) | // blue - (g2 << 8) | // green - r2; - - // dithering strength - if (this.dithDelta) { - var dist = this.colorDist([r1, g1, b1], [r2, g2, b2]); - if (dist < this.dithDelta) - continue; - } - - // Component distance - var er = r1 - r2, - eg = g1 - g2, - eb = b1 - b2; - - for (var i = (dir == 1 ? 0 : ds.length - 1), end = (dir == 1 ? ds.length : 0); i !== end; i += dir) { - var x1 = ds[i][1] * dir, - y1 = ds[i][2]; - - var lni2 = y1 * width; - - if (x1 + x >= 0 && x1 + x < width && y1 + y >= 0 && y1 + y < height) { - var d = ds[i][0]; - var idx2 = idx + (lni2 + x1); - - var r3 = (buf32[idx2] & 0xff), - g3 = (buf32[idx2] & 0xff00) >> 8, - b3 = (buf32[idx2] & 0xff0000) >> 16; - - var r4 = Math.max(0, Math.min(255, r3 + er * d)), - g4 = Math.max(0, Math.min(255, g3 + eg * d)), - b4 = Math.max(0, Math.min(255, b3 + eb * d)); - - buf32[idx2] = - (255 << 24) | // alpha - (b4 << 16) | // blue - (g4 << 8) | // green - r4; // red - } - } - } - } - - return buf32; - }; - - // reduces histogram to palette, remaps & memoizes reduced colors - RgbQuant.prototype.buildPal = function buildPal(noSort) { - if (this.palLocked || this.idxrgb.length > 0 && this.idxrgb.length <= this.colors) return; - - var histG = this.histogram, - sorted = sortedHashKeys(histG, true); - - if (sorted.length == 0) - throw "Nothing has been sampled, palette cannot be built."; - - switch (this.method) { - case 1: - var cols = this.initColors, - last = sorted[cols - 1], - freq = histG[last]; - - var idxi32 = sorted.slice(0, cols); - - // add any cut off colors with same freq as last - var pos = cols, len = sorted.length; - while (pos < len && histG[sorted[pos]] == freq) - idxi32.push(sorted[pos++]); - - // inject min huegroup colors - if (this.hueStats) - this.hueStats.inject(idxi32); - - break; - case 2: - var idxi32 = sorted; - break; - } - - // int32-ify values - idxi32 = idxi32.map(function(v){return +v;}); - - this.reducePal(idxi32); - - if (!noSort && this.reIndex) - this.sortPal(); - - // build cache of top histogram colors - if (this.useCache) - this.cacheHistogram(idxi32); - - this.palLocked = true; - }; - - RgbQuant.prototype.palette = function palette(tuples, noSort) { - this.buildPal(noSort); - return tuples ? this.idxrgb : new Uint8Array((new Uint32Array(this.idxi32)).buffer); - }; - - RgbQuant.prototype.prunePal = function prunePal(keep) { - var i32; - - for (var j = 0; j < this.idxrgb.length; j++) { - if (!keep[j]) { - i32 = this.idxi32[j]; - this.idxrgb[j] = null; - this.idxi32[j] = null; - delete this.i32idx[i32]; - } - } - - // compact - if (this.reIndex) { - var idxrgb = [], - idxi32 = [], - i32idx = {}; - - for (var j = 0, i = 0; j < this.idxrgb.length; j++) { - if (this.idxrgb[j]) { - i32 = this.idxi32[j]; - idxrgb[i] = this.idxrgb[j]; - i32idx[i32] = i; - idxi32[i] = i32; - i++; - } - } - - this.idxrgb = idxrgb; - this.idxi32 = idxi32; - this.i32idx = i32idx; - } - }; - - // reduces similar colors from an importance-sorted Uint32 rgba array - RgbQuant.prototype.reducePal = function reducePal(idxi32) { - // if pre-defined palette's length exceeds target - if (this.idxrgb.length > this.colors) { - // quantize histogram to existing palette - var len = idxi32.length, keep = {}, uniques = 0, idx, pruned = false; - - for (var i = 0; i < len; i++) { - // palette length reached, unset all remaining colors (sparse palette) - if (uniques == this.colors && !pruned) { - this.prunePal(keep); - pruned = true; - } - - idx = this.nearestIndex(idxi32[i]); - - if (uniques < this.colors && !keep[idx]) { - keep[idx] = true; - uniques++; - } - } - - if (!pruned) { - this.prunePal(keep); - pruned = true; - } - } - // reduce histogram to create initial palette - else { - // build full rgb palette - var idxrgb = idxi32.map(function(i32) { - return [ - (i32 & 0xff), - (i32 & 0xff00) >> 8, - (i32 & 0xff0000) >> 16, - ]; - }); - - var len = idxrgb.length, - palLen = len, - thold = this.initDist; - - // palette already at or below desired length - if (palLen > this.colors) { - while (palLen > this.colors) { - var memDist = []; - - // iterate palette - for (var i = 0; i < len; i++) { - var pxi = idxrgb[i], i32i = idxi32[i]; - if (!pxi) continue; - - for (var j = i + 1; j < len; j++) { - var pxj = idxrgb[j], i32j = idxi32[j]; - if (!pxj) continue; - - var dist = this.colorDist(pxi, pxj); - - if (dist < thold) { - // store index,rgb,dist - memDist.push([j, pxj, i32j, dist]); - - // kill squashed value - delete(idxrgb[j]); - palLen--; - } - } - } - - // palette reduction pass - // console.log("palette length: " + palLen); - - // if palette is still much larger than target, increment by larger initDist - thold += (palLen > this.colors * 3) ? this.initDist : this.distIncr; - } - - // if palette is over-reduced, re-add removed colors with largest distances from last round - if (palLen < this.colors) { - // sort descending - sort.call(memDist, function(a,b) { - return b[3] - a[3]; - }); - - var k = 0; - while (palLen < this.colors) { - // re-inject rgb into final palette - idxrgb[memDist[k][0]] = memDist[k][1]; - - palLen++; - k++; - } - } - } - - var len = idxrgb.length; - for (var i = 0; i < len; i++) { - if (!idxrgb[i]) continue; - - this.idxrgb.push(idxrgb[i]); - this.idxi32.push(idxi32[i]); - - this.i32idx[idxi32[i]] = this.idxi32.length - 1; - this.i32rgb[idxi32[i]] = idxrgb[i]; - } - } - }; - - // global top-population - RgbQuant.prototype.colorStats1D = function colorStats1D(buf32) { - var histG = this.histogram, - num = 0, col, - len = buf32.length; - - for (var i = 0; i < len; i++) { - col = buf32[i]; - - // skip transparent - if ((col & 0xff000000) >> 24 == 0) continue; - - // collect hue stats - if (this.hueStats) - this.hueStats.check(col); - - if (col in histG) - histG[col]++; - else - histG[col] = 1; - } - }; - - // population threshold within subregions - // FIXME: this can over-reduce (few/no colors same?), need a way to keep - // important colors that dont ever reach local thresholds (gradients?) - RgbQuant.prototype.colorStats2D = function colorStats2D(buf32, width) { - var boxW = this.boxSize[0], - boxH = this.boxSize[1], - area = boxW * boxH, - boxes = makeBoxes(width, buf32.length / width, boxW, boxH), - histG = this.histogram, - self = this; - - boxes.forEach(function(box) { - var effc = Math.max(Math.round((box.w * box.h) / area) * self.boxPxls, 2), - histL = {}, col; - - iterBox(box, width, function(i) { - col = buf32[i]; - - // skip transparent - if ((col & 0xff000000) >> 24 == 0) return; - - // collect hue stats - if (self.hueStats) - self.hueStats.check(col); - - if (col in histG) - histG[col]++; - else if (col in histL) { - if (++histL[col] >= effc) - histG[col] = histL[col]; - } - else - histL[col] = 1; - }); - }); - - if (this.hueStats) - this.hueStats.inject(histG); - }; - - // TODO: group very low lum and very high lum colors - // TODO: pass custom sort order - RgbQuant.prototype.sortPal = function sortPal() { - var self = this; - - this.idxi32.sort(function(a,b) { - var idxA = self.i32idx[a], - idxB = self.i32idx[b], - rgbA = self.idxrgb[idxA], - rgbB = self.idxrgb[idxB]; - - var hslA = rgb2hsl(rgbA[0],rgbA[1],rgbA[2]), - hslB = rgb2hsl(rgbB[0],rgbB[1],rgbB[2]); - - // sort all grays + whites together - var hueA = (rgbA[0] == rgbA[1] && rgbA[1] == rgbA[2]) ? -1 : hueGroup(hslA.h, self.hueGroups); - var hueB = (rgbB[0] == rgbB[1] && rgbB[1] == rgbB[2]) ? -1 : hueGroup(hslB.h, self.hueGroups); - - var hueDiff = hueB - hueA; - if (hueDiff) return -hueDiff; - - var lumDiff = lumGroup(+hslB.l.toFixed(2)) - lumGroup(+hslA.l.toFixed(2)); - if (lumDiff) return -lumDiff; - - var satDiff = satGroup(+hslB.s.toFixed(2)) - satGroup(+hslA.s.toFixed(2)); - if (satDiff) return -satDiff; - }); - - // sync idxrgb & i32idx - this.idxi32.forEach(function(i32, i) { - self.idxrgb[i] = self.i32rgb[i32]; - self.i32idx[i32] = i; - }); - }; - - // TOTRY: use HUSL - http://boronine.com/husl/ - RgbQuant.prototype.nearestColor = function nearestColor(i32) { - var idx = this.nearestIndex(i32); - return idx === null ? 0 : this.idxi32[idx]; - }; - - // TOTRY: use HUSL - http://boronine.com/husl/ - RgbQuant.prototype.nearestIndex = function nearestIndex(i32) { - // alpha 0 returns null index - if ((i32 & 0xff000000) >> 24 == 0) - return null; - - if (this.useCache && (""+i32) in this.i32idx) - return this.i32idx[i32]; - - var min = 1000, - idx, - rgb = [ - (i32 & 0xff), - (i32 & 0xff00) >> 8, - (i32 & 0xff0000) >> 16, - ], - len = this.idxrgb.length; - - for (var i = 0; i < len; i++) { - if (!this.idxrgb[i]) continue; // sparse palettes - - var dist = this.colorDist(rgb, this.idxrgb[i]); - - if (dist < min) { - min = dist; - idx = i; - } - } - - return idx; - }; - - RgbQuant.prototype.cacheHistogram = function cacheHistogram(idxi32) { - for (var i = 0, i32 = idxi32[i]; i < idxi32.length && this.histogram[i32] >= this.cacheFreq; i32 = idxi32[i++]) - this.i32idx[i32] = this.nearestIndex(i32); - }; - - function HueStats(numGroups, minCols) { - this.numGroups = numGroups; - this.minCols = minCols; - this.stats = {}; - - for (var i = -1; i < numGroups; i++) - this.stats[i] = {num: 0, cols: []}; - - this.groupsFull = 0; - } - - HueStats.prototype.check = function checkHue(i32) { - if (this.groupsFull == this.numGroups + 1) - this.check = function() {return;}; - - var r = (i32 & 0xff), - g = (i32 & 0xff00) >> 8, - b = (i32 & 0xff0000) >> 16, - hg = (r == g && g == b) ? -1 : hueGroup(rgb2hsl(r,g,b).h, this.numGroups), - gr = this.stats[hg], - min = this.minCols; - - gr.num++; - - if (gr.num > min) - return; - if (gr.num == min) - this.groupsFull++; - - if (gr.num <= min) - this.stats[hg].cols.push(i32); - }; - - HueStats.prototype.inject = function injectHues(histG) { - for (var i = -1; i < this.numGroups; i++) { - if (this.stats[i].num <= this.minCols) { - switch (typeOf(histG)) { - case "Array": - this.stats[i].cols.forEach(function(col){ - if (histG.indexOf(col) == -1) - histG.push(col); - }); - break; - case "Object": - this.stats[i].cols.forEach(function(col){ - if (!histG[col]) - histG[col] = 1; - else - histG[col]++; - }); - break; - } - } - } - }; - - // Rec. 709 (sRGB) luma coef - var Pr = .2126, - Pg = .7152, - Pb = .0722; - - // http://alienryderflex.com/hsp.html - function rgb2lum(r,g,b) { - return Math.sqrt( - Pr * r*r + - Pg * g*g + - Pb * b*b - ); - } - - var rd = 255, - gd = 255, - bd = 255; - - var euclMax = Math.sqrt(Pr*rd*rd + Pg*gd*gd + Pb*bd*bd); - // perceptual Euclidean color distance - function distEuclidean(rgb0, rgb1) { - var rd = rgb1[0]-rgb0[0], - gd = rgb1[1]-rgb0[1], - bd = rgb1[2]-rgb0[2]; - - return Math.sqrt(Pr*rd*rd + Pg*gd*gd + Pb*bd*bd) / euclMax; - } - - var manhMax = Pr*rd + Pg*gd + Pb*bd; - // perceptual Manhattan color distance - function distManhattan(rgb0, rgb1) { - var rd = Math.abs(rgb1[0]-rgb0[0]), - gd = Math.abs(rgb1[1]-rgb0[1]), - bd = Math.abs(rgb1[2]-rgb0[2]); - - return (Pr*rd + Pg*gd + Pb*bd) / manhMax; - } - - // http://rgb2hsl.nichabi.com/javascript-function.php - function rgb2hsl(r, g, b) { - var max, min, h, s, l, d; - r /= 255; - g /= 255; - b /= 255; - max = Math.max(r, g, b); - min = Math.min(r, g, b); - l = (max + min) / 2; - if (max == min) { - h = s = 0; - } else { - d = max - min; - s = l > 0.5 ? d / (2 - max - min) : d / (max + min); - switch (max) { - case r: h = (g - b) / d + (g < b ? 6 : 0); break; - case g: h = (b - r) / d + 2; break; - case b: h = (r - g) / d + 4; break - } - h /= 6; - } -// h = Math.floor(h * 360) -// s = Math.floor(s * 100) -// l = Math.floor(l * 100) - return { - h: h, - s: s, - l: rgb2lum(r,g,b), - }; - } - - function hueGroup(hue, segs) { - var seg = 1/segs, - haf = seg/2; - - if (hue >= 1 - haf || hue <= haf) - return 0; - - for (var i = 1; i < segs; i++) { - var mid = i*seg; - if (hue >= mid - haf && hue <= mid + haf) - return i; - } - } - - function satGroup(sat) { - return sat; - } - - function lumGroup(lum) { - return lum; - } - - function typeOf(val) { - return Object.prototype.toString.call(val).slice(8,-1); - } - - var sort = isArrSortStable() ? Array.prototype.sort : stableSort; - - // must be used via stableSort.call(arr, fn) - function stableSort(fn) { - var type = typeOf(this[0]); - - if (type == "Number" || type == "String") { - var ord = {}, len = this.length, val; - - for (var i = 0; i < len; i++) { - val = this[i]; - if (ord[val] || ord[val] === 0) continue; - ord[val] = i; - } - - return this.sort(function(a,b) { - return fn(a,b) || ord[a] - ord[b]; - }); - } - else { - var ord = this.map(function(v){return v}); - - return this.sort(function(a,b) { - return fn(a,b) || ord.indexOf(a) - ord.indexOf(b); - }); - } - } - - // test if js engine's Array#sort implementation is stable - function isArrSortStable() { - var str = "abcdefghijklmnopqrstuvwxyz"; - - return "xyzvwtursopqmnklhijfgdeabc" == str.split("").sort(function(a,b) { - return ~~(str.indexOf(b)/2.3) - ~~(str.indexOf(a)/2.3); - }).join(""); - } - - // returns uniform pixel data from various img - // TODO?: if array is passed, createimagedata, createlement canvas? take a pxlen? - function getImageData(img, width) { - var can, ctx, imgd, buf8, buf32, height; - - switch (typeOf(img)) { - case "HTMLImageElement": - can = document.createElement("canvas"); - can.width = img.naturalWidth; - can.height = img.naturalHeight; - ctx = can.getContext("2d"); - ctx.drawImage(img,0,0); - case "Canvas": - case "HTMLCanvasElement": - can = can || img; - ctx = ctx || can.getContext("2d"); - case "CanvasRenderingContext2D": - ctx = ctx || img; - can = can || ctx.canvas; - imgd = ctx.getImageData(0, 0, can.width, can.height); - case "ImageData": - imgd = imgd || img; - width = imgd.width; - if (typeOf(imgd.data) == "CanvasPixelArray") - buf8 = new Uint8Array(imgd.data); - else - buf8 = imgd.data; - case "Array": - case "CanvasPixelArray": - buf8 = buf8 || new Uint8Array(img); - case "Uint8Array": - case "Uint8ClampedArray": - buf8 = buf8 || img; - buf32 = new Uint32Array(buf8.buffer); - case "Uint32Array": - buf32 = buf32 || img; - buf8 = buf8 || new Uint8Array(buf32.buffer); - width = width || buf32.length; - height = buf32.length / width; - } - - return { - can: can, - ctx: ctx, - imgd: imgd, - buf8: buf8, - buf32: buf32, - width: width, - height: height, - }; - } - - // partitions a rect of wid x hgt into - // array of bboxes of w0 x h0 (or less) - function makeBoxes(wid, hgt, w0, h0) { - var wnum = ~~(wid/w0), wrem = wid%w0, - hnum = ~~(hgt/h0), hrem = hgt%h0, - xend = wid-wrem, yend = hgt-hrem; - - var bxs = []; - for (var y = 0; y < hgt; y += h0) - for (var x = 0; x < wid; x += w0) - bxs.push({x:x, y:y, w:(x==xend?wrem:w0), h:(y==yend?hrem:h0)}); - - return bxs; - } - - // iterates @bbox within a parent rect of width @wid; calls @fn, passing index within parent - function iterBox(bbox, wid, fn) { - var b = bbox, - i0 = b.y * wid + b.x, - i1 = (b.y + b.h - 1) * wid + (b.x + b.w - 1), - cnt = 0, incr = wid - b.w + 1, i = i0; - - do { - fn.call(this, i); - i += (++cnt % b.w == 0) ? incr : 1; - } while (i <= i1); - } - - // returns array of hash keys sorted by their values - function sortedHashKeys(obj, desc) { - var keys = []; - - for (var key in obj) - keys.push(key); - - return sort.call(keys, function(a,b) { - return desc ? obj[b] - obj[a] : obj[a] - obj[b]; - }); - } - - // expose - this.RgbQuant = RgbQuant; - - // expose to commonJS - if (typeof module !== 'undefined' && module.exports) { - module.exports = RgbQuant; - } - -}).call(this); |