3 function dePalette(indata, outdata, width, height, palette) {
5 // use values from palette
6 for (var y = 0; y < height; y++) {
7 for (var x = 0; x < width; x++) {
8 var color = palette[indata[pxPos]];
11 throw new Error('index ' + indata[pxPos] + ' not in palette');
14 for (var i = 0; i < 4; i++) {
15 outdata[pxPos + i] = color[i];
22 function replaceTransparentColor(indata, outdata, width, height, transColor) {
24 for (var y = 0; y < height; y++) {
25 for (var x = 0; x < width; x++) {
26 var makeTrans = false;
28 if (transColor.length === 1) {
29 if (transColor[0] === indata[pxPos]) {
33 else if (transColor[0] === indata[pxPos] && transColor[1] === indata[pxPos + 1] && transColor[2] === indata[pxPos + 2]) {
37 for (var i = 0; i < 4; i++) {
38 outdata[pxPos + i] = 0;
46 function scaleDepth(indata, outdata, width, height, depth) {
47 var maxOutSample = 255;
48 var maxInSample = Math.pow(2, depth) - 1;
51 for (var y = 0; y < height; y++) {
52 for (var x = 0; x < width; x++) {
53 for (var i = 0; i < 4; i++) {
54 outdata[pxPos + i] = Math.floor((indata[pxPos + i] * maxOutSample) / maxInSample + 0.5);
61 module.exports = function(indata, imageData) {
63 var depth = imageData.depth;
64 var width = imageData.width;
65 var height = imageData.height;
66 var colorType = imageData.colorType;
67 var transColor = imageData.transColor;
68 var palette = imageData.palette;
70 var outdata = indata; // only different for 16 bits
72 if (colorType === 3) { // paletted
73 dePalette(indata, outdata, width, height, palette);
77 replaceTransparentColor(indata, outdata, width, height, transColor);
79 // if it needs scaling
81 // if we need to change the buffer size
83 outdata = new Buffer(width * height * 4);
85 scaleDepth(indata, outdata, width, height, depth);