Innovenergy_trunk/frontend/node_modules/pngjs/lib/format-normaliser.js

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'use strict';
function dePalette(indata, outdata, width, height, palette) {
var pxPos = 0;
// use values from palette
for (var y = 0; y < height; y++) {
for (var x = 0; x < width; x++) {
var color = palette[indata[pxPos]];
if (!color) {
throw new Error('index ' + indata[pxPos] + ' not in palette');
}
for (var i = 0; i < 4; i++) {
outdata[pxPos + i] = color[i];
}
pxPos += 4;
}
}
}
function replaceTransparentColor(indata, outdata, width, height, transColor) {
var pxPos = 0;
for (var y = 0; y < height; y++) {
for (var x = 0; x < width; x++) {
var makeTrans = false;
if (transColor.length === 1) {
if (transColor[0] === indata[pxPos]) {
makeTrans = true;
}
}
else if (transColor[0] === indata[pxPos] && transColor[1] === indata[pxPos + 1] && transColor[2] === indata[pxPos + 2]) {
makeTrans = true;
}
if (makeTrans) {
for (var i = 0; i < 4; i++) {
outdata[pxPos + i] = 0;
}
}
pxPos += 4;
}
}
}
function scaleDepth(indata, outdata, width, height, depth) {
var maxOutSample = 255;
var maxInSample = Math.pow(2, depth) - 1;
var pxPos = 0;
for (var y = 0; y < height; y++) {
for (var x = 0; x < width; x++) {
for (var i = 0; i < 4; i++) {
outdata[pxPos + i] = Math.floor((indata[pxPos + i] * maxOutSample) / maxInSample + 0.5);
}
pxPos += 4;
}
}
}
module.exports = function(indata, imageData) {
var depth = imageData.depth;
var width = imageData.width;
var height = imageData.height;
var colorType = imageData.colorType;
var transColor = imageData.transColor;
var palette = imageData.palette;
var outdata = indata; // only different for 16 bits
if (colorType === 3) { // paletted
dePalette(indata, outdata, width, height, palette);
}
else {
if (transColor) {
replaceTransparentColor(indata, outdata, width, height, transColor);
}
// if it needs scaling
if (depth !== 8) {
// if we need to change the buffer size
if (depth === 16) {
outdata = new Buffer(width * height * 4);
}
scaleDepth(indata, outdata, width, height, depth);
}
}
return outdata;
};