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Tweaked jpeg-js library encoder to allow for RGB image data (rather than... #2

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Tweaked jpeg-js library encoder to allow for RGB image data (rather than... #2

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Tweaked jpeg-js library encoder to allow for RGB image data (rather t…
emma-floored Jun 30, 2014
e0870d6
Missed a few changes when I copied this over yesterday
emma-floored Jul 1, 2014
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34 changes: 17 additions & 17 deletions lib/encoder.js
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Original file line number Diff line number Diff line change
Expand Up @@ -585,7 +585,7 @@ function JPEGEncoder(quality) {
}
}

this.encode = function(image,quality) // image data object
this.encode = function(image,quality,channels) // image data object
{
var time_start = new Date().getTime();

Expand Down Expand Up @@ -620,36 +620,35 @@ function JPEGEncoder(quality) {
var width = image.width;
var height = image.height;

var quadWidth = width*4;
var tripleWidth = width*3;
var channelWidth = width*channels;

var x, y = 0;
var r, g, b;
var start,p, col,row,pos;
while(y < height){
x = 0;
while(x < quadWidth){
start = quadWidth * y + x;
while(x < channelWidth){
start = channelWidth * y + x;
p = start;
col = -1;
row = 0;

for(pos=0; pos < 64; pos++){
row = pos >> 3;// /8
col = ( pos & 7 ) * 4; // %8
p = start + ( row * quadWidth ) + col;
col = ( pos & 7 ) * channels; // %8
p = start + ( row * channelWidth ) + col;

if(y+row >= height){ // padding bottom
p-= (quadWidth*(y+1+row-height));
p-= (channelWidth*(y+1+row-height));
}

if(x+col >= quadWidth){ // padding right
p-= ((x+col) - quadWidth +4)
if(x+col >= channelWidth){ // padding right
p-= ((x+col) - channelWidth + channels)
}

r = imageData[ p++ ];
g = imageData[ p++ ];
b = imageData[ p++ ];
r = imageData[ p ];
g = imageData[ p+1 ];
b = imageData[ p+2 ];


/* // calculate YUV values dynamically
Expand All @@ -668,9 +667,9 @@ function JPEGEncoder(quality) {
DCY = processDU(YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
DCU = processDU(UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
DCV = processDU(VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
x+=32;
x += 8 * channels;
}
y+=8;
y += 8;
}


Expand Down Expand Up @@ -742,10 +741,11 @@ function JPEGEncoder(quality) {
};
module.exports = encode;

function encode(imgData, qu) {
function encode(imgData, qu, channels) {
if (typeof qu === 'undefined') qu = 50;
if (typeof channels === 'undefined') channels = 3;
var encoder = new JPEGEncoder(qu);
var data = encoder.encode(imgData, qu);
var data = encoder.encode(imgData, qu, channels);
return {
data: data,
width: imgData.width,
Expand Down