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v2.3 - updated image data split for multicore function.
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@viliusle
viliusle committed Dec 27, 2016
1 parent 321cabb commit 1126997
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3 changes: 2 additions & 1 deletion dist/hermite.js
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119 changes: 56 additions & 63 deletions src/hermite.js
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@

/**
/*
* Hermite resize - fast image resize/resample using Hermite filter.
* Version: 2.2
* Author: ViliusL
* demo: http://viliusle.github.io/miniPaint/
*/
Expand Down Expand Up @@ -114,7 +114,7 @@ function Hermite_class() {
var height_source = canvas.height;
width = Math.round(width);
height = Math.round(height);
var ratio_h_half = Math.ceil(height_source / height / 2);
var ratio_h = height_source / height;

//stop old workers
if (workers_archive.length > 0) {
Expand All @@ -129,32 +129,30 @@ function Hermite_class() {
var ctx = canvas.getContext("2d");

//prepare source and target data for workers
var source = new Array(cores);
var target = new Array(cores);
var data_part = [];
var block_height = Math.ceil(height_source / cores / 2) * 2;
var end_y = -1;
for (var c = 0; c < cores; c++) {
//source
var offset_y = Math.ceil(height_source / cores) * c;
var block_height = Math.ceil(height_source / cores) + ratio_h_half * cores;
if (offset_y + block_height > height_source) {
block_height = height_source - offset_y;
}
if (block_height < 1) {
//source
var offset_y = end_y + 1;
if (offset_y > height_source) {
//size too small, nothing left for this core
continue;
}
source[c] = ctx.getImageData(0, offset_y, width_source, block_height);

end_y = offset_y + block_height - 1;
end_y = Math.min(end_y, height_source - 1);

var current_block_height = block_height;
current_block_height = Math.min(block_height, height_source - offset_y);

//target
offset_y = Math.ceil(height / cores) * c;
block_height = Math.ceil(height / cores);
if (offset_y + block_height > height) {
block_height = height - offset_y;
}
if (block_height < 1) {
//size too small, nothing left for this core
continue;
}
target[c] = true;
//console.log('source split: ', '#'+c, offset_y, end_y, 'height: '+current_block_height);

data_part[c] = {};
data_part[c].source = ctx.getImageData(0, offset_y, width_source, block_height);
data_part[c].target = true;
data_part[c].start_y = Math.ceil(offset_y / ratio_h);
data_part[c].height = current_block_height;
}

//clear and resize canvas
Expand All @@ -168,7 +166,7 @@ function Hermite_class() {
//start
var workers_in_use = 0;
for (var c = 0; c < cores; c++) {
if (target[c] == undefined) {
if (data_part[c].target == undefined) {
//no job for this worker
continue;
}
Expand All @@ -183,25 +181,23 @@ function Hermite_class() {
delete workers_archive[core];

//draw
target[core] = ctx.createImageData(width, Math.ceil(height / cores));
target[core].data.set(event.data.target);
var y = Math.ceil(height / cores) * core;
ctx.putImageData(target[core], 0, y);

var height_part = Math.ceil(data_part[core].height / ratio_h);
data_part[core].target = ctx.createImageData(width, height_part);
data_part[core].target.data.set(event.data.target);
ctx.putImageData(data_part[core].target, 0, data_part[core].start_y);
if (workers_in_use <= 0) {
//finish
on_finish();
}
};

var objData = {
width_source: width_source,
height_source: height_source,
height_source: data_part[c].height,
width: width,
height: height,
height: Math.ceil(data_part[c].height / ratio_h),
core: c,
cores: cores,
source: source[c].data.buffer,
source: data_part[c].source.data.buffer,
};
my_worker.postMessage(objData, [objData.source]);
}
Expand All @@ -213,30 +209,23 @@ function Hermite_class() {
//begin worker
onmessage = function (event) {
var core = event.data.core;
var cores = event.data.cores;
var width_source = event.data.width_source;
var height_source = event.data.height_source;
var width = event.data.width;
var height = event.data.height;

var ratio_w = width_source / width;
var ratio_h = height_source / height;
var ratio_w_half = Math.ceil(ratio_w / 2);
var ratio_h_half = Math.ceil(ratio_h / 2);

var source = new Uint8ClampedArray(event.data.source);
var source_h = source.length / width_source / 4;

var target_size = width * Math.ceil(height / cores) * 4;
var target_size = width * height * 4;
var target_memory = new ArrayBuffer(target_size);
var target = new Uint8ClampedArray(target_memory, 0, target_size);

//j position in original source = j + d_h - d_h_source;
var d_h_source = Math.ceil(height_source / cores) * core;
var d_h = Math.ceil(height / cores) * core;

//calculate
for (var j = 0; j < Math.ceil(height / cores); j++) {
for (var j = 0; j < height; j++) {
for (var i = 0; i < width; i++) {
var x2 = (i + j * width) * 4;
var weight = 0;
Expand All @@ -246,22 +235,22 @@ function Hermite_class() {
var gx_g = 0;
var gx_b = 0;
var gx_a = 0;
var center_y = (d_h + j + 0.5) * ratio_h - d_h_source;

var yy_start = Math.floor(j * ratio_h);
var yy_stop = Math.ceil((d_h + j + 1) * ratio_h - d_h_source);
var center_y = j * ratio_h;

var xx_start = Math.floor(i * ratio_w);
var xx_stop = Math.ceil((i + 1) * ratio_w);
var yy_start = Math.floor(j * ratio_h);
var yy_stop = Math.ceil((j + 1) * ratio_h);

xx_stop = Math.min(xx_stop, width_source);
yy_stop = Math.min(yy_stop, height_source);

for (var yy = yy_start; yy < yy_stop; yy++) {
if (yy >= source_h || yy < 0) {
//extra border check
continue;
}
var dy = Math.abs(center_y - (yy + 0.5)) / ratio_h_half;
var center_x = (i + 0.5) * ratio_w;
var dy = Math.abs(center_y - yy) / ratio_h_half;
var center_x = i * ratio_w;
var w0 = dy * dy; //pre-calc part of w
for (var xx = xx_start; xx < xx_stop; xx++) {
var dx = Math.abs(center_x - (xx + 0.5)) / ratio_w_half;
var dx = Math.abs(center_x - xx) / ratio_w_half;
var w = Math.sqrt(w0 + dx * dx);
if (w >= 1) {
//pixel too far
Expand Down Expand Up @@ -336,17 +325,21 @@ function Hermite_class() {
var gx_g = 0;
var gx_b = 0;
var gx_a = 0;
var center_y = (j + 0.5) * ratio_h;
var center_y = j * ratio_h;

var xx_start = Math.floor(i * ratio_w);
var xx_stop = Math.ceil((i + 1) * ratio_w);
var yy_start = Math.floor(j * ratio_h);
var yy_stop = Math.ceil((j + 1) * ratio_h);
xx_stop = Math.min(xx_stop, width_source);
yy_stop = Math.min(yy_stop, height_source);

for (var yy = yy_start; yy < yy_stop; yy++) {
var dy = Math.abs(center_y - (yy + 0.5)) / ratio_h_half;
var center_x = (i + 0.5) * ratio_w;
var dy = Math.abs(center_y - yy) / ratio_h_half;
var center_x = i * ratio_w;
var w0 = dy * dy; //pre-calc part of w
var xx_start = Math.floor(i * ratio_w);
var xx_stop = Math.ceil((i + 1) * ratio_w);
for (var xx = xx_start; xx < xx_stop; xx++) {
var dx = Math.abs(center_x - (xx + 0.5)) / ratio_w_half;
var dx = Math.abs(center_x - xx) / ratio_w_half;
var w = Math.sqrt(w0 + dx * dx);
if (w >= 1) {
//pixel too far
Expand Down

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