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[WIP] Optimize ImageData creation 

This commit changes several places which use `createImageData` over
to using the `ImageData(data, width, height)` constructor form.  This
allows us to use a statically allocated ArrayBuffer to be the underlying
storage for the image data, so we only have to create a small
Uint8ClmapedArray "pointer", instead of having to create underlying
storage each time.
This commit is contained in:
Solly Ross 2015-12-22 15:21:42 -05:00
parent f2cd54b160
commit 8eedab379f
1 changed files with 6 additions and 2 deletions
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8
include/display.js
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@ -32,6 +32,7 @@ var Display;
// the full frame buffer (logical canvas) size // the full frame buffer (logical canvas) size
this._fb_width = 0; this._fb_width = 0;
this._fb_height = 0; this._fb_height = 0;
this._fb_cache = null;
// the size limit of the viewport (start disabled) // the size limit of the viewport (start disabled)
this._maxWidth = 0; this._maxWidth = 0;
@ -335,6 +336,7 @@ var Display;
this._fb_width = width; this._fb_width = width;
this._fb_height = height; this._fb_height = height;
this._fb_cache = new ArrayBuffer(width * height * 4);
this._rescale(this._scale); this._rescale(this._scale);
@ -678,7 +680,8 @@ var Display;
}, },
_rgbImageData: function (x, y, vx, vy, width, height, arr, offset) { _rgbImageData: function (x, y, vx, vy, width, height, arr, offset) {
var img = this._drawCtx.createImageData(width, height); //var img = this._drawCtx.createImageData(width, height);
var img = new ImageData(new Uint8ClampedArray(this._fb_cache, 0, width * height * 4), width, height);
var data = img.data; var data = img.data;
for (var i = 0, j = offset; i < width * height * 4; i += 4, j += 3) { for (var i = 0, j = offset; i < width * height * 4; i += 4, j += 3) {
data[i] = arr[j]; data[i] = arr[j];
@ -690,7 +693,8 @@ var Display;
}, },
_bgrxImageData: function (x, y, vx, vy, width, height, arr, offset) { _bgrxImageData: function (x, y, vx, vy, width, height, arr, offset) {
var img = this._drawCtx.createImageData(width, height); //var img = this._drawCtx.createImageData(width, height);
var img = new ImageData(new Uint8ClampedArray(this._fb_cache, 0, width * height * 4), width, height);
var data = img.data; var data = img.data;
for (var i = 0, j = offset; i < width * height * 4; i += 4, j += 4) { for (var i = 0, j = offset; i < width * height * 4; i += 4, j += 4) {
data[i] = arr[j + 2]; data[i] = arr[j + 2];