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Kernel = function (w, h, a) {
this.w = w
this.h = h
this.a = a
}
Kernel.prototype.normalize = function(){
var n = 0;
for (var i = 0; i < this.a.length; i++)
n += this.a[i];
for (var i = 0; i < this.a.length; i++)
this.a[i] /= n;
return this
}
ConvolveOp = function (kernel, edge_zero_fill, idk) {
var k = kernel.a
var klen = k.length
var kw = kernel.w
var kh = kernel.h
var kx = -((kw / 2)|0)
var ky = -((kh / 2)|0)
this.filter = function(srcImageData, destImageData){
// assume these are both identically sized canvas objects..
var src = srcImageData.data
var dest = destImageData.data
var w = srcImageData.width
var h = srcImageData.height
var ix, iy, it, jx, jy, jt
var r, g, b, a
for (var i = 0, len = w*h; i < len; i++) {
ix = i%w
iy = (i/w)|0
it = i * 4
r = g = b = a = 0
for (var j = 0; j < klen; j++) {
jx = ix + j%kw + kx
jy = iy + ((j/kh)|0) + ky
jt = 4 * (jx + jy*w)
if (0 > jx || jx > w || 0 > jy || jy > h) {
if (edge_zero_fill) {
continue
}
jt = it
}
r += src[jt] * k[j]
g += src[jt+1] * k[j]
b += src[jt+2] * k[j]
a += src[jt+3] * k[j]
}
dest[it] = r
dest[it+1] = g
dest[it+2] = b
dest[it+3] = a
}
return destImageData
}
this.convolveCanvas = function(image){
var target = document.createElement("canvas")
var w = target.width = image.width
var h = target.height = image.height
var imagectx = image.getContext('2d')
var targetctx = target.getContext('2d')
targetctx.drawImage(image, 0, 0);
// get source pixels
var src = imagectx.getImageData(0,0,w,h)
var dest = targetctx.getImageData(0,0,w,h)
// convolve the cloned image
dest = this.filter(src, dest);
targetctx.putImageData(dest, 0,0)
return target
}
}
ConvolveOp.prototype.EDGE_NO_OP = 0
ConvolveOp.prototype.EDGE_ZERO_FILL = 1
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