mirror of
https://github.com/konvajs/konva.git
synced 2026-01-18 11:41:20 +08:00
75d0b8fe04
I added the experimental folder to show some work on filters that
can be applied to an entire layer. Multiple filters can be applied
to a layer (in any order, multiple times). To hook into the layer I
use:
layer.on('draw', filterFunc);
Eventually, I would like to move that to `layer.filterFunc` and
automatically apply it after the draw. `filterFunc` looks like:
function filterFunc(){
// Get pixel data and create a temporary pixel buffer for working
var imageData = this.getContext().getImageData(0,0,this.getCanvas().width,this.getCanvas().height);
var scratchData = this.getContext().createImageData(imageData);
// Apply all filters here
ColorStretch(imageData,scratchData,{});
// Copy the pixel data back
this.getContext().putImageData(scratchData,0,0);
}
`ColorStretch` is an example of a filter. It takes 3 arguments: the
original image data, image data to write the result to, and an options
object.
17 lines
409 B
JavaScript
17 lines
409 B
JavaScript
Threshold = (function () {
|
|
var Threshold = function (src, dst, opt) {
|
|
var level = opt.level || 128;
|
|
var srcPixels = src.data,
|
|
dstPixels = dst.data,
|
|
nPixels = srcPixels.length,
|
|
i;
|
|
for (i = 0; i < nPixels; i += 1) {
|
|
if (srcPixels[i] < level) {
|
|
dstPixels[i] = 0;
|
|
} else {
|
|
dstPixels[i] = 255;
|
|
}
|
|
}
|
|
};
|
|
return Threshold;
|
|
})(); |