MIT License

Demo: phoboslab.org/log/2013/11/webgl-image-filter

Construct a chain of image filters and apply them to an Image or Canvas element. All filters are executed by WebGL Shaders which makes them pretty fast.

Please also have a look at the excellent glfx.js by @evanw.

// Synopsis: create the filter object, add filters to it and apply
// it to an image

// Example:
try {
	var filter = new WebGLImageFilter();
}
catch( err ) {
	// Handle browsers that don't support WebGL
}

filter.addFilter('hue', 180);
filter.addFilter('negative');
filter.addFilter('blur', 7);
var filteredImage = filter.apply(inputImage);

// The 'filteredImage' is a canvas element. You can draw it on a 2D canvas
// or just add it to your DOM

// Use .reset() to clear the current filter chain. This is faster than creating a new
// WebGLImageFilter instance
filter.reset();

• colorMatrix( matrix ) apply a the 5x5 color matrix (Array[20]), similar to Flash's ColorMatrixFilter
• convolution( matrix ) apply a 3x3 convolution matrix (Array[9])
• blur( size ) blur with size in pixels

• brightness( amount ) change brightness. 1 increases the it two fold, -1 halfes it
• saturation( amount ) change saturation. 1 increases the it two fold, -1 halfes it
• contrast( amount ) change contrast. 1 increases the it two fold, -1 halfes it
• negative() invert colors
• hue( rotation ) rotate the hue, values are 0-360
• desaturate() desaturate the image by all channels equally
• desaturateLuminance() desaturate the image taking the natural luminace of each channel into acocunt
• sepia() sepia colors
• brownie() vintage colors
• vintagePinhole() vintage colors
• kodachrome() vintage colors
• technicolor() vintage colors
• detectEdges() detect edges
• sobelX() detect edges using a horizontal sobel operator
• sobelY() detect edges using a vertical sobel operator
• sharpen( amount ) sharpen
• emboss( size ) emboss effect with size in pixels
• polaroid() polaroid camera effect
• shiftToBGR() shift colors from RGB to BGR