Contrast Module should use changePixel Method

[harshkhandeparkar]

Please describe the problem (or idea)

The Contrast module currently uses extraManipulation but the manipulation process is repetitive so it could use changePixel instead which would also WebAssembly accelerate it

Current Code:

image-sequencer/src/modules/Contrast/Contrast.js

Lines 5 to 25 in 12c422a

	let oldpix = _.cloneDeep(pixels);
	contrast = Number(contrast);
	if (contrast < -100) contrast = -100;
	if (contrast > 100) contrast = 100;
	contrast = (100.0 + contrast) / 100.0;
	contrast *= contrast;
	for (let i = 0; i < pixels.shape[0]; i++) {
	for (let j = 0; j < pixels.shape[1]; j++) {
	var rgbarray = [oldpix.get(i, j, 0) / 255.0, oldpix.get(i, j, 1) / 255.0, oldpix.get(i, j, 2) / 255.0];
	for(var idx = 0;idx < 3;idx++){
	rgbarray[idx] -= 0.5;
	rgbarray[idx] *= contrast;
	rgbarray[idx] += 0.5;
	rgbarray[idx] *= 255;
	if (rgbarray[idx] < 0) rgbarray[idx] = 0;
	if (rgbarray[idx] > 255) rgbarray[idx] = 255;
	}
	pixelSetter(i, j, rgbarray, pixels);

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[rishabhshuklax]

Can I claim this issue?