ContrastProcessor.java

package at.favre.lib.dali.builder.processor;

import android.graphics.Bitmap;
import android.support.v8.renderscript.Allocation;
import android.support.v8.renderscript.RenderScript;

import at.favre.lib.dali.ScriptC_contrast;

/**
 * This will change the contrast of a bitmap.
 * It uses a renderscript (contrast.rs)
 *
 * contrast values are from -100 to +100
 */
public class ContrastProcessor implements IBitmapProcessor {
	private RenderScript rs;
	private float contrast;

	public ContrastProcessor(RenderScript rs, float contrast) {
		this.rs = rs;
		this.contrast = contrast;
	}

	@Override
	public Bitmap manipulate(Bitmap original) {
		if(contrast != 0) {
			Allocation input = Allocation.createFromBitmap(rs, original);
			final Allocation output = Allocation.createTyped(rs, input.getType());
			ScriptC_contrast mScript = new ScriptC_contrast(rs);
			mScript.invoke_setBright(contrast);
			mScript.forEach_contrast(input, output);
			output.copyTo(original);
		}
		return original;
	}

	@Override
	public String getProcessorTag() {
		return this.getClass().getSimpleName()+": "+contrast;
	}
}