sketcher2/src/com/jotuntech/sketcher/common/filter/BlurFilter.java

package com.jotuntech.sketcher.common.filter;

import com.jotuntech.sketcher.common.Pixels;

public class BlurFilter implements Filter {
	float xAlpha, xRed, xGreen, xBlue, cutoff;
	float[] yAlpha, yRed, yGreen, yBlue;
	int width, height, x, y;
	boolean xAlphaWait = false;
	boolean[] yAlphaWait;
	
	public BlurFilter() {
		
	}
	
	public void setSize(int width, int height) {
		this.width = width;
		this.height = height;
	}

	public void setParameterA(float a) {
		this.cutoff = 1 / a;
	}

	public void setParameterB(float b) { }

	public void setParameterC(float c) { }

	public int processPass1Pixel(int pixel) {
		float inAlpha = Pixels.getChannel0(pixel);
		float inRed = Pixels.getChannel1(pixel);
		float inGreen = Pixels.getChannel2(pixel);
		float inBlue = Pixels.getChannel3(pixel);

		float outAlpha, outRed, outGreen, outBlue;
		if(x == 0) {
			xAlpha = inAlpha;
			xRed = inRed;
			xGreen = inGreen;
			xBlue = inBlue;
		} else {
			xAlpha += (inAlpha - xAlpha) * cutoff;
			if(inAlpha < 1) {
				xAlphaWait = true;
			} else {
				xAlphaWait = false;
				xRed += (inRed - xRed) * cutoff;
				xGreen += (inGreen - xGreen) * cutoff;
				xBlue += (inBlue - xBlue) * cutoff;
			}
		}
				
		if(y == 0) {
			outAlpha = xAlpha;
			outRed = xRed;
			outGreen = xGreen;
			outBlue = xBlue;
		} else {
			outAlpha = yAlpha[x] + (xAlpha - yAlpha[x]) * cutoff;
			if(xAlpha < 1) {
				yAlphaWait[x] = true;
				outRed = yRed[x];
				outGreen = yGreen[x];
				outBlue = yBlue[x];
			} else {
				yAlphaWait[x] = false;
				outRed = yRed[x] + (xRed - yRed[x]) * cutoff;
				outGreen = yGreen[x] + (xGreen - yGreen[x]) * cutoff;
				outBlue = yBlue[x] + (xBlue - yBlue[x]) * cutoff;
			}
		}
		
		yAlpha[x] = outAlpha;
		yRed[x] = outRed;
		yGreen[x] = outGreen;
		yBlue[x] = outBlue;
		
		if(++x == width) {
			x = 0;
			++y;
		}

		return Pixels.pack((int) outAlpha, (int) outRed, (int) outGreen, (int) outBlue);
	}
	
	public int processPass2Pixel(int pixel) {
		return processPass1Pixel(pixel);
	}

	public boolean isPass1ReadOnly() {
		return false;
	}
	
	public boolean hasPass2() {
		return true;
	}
	
	public boolean isPass2Reversed() {
		return true;
	}
	
	public void startPass1() {
		x = 0;
		y = 0;
		xAlpha = 0;
		xRed = 0;
		xGreen = 0;
		xBlue = 0;
		yAlpha = new float[width];
		yRed = new float[width];
		yGreen = new float[width];
		yBlue = new float[width];
		xAlphaWait = false;
		yAlphaWait = new boolean[width];
	}
	
	public void startPass2() {
		startPass1();
	}
}