android 图片LOMO效果

import android.graphics.Bitmap;
import android.graphics.Color;

public class LomoFilter {
	public static Bitmap filter(Bitmap bitmap){
		int width = bitmap.getWidth();
    	int height = bitmap.getHeight();
    	int dst[] = new int[width*height];
    	bitmap.getPixels(dst, 0, width, 0, 0, width, height);
    	
    	int ratio = width > height ? height*32768/width : width*32768/height;
    	int cx = width >> 1;
		int cy = height >> 1;
		int max = cx * cx + cy * cy;
		int min = (int) (max * (1 - 0.8f));
		int diff = max - min;
		
		int ri, gi, bi;
    	int dx, dy, distSq, v;
    	
    	int R, G, B;
    	
    	int value;
    	int pos, pixColor;
    	int newR, newG, newB;
    	for(int y=0; y<height; y++){
    		for(int x=0; x<width; x++){
    			pos = y*width + x;
    			pixColor = dst[pos];
    			R = Color.red(pixColor);		
    			G = Color.green(pixColor);		
    			B = Color.blue(pixColor);
    			
    			value = R<128 ? R : 256-R;
    			newR = (value*value*value)/64/256;
    			newR = (R<128 ? newR : 255-newR);
    			
    			value = G<128 ? G : 256-G;
    			newG = (value*value)/128;
    			newG = (G<128 ? newG : 255-newG);
    			
    			newB = B/2 + 0x25;	
    			
    			//==========边缘黑暗==============//
    			dx = cx - x;
				dy = cy - y;
				if (width > height) 
					dx = (dx * ratio) >> 15;
				else 
					dy = (dy * ratio) >> 15;
    			
    			distSq = dx * dx + dy * dy;
    			if (distSq > min){
                    v = ((max - distSq) << 8) / diff;
                    v *= v;

                    ri = (int)(newR * v) >> 16;
                    gi = (int)(newG * v) >> 16;
                    bi = (int)(newB * v) >> 16;

                    newR = ri > 255 ? 255 : (ri < 0 ? 0 : ri);
                    newG = gi > 255 ? 255 : (gi < 0 ? 0 : gi);
                    newB = bi > 255 ? 255 : (bi < 0 ? 0 : bi);
	            }
    			//==========边缘黑暗end==============//
    			
    			dst[pos] = Color.rgb(newR, newG, newB);
    		}
    	}

    	Bitmap acrossFlushBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
    	acrossFlushBitmap.setPixels(dst, 0, width, 0, 0, width, height);
    	return acrossFlushBitmap;
	}
}