【转】四、android图像特效处理之底片效果

这篇将讲到图片特效处理的底片效果。跟前面一样是对像素点进行处理，算法是通用的。

算法原理：将当前像素点的RGB值分别与255之差后的值作为当前点的RGB值。

例：

ABC

求B点的底片效果：

B.r = 255 - B.r;

B.g = 255 - B.g;

B.b = 255 - B.b;

效果图：

原图：

代码：

package com.color;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.widget.ImageView;

public class ColorView extends ImageView {

    private Paint myPaint = null;
    private Bitmap bitmap = null;
    private int width,height;
    private int[] oldPixels;  
    private int[] newPixels;  
    private int color,color2;
    private int pixelsR,pixelsG,pixelsB,pixelsA,pixelsR2,pixelsG2,pixelsB2;
    
    public ColorView(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        bitmap = BitmapFactory.decodeResource(context.getResources(),R.drawable.ww); 
        width = bitmap.getWidth();  
        height = bitmap.getHeight();
        oldPixels = new int[width*height]; 
        newPixels = new int[width*height];
        invalidate();
    }
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas); 
        //获取像素
        bitmap.getPixels(oldPixels, 0, width, 0, 0, width, height);
        
        for(int i = 1;i < height*width; i++){
                color = oldPixels[i];
                //获取RGB分量
                pixelsA = Color.alpha(color);
                pixelsR = Color.red(color);
                pixelsG = Color.green(color);
                pixelsB = Color.blue(color);
                
                //转换
                pixelsR = (255 - pixelsR);
                pixelsG = (255 - pixelsG);
                pixelsB = (255 - pixelsB);
                //均小于等于255大于等于0
                if(pixelsR > 255){
                    pixelsR = 255;
                }
                else if(pixelsR < 0){
                    pixelsR = 0;
                }
                if(pixelsG > 255){
                    pixelsG = 255;
                }
                else if(pixelsG < 0){ 
                    pixelsG = 0;
                }
                if(pixelsB > 255){
                    pixelsB = 255;
                }
                else if(pixelsB < 0){
                    pixelsB = 0;
                }
                //根据新的RGB生成新像素
                newPixels[i] = Color.argb(pixelsA, pixelsR, pixelsG, pixelsB);
                
        }
        //根据新像素生成新图片
        bitmap.setPixels(newPixels, 0, width, 0, 0, width, height);
        canvas.drawBitmap(bitmap,0,0,myPaint);
    }
}