【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);

    }

}

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