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); } }