【Android】图片切角，切指定的边。

 

公司的项目，UI和应用都是我自己做的。前几天设计了一个UI，出现了半边圆角的情况，如下图片所示。图片都来自服务器，肯定不能要求返回的图片按这个格式，必须在应用端对图片进行切角。 

 

Google了好久，发现能找到的代码都是重复的，而且代码垃圾很多。于是按着那段代码的解决方式，自己写了一个实现指定切某一边的工具类。 

直接可用的代码： 

package com.lurencun.androidsysteminfomation;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;

/**
 * @author : 桥下一粒砂
 * @email  : chenyoca@gmail.com
 * @date   : 2012-11-8
 * @desc   :
 */
public class BitmapFillet {

    public static final int ALL = 347120;
    public static final int TOP = 547120;
    public static final int LEFT = 647120;
    public static final int RIGHT = 747120;
    public static final int BOTTOM = 847120;

    /**
     *
     * 指定图片的切边，对图片进行圆角处理
     * @param type 具体参见：{@link BitmapFillet.ALL} , {@link BitmapFillet.TOP} ,
     *              {@link BitmapFillet.LEFT} , {@link BitmapFillet.RIGHT} , {@link BitmapFillet.BOTTOM}
     * @param bitmap 需要被切圆角的图片
     * @param roundPx 要切的像素大小
     * @return
     *
     */
    public static Bitmap fillet(int type,Bitmap bitmap,int roundPx) {
        try {
            // 其原理就是：先建立一个与图片大小相同的透明的Bitmap画板
            // 然后在画板上画出一个想要的形状的区域。
            // 最后把源图片帖上。
            final int width = bitmap.getWidth();
            final int height = bitmap.getHeight();

            Bitmap paintingBoard = Bitmap.createBitmap(width,height, Config.ARGB_8888);
            Canvas canvas = new Canvas(paintingBoard);
            canvas.drawARGB(Color.TRANSPARENT, Color.TRANSPARENT, Color.TRANSPARENT, Color.TRANSPARENT);

            final Paint paint = new Paint();
            paint.setAntiAlias(true);
            paint.setColor(Color.BLACK);

            if( TOP == type ){
                clipTop(canvas,paint,roundPx,width,height);
            }else if( LEFT == type ){
                 clipLeft(canvas,paint,roundPx,width,height);
            }else if( RIGHT == type ){
                clipRight(canvas,paint,roundPx,width,height);
            }else if( BOTTOM == type ){
                clipBottom(canvas,paint,roundPx,width,height);
            }else{
                clipAll(canvas,paint,roundPx,width,height);
            }

            paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
            //帖子图
            final Rect src = new Rect(0, 0, width, height);
            final Rect dst = src;
            canvas.drawBitmap(bitmap, src, dst, paint);
            return paintingBoard;
        } catch (Exception exp) {
            return bitmap;
        }
    }

    private static void clipLeft(final Canvas canvas,final Paint paint,int offset,int width,int height){
        final Rect block = new Rect(offset,0,width,height);
        canvas.drawRect(block, paint);
        final RectF rectF = new RectF(0, 0, offset * 2 , height);
        canvas.drawRoundRect(rectF, offset, offset, paint);
    }

    private static void clipRight(final Canvas canvas,final Paint paint,int offset,int width,int height){
        final Rect block = new Rect(0, 0, width-offset, height);
        canvas.drawRect(block, paint);
        final RectF rectF = new RectF(width - offset * 2, 0, width , height);
        canvas.drawRoundRect(rectF, offset, offset, paint);
    }

    private static void clipTop(final Canvas canvas,final Paint paint,int offset,int width,int height){
        final Rect block = new Rect(0, offset, width, height);
        canvas.drawRect(block, paint);
        final RectF rectF = new RectF(0, 0, width , offset * 2);
        canvas.drawRoundRect(rectF, offset, offset, paint);
    }

    private static void clipBottom(final Canvas canvas,final Paint paint,int offset,int width,int height){
        final Rect block = new Rect(0, 0, width, height - offset);
        canvas.drawRect(block, paint);
        final RectF rectF = new RectF(0, height - offset * 2 , width , height);
        canvas.drawRoundRect(rectF, offset, offset, paint);
    }

    private static void clipAll(final Canvas canvas,final Paint paint,int offset,int width,int height){
        final RectF rectF = new RectF(0, 0, width , height);
        canvas.drawRoundRect(rectF, offset, offset, paint);
    }
}