【Android】圖片切角，切指定的邊。

公司的項目，UI和應用都是我自己做的。前幾天設計了一個UI，出現了半邊圓角的情況，如下圖片所示。圖片都來自服務器，肯定不能要求返回的圖片按這個格式，必須在應用端對圖片進行切角。

[img]http://dl.iteye.com/upload/attachment/0076/3563/a2d626b6-d91c-3bfe-a804-6a940cbe6266.jpg[/img]

Google了好久，發現能找到的代碼都是重複的，而且代碼垃圾很多。於是按着那段代碼的解決方式，自己寫了一個實現指定切某一邊的工具類。

直接可用的代碼：

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 : 橋下一粒砂
 * @email  : [email protected]
 * @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;

    /**
     * 
     * 指定圖片的切邊，對圖片進行圓角處理
     * @param type 具體參見：{@link BitmapFillet.ALL} , {@link BitmapFillet.TOP} , 
     * 				{@link BitmapFillet.LEFT} , {@link BitmapFillet.RIGHT} , {@link BitmapFillet.BOTTOM}
     * @param bitmap 需要被切圓角的圖片
     * @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：先建立一個與圖片大小相同的透明的Bitmap畫板
        	// 然後在畫板上畫出一個想要的形狀的區域。
        	// 最後把源圖片帖上。
        	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)); 
            //帖子圖
            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);
    }
}