Android 指定角的圓角圖片處理

 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 :
@email  
@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
 // 然后在畫板上畫出一個想要的形狀的區域。
 // 最后把源圖片帖上。
 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);
}
}</pre>