android 圆角图片 处理

/* 将头像转为圆形 */
Resources res = getResources();
Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.head);
head.setImageBitmap(ImageHelper.toRoundBitmap(bmp));

//处理类
public class ImageHelper {
/**
* 转换图片成圆形
* @param bitmap 传入Bitmap对象
* @return
*/
public static Bitmap toRoundBitmap(Bitmap bitmap) {
int width = bitmap.getWidth();
int height = bitmap.getHeight();
float roundPx;
float left,top,right,bottom,dst_left,dst_top,dst_right,dst_bottom;
if (width <= height) {
roundPx = width / 2;
top = 0;
bottom = width;
left = 0;
right = width;
height = width;
dst_left = 0;
dst_top = 0;
dst_right = width;
dst_bottom = width;
} else {
roundPx = height / 2;
float clip = (width - height) / 2;
left = clip;
right = width - clip;
top = 0;
bottom = height;
width = height;
dst_left = 0;
dst_top = 0;
dst_right = height;
dst_bottom = height;
}

Bitmap output = Bitmap. createBitmap(width,
height, Config. ARGB_8888);
Canvas canvas = new Canvas(output);

final int color = 0xff424242;
final Paint paint = new Paint();
final Rect src = new Rect((int)left, ( int)top, (int)right, (int)bottom);
final Rect dst = new Rect((int)dst_left, ( int)dst_top, (int)dst_right, (int)dst_bottom);
final RectF rectF = new RectF(dst);

paint.setAntiAlias( true);

canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);

paint.setXfermode( new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, src, dst, paint);
return output;
}

// 下载图片转为bitmap
public static Bitmap getHttpBitmap(String url) {
URL u = null;
Bitmap bmp = null;
try {
u = new URL(url);

} catch (Exception e) {
// TODO: handle exception
}
try {
HttpURLConnection conn = (HttpURLConnection) u.openConnection();
conn.setConnectTimeout(0);
conn.setDoInput( true);
conn.connect();
InputStream ins = conn.getInputStream();
bmp = BitmapFactory. decodeStream(ins);
ins.close();
} catch (Exception e) {
// TODO: handle exception
}
return bmp;
}
}