前度时间做的一个项目中有这样的需求，把网络请求下来的图片变为圆形图片显示在客服端。开始想了很久，都没找到好的解决方案，最后还是通过Bitmap.createBitmap方法解决的。具体实现如下：

将图片转换为圆形图片，输入需要一个Bitmap的对象

/**

* 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;

left = 0;

top = 0;

right = width;

bottom = 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);

new RectF(dst);

paint.setAntiAlias(true);// 设置画笔无锯齿

canvas.drawARGB(0, 0, 0, 0); // 填充整个Canvas

paint.setColor(color);

canvas.drawCircle(roundPx, roundPx, roundPx, paint);

paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));// 设置两张图片相交时的模式,参考http://trylovecatch.iteye.com/blog/1189452

canvas.drawBitmap(bitmap, src, dst, paint); // 以Mode.SRC_IN模式合并bitmap和已经draw了的Circle

return output;

}

将drawable中的图片转为Bitmap对象

/**

* drawable2Bitmap

*

*@param bitmap

* 传入Drawable对象

*@return

*/

@SuppressWarnings("deprecation")

public static Bitmap drawable2Bitmap(int a ,Context context) {

Resources resources = context.getResources();

Drawable drawable = resources.getDrawable(a);

if (drawable instanceof BitmapDrawable) {

return ((BitmapDrawable) drawable).getBitmap();

} else if (drawable instanceof NinePatchDrawable) {

Bitmap bitmap = Bitmap

.createBitmap(

drawable.getIntrinsicWidth(),

drawable.getIntrinsicHeight(),

drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888

: Bitmap.Config.RGB_565);

Canvas canvas = new Canvas(bitmap);

drawable.setBounds(0, 0, drawable.getIntrinsicWidth(),

drawable.getIntrinsicHeight());

drawable.draw(canvas);

return bitmap;

} else {

return null;

}

}

图片旋转

/**

* rotateImage

*

* @param id

* 传入derawable id

* @return bitmap

*/

public Bitmap rotateImage(int id,Context context,float rotate){

Bitmap bitmap = ((BitmapDrawable) context.getResources().getDrawable(id)).getBitmap();

Matrix matrix = new Matrix();

matrix.setRotate(rotate);

bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);

return bitmap;

}