Android 将一张图片变为圆形图片

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;}