Android图像处理之绘制圆形、三角形及扇形的头像

public class CircleImageView extends View { private Paint mPaint; private Paint mTargetPaint; private Bitmap mSourceBitmap; private Bitmap mTargetBitmap; private Canvas mTargetCanvas; private int mWidth; private int mHeight; public CircleImageView(Context context) {  this(context, null); } public CircleImageView(Context context, AttributeSet attrs) {  this(context, attrs, 0); } public CircleImageView(Context context, AttributeSet attrs, int defStyleAttr) {  super(context, attrs, defStyleAttr);  init(); } private void init() {  mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);  mTargetPaint = new Paint(Paint.ANTI_ALIAS_FLAG);  mTargetPaint.setXfermode(new PorterDuffXfermode(SRC_IN));  mSourceBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.xiaojiangshi);  mTargetBitmap = Bitmap.createBitmap(mSourceBitmap.getWidth(), mSourceBitmap.getHeight(), Bitmap.Config.ARGB_8888);  mTargetCanvas = new Canvas(mTargetBitmap); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {  super.onSizeChanged(w, h, oldw, oldh);  mWidth = w;  mHeight = h; } @Override protected void onDraw(Canvas canvas) {  // 生成圆形Bitmap过程.  int radius = Math.min(mWidth, mHeight) / 2;  // 先绘制圆形  mTargetCanvas.drawCircle(mWidth / 2, mHeight / 2, radius, mPaint);  // 再绘制Bitmap  mTargetCanvas.drawBitmap(mSourceBitmap, 0, 0, mTargetPaint);  canvas.drawBitmap(mTargetBitmap, 0, 0, null); }}