Android自定义View实现圆形切图效果

private void init() {  getBitmapFromDrawable();  if (mBitmap == null) {   return;  }  mShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);  // bitmap paint  mFillPaint = new Paint();  mFillPaint.setAntiAlias(true);  mFillPaint.setStyle(Paint.Style.FILL);  mFillPaint.setShader(mShader);  // border paint  mBoundPaint = new Paint();  mBoundPaint.setAntiAlias(true);  mBoundPaint.setStyle(Paint.Style.STROKE);  mBoundPaint.setStrokeWidth(mBorderWidth);  mBoundPaint.setColor(mBorderColor);  // border rectF  mBorderBound.set(calculateBitmapBound());  // bitmap rectF  mBitmapBound.set(calculateBitmapBound());  mBitmapBound.inset(mBorderWidth - 10, mBorderWidth - 10);  updateShaderMatrix(); }

private Bitmap getBitmapFromDrawable() {  Drawable drawable = getDrawable();  if (drawable instanceof BitmapDrawable) {   mBitmap = ((BitmapDrawable) drawable).getBitmap();   mBitmapWidth = mBitmap.getWidth();   mBitmapHeight = mBitmap.getHeight();   return mBitmap;  }  return null; }

 /**  * 计算Bitmap边距  */ private RectF calculateBitmapBound() {  int availableWidth = getWidth() - getPaddingLeft() - getPaddingRight();  int availableHeight = getHeight() - getPaddingTop() - getPaddingBottom();  int sideLength = Math.min(availableWidth, availableHeight); // 可用的直径  mRadius = sideLength / 2;  int left = getPaddingLeft() + (availableWidth - sideLength) / 2;  int top = getPaddingTop() + (availableHeight - sideLength) / 2;  Log.d(TAG, "calculateBitmapBound: left >>> " + left + " top >>> " + top + " right >>> "    + (left + sideLength) + " right >>> " + top + " bottom >>> " + (top + sideLength));  return new RectF(left, top, left + sideLength, top + sideLength); }

 /**  * 调整图片缩放,目前只支持CenterCrop  */ private void updateShaderMatrix() {  float scale;  float dx = 0;  float dy = 0;  mShaderMatrix.set(null);  // 调整缩放,使图片居中  if (mBitmapWidth * mBitmapBound.height() > mBitmapBound.width() * mBitmapHeight) {   scale = mBitmapBound.height() / (float) mBitmapHeight;   dx = (mBitmapBound.width() - mBitmapWidth * scale) * 0.5f;  } else {   scale = mBitmapBound.width() / (float) mBitmapWidth;   dy = (mBitmapBound.height() - mBitmapHeight * scale) * 0.5f;  }  Log.d(TAG, "updateShaderMatrix: scale >>> " + scale);  mShaderMatrix.setScale(scale, scale);  // TODO: 16-10-15 http://chroya.iteye.com/blog/713869  // 回到中心点,便于下次缩放  mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBitmapBound.left, (int) (dy + 0.5f) + mBitmapBound.top);  mShader.setLocalMatrix(mShaderMatrix); }

 @Override protected void onDraw(Canvas canvas) {  if (mBitmap == null) {   super.onDraw(canvas);  }  Log.d(TAG, "onDraw: centerX >>> " + mBitmapBound.centerX() + " centerY >>> " + mBitmapBound.centerY());  canvas.drawCircle(mBitmapBound.centerX(), mBitmapBound.centerY(), mRadius, mFillPaint);  // 绘制边框  canvas.drawCircle(mBorderBound.centerX(), mBorderBound.centerY(), mRadius, mBoundPaint); }

/** * Created by shixi_tianrui1 on 16-10-7. * 显示圆形图片的ImageView */public class CircleImageView extends ImageView { private static final String TAG = "LOGGER"; private BitmapShader mShader; private Paint mFillPaint; // 绘图 private Paint mBoundPaint; // 绘制圆边 private Bitmap mBitmap; private Drawable mDrawable; private int mBorderColor;  // 边框颜色 private float mBorderWidth;  // 边框宽度 private RectF mBorderBound = new RectF(); private RectF mBitmapBound = new RectF(); private Matrix mShaderMatrix = new Matrix(); private int mRadius; private int mBitmapWidth; private int mBitmapHeight; private static final float DEFAULT_BORDER_WIDTH = 5; 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);  TypedArray a = getResources().obtainAttributes(attrs, R.styleable.CircleImageView);  mBorderColor = a.getColor(R.styleable.CircleImageView_borderColor, Color.BLUE);  mBorderWidth = a.getDimension(R.styleable.CircleImageView_borderWidth, DEFAULT_BORDER_WIDTH);  mBorderWidth = a.getDimensionPixelSize(R.styleable.CircleImageView_borderWidth, 20);  a.recycle(); } private void init() {  getBitmapFromDrawable();  if (mBitmap == null) {   return;  }  mShader = new BitmapShader(mBitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);  // bitmap paint  mFillPaint = new Paint();  mFillPaint.setAntiAlias(true);  mFillPaint.setStyle(Paint.Style.FILL);  mFillPaint.setShader(mShader);  // border paint  mBoundPaint = new Paint();  mBoundPaint.setAntiAlias(true);  mBoundPaint.setStyle(Paint.Style.STROKE);  mBoundPaint.setStrokeWidth(mBorderWidth);  mBoundPaint.setColor(mBorderColor);  // border rectF  mBorderBound.set(calculateBitmapBound());  // bitmap rectF  mBitmapBound.set(calculateBitmapBound());  mBitmapBound.inset(mBorderWidth - 10, mBorderWidth - 10);  updateShaderMatrix(); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {  super.onSizeChanged(w, h, oldw, oldh);  init(); } /**  * 计算Bitmap边距  */ private RectF calculateBitmapBound() {  int availableWidth = getWidth() - getPaddingLeft() - getPaddingRight();  int availableHeight = getHeight() - getPaddingTop() - getPaddingBottom();  int sideLength = Math.min(availableWidth, availableHeight); // 可用的直径  mRadius = sideLength / 2;  int left = getPaddingLeft() + (availableWidth - sideLength) / 2;  int top = getPaddingTop() + (availableHeight - sideLength) / 2;  Log.d(TAG, "calculateBitmapBound: left >>> " + left + " top >>> " + top + " right >>> "    + (left + sideLength) + " right >>> " + top + " bottom >>> " + (top + sideLength));  return new RectF(left, top, left + sideLength, top + sideLength); } private Bitmap getBitmapFromDrawable() {  Drawable drawable = getDrawable();  if (drawable instanceof BitmapDrawable) {   mBitmap = ((BitmapDrawable) drawable).getBitmap();   mBitmapWidth = mBitmap.getWidth();   mBitmapHeight = mBitmap.getHeight();   return mBitmap;  }  return null; } @Override protected void onDraw(Canvas canvas) {  if (mBitmap == null) {   super.onDraw(canvas);  }  Log.d(TAG, "onDraw: centerX >>> " + mBitmapBound.centerX() + " centerY >>> " + mBitmapBound.centerY());  canvas.drawCircle(mBitmapBound.centerX(), mBitmapBound.centerY(), mRadius, mFillPaint);  // 绘制边框  canvas.drawCircle(mBorderBound.centerX(), mBorderBound.centerY(), mRadius, mBoundPaint); } /**  * 调整图片缩放,目前只支持CenterCrop  */ private void updateShaderMatrix() {  float scale;  float dx = 0;  float dy = 0;  mShaderMatrix.set(null);  // 调整缩放,使图片居中  if (mBitmapWidth * mBitmapBound.height() > mBitmapBound.width() * mBitmapHeight) {   scale = mBitmapBound.height() / (float) mBitmapHeight;   dx = (mBitmapBound.width() - mBitmapWidth * scale) * 0.5f;  } else {   scale = mBitmapBound.width() / (float) mBitmapWidth;   dy = (mBitmapBound.height() - mBitmapHeight * scale) * 0.5f;  }  Log.d(TAG, "updateShaderMatrix: scale >>> " + scale);  mShaderMatrix.setScale(scale, scale);  // TODO: 16-10-15 http://chroya.iteye.com/blog/713869  // 回到中心点,便于下次缩放  mShaderMatrix.postTranslate((int) (dx + 0.5f) + mBitmapBound.left, (int) (dy + 0.5f) + mBitmapBound.top);  mShader.setLocalMatrix(mShaderMatrix); }}