import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.RectF;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
public class RoundRect {
  private int width;
  private int height;
  private float cornerRadius;
  /**
   * 用于初始化圓角矩形基本參數(shù)
   *
   * @param width    圖片寬度
   * @param height    圖片高度
   * @param cornerRadius 圓角半徑
   */
  public RoundRect(int width, int height, float cornerRadius) {
    this.width = width;
    this.height = height;
    this.cornerRadius = cornerRadius;
  }
  /**
   * 用于把普通圖片轉(zhuǎn)換為圓角矩形圖像
   *
   * @param path 圖片路徑
   * @return output 轉(zhuǎn)換后的圓角矩形圖像
   */
  Bitmap toRoundRect(String path) {
    //創(chuàng)建位圖對象
    Bitmap photo = lessenUriImage(path);
    return Transformation(photo);
  }
  /**
   * 用于把普通圖片轉(zhuǎn)換為圓角矩形圖像
   *
   * @param imageID 圖片資源ID
   * @param context 上下文對象
   * @return output 轉(zhuǎn)換后的圓角矩形圖像
   */
  Bitmap toRoundRect(Context context, int imageID) {
    //創(chuàng)建位圖對象
    Bitmap photo = BitmapFactory.decodeResource(context.getResources(), imageID);
    return Transformation(photo);
  }
  /**
   * 用于把Uri圖片轉(zhuǎn)換為Bitmap對象
   *
   * @param path 圖片URI地址
   * @return 生成的Bitmap對象
   */
  public final static Bitmap lessenUriImage(String path) {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    Bitmap bitmap = BitmapFactory.decodeFile(path, options); //此時返回 bm 為空
    options.inJustDecodeBounds = false; //縮放比。由于是固定比例縮放，只用高或者寬其中一個數(shù)據(jù)進(jìn)行計算即可
    int be = (int) (options.outHeight / (float) 320);
    if (be <= 0) be = 1;
    options.inSampleSize = be; //重新讀入圖片，注意此時已經(jīng)把 options.inJustDecodeBounds 設(shè)回 false 了
    bitmap = BitmapFactory.decodeFile(path, options);
    int w = bitmap.getWidth();
    int h = bitmap.getHeight();
    System.out.println(w + " " + h); //after zoom
    return bitmap;
  }
  /**
   * 用于把Bitmap圖像轉(zhuǎn)換為圓角圖像
   *
   * @param photo 需要轉(zhuǎn)換的Bitmap對象
   * @return 轉(zhuǎn)換成圓角的Bitmap對象
   */
  private Bitmap Transformation(Bitmap photo) {
    //根據(jù)源文件新建一個darwable對象
    Drawable imageDrawable = new BitmapDrawable(photo);
    // 新建一個新的輸出圖片
    Bitmap output = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(output);
    // 新建一個矩形
    RectF outerRect = new RectF(0, 0, width, height);
    // 產(chǎn)生一個紅色的圓角矩形
    Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    paint.setColor(Color.RED);
    canvas.drawRoundRect(outerRect, cornerRadius, cornerRadius, paint);
    // 將源圖片繪制到這個圓角矩形上
    paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
    imageDrawable.setBounds(0, 0, width, height);
    canvas.saveLayer(outerRect, paint, Canvas.ALL_SAVE_FLAG);
    imageDrawable.draw(canvas);
    canvas.restore();
    return output;
  }
}

public class MainActivity extends Activity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.image);
    ImageView image = (ImageView)findViewById(R.id.image);
    RoundRect roundRect = new RoundRect(500,500,100);
    Bitmap photo = roundRect.toRoundRect(this,R.drawable.kms);
    image.setImageBitmap(photo);
  }
}

public class MainActivity extends Activity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.image);
    ImageView image = (ImageView)findViewById(R.id.image);
    RoundRect roundRect = new RoundRect(500,500,300);
    Bitmap photo = roundRect.toRoundRect(this,R.drawable.indark);
    image.setImageBitmap(photo);
  }
}