android中实现从一个图片中截取一部分，在翻转，成一个圆形显示

效果图如下：

MyView 类

public class MyView extends View {    Bitmap bmp;    Paint paint = new Paint();    public MyView(Context context) {        super(context);    }    public MyView(Context context, AttributeSet attrs) {        super(context, attrs);        bmp = BitmapFactory.decodeResource(getResources(), R.mipmap.c);        src = new RectF(bmp.getWidth() / 2 - 50, bmp.getHeight() / 2 - 50, bmp.getWidth() / 2 + 50, bmp.getHeight() / 2 + 50);        dst = new Rect(200, 200, 400, 400);        paint.setAntiAlias(true);        paint.setDither(true);        Shader shaer = new BitmapShader(bmp, Shader.TileMode.MIRROR, Shader.TileMode.REPEAT);        paint.setShader(shaer);    }    private RectF src = null;    private Rect dst = null;    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        //绘制Bitmap        Matrix m = new Matrix();        //每次set都会重置矩形        m.setRotate(90, bmp.getWidth() / 2, bmp.getHeight() / 2);        m.postTranslate(100, 100);        m.preScale(0.5f, 0.5f, bmp.getWidth() / 2, bmp.getHeight() / 2);        //错切        m.postSkew(0.3f, 0.3f);        // canvas.drawBitmap(bmp, m, null);        // canvas.drawBitmap(bmp, src, dst, null);        //拿view的高宽        canvas.drawArc(src, 100, 270, true, paint);    }}

MainActivity 类

public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);    }}

xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_main"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    tools:context="com.example.administrator.lesson12_drawbitmap.MainActivity">    <com.example.administrator.lesson12_drawbitmap.MyView        android:layout_width="wrap_content"        android:layout_height="wrap_content" />LinearLayout>

效果图如下：

MyView 类

MainActivity 类

xml

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