android实现图片按任意路径截取

该文转自http://blog.csdn.net/xiaoxiaobian3310903/article/details/7760555

使用 Android提供的Path实現图片的截取

重写View的onTouchEvent方法和onDraw方法,onTouchEvent负责实现截取路径的构件,onDraw进行刷新页面,重写View类的代码如下 :

    public class MyView extends View {          private Drawable mDrawable;          private Path mPath;          private float mX = -1;          private float mY = -1;          private float mPastX;          private float mPastY;                    public MyView(Context context) {              super(context);              // TODO Auto-generated constructor stub              mPath = new Path();          }                public void setDrawable(Drawable pDrawable){              mDrawable = pDrawable;          }                @Override          protected void onDraw(Canvas canvas) {              // TODO Auto-generated method stub              super.onDraw(canvas);              Log.i("xiao", "onDraw");              mDrawable.setBounds(0, 0, getWidth(), getHeight());              Rect lRect = mDrawable.getBounds();              Log.i("xiao", "lRect.left =  " + lRect.left + " top = " + lRect.top + " right = " + lRect.right + " bottom = " + lRect.bottom);              if(!mPath.isEmpty()){                  Log.i("xiao", "!mPath.isEmpty()");                  canvas.clipPath(mPath);                  //mDrawable.draw(canvas);              }                            mDrawable.draw(canvas);          }                @Override          public boolean onTouchEvent(MotionEvent event) {              // TODO Auto-generated method stub              Log.i("xiao", "onTouchEvent");              int lAction = event.getAction();              if(mX != -1){                  mPastX = mX;                  mPastY = mY;              }              mX = event.getX();              mY = event.getY();              switch(lAction){              case MotionEvent.ACTION_DOWN:                  mPath.reset();                  mPath.moveTo(mX, mY);                  break;              case MotionEvent.ACTION_MOVE:                  mPath.quadTo(mPastX, mPastY, (mX + mPastX) / 2, (mY + mPastY) / 2);                  break;              case MotionEvent.ACTION_UP:                  mPath.lineTo(mX, mY);                  mX = -1;                  mY = -1;                  invalidate();                  break;              default:                                    break;              }              return true;          }      }

Activity主要负责获取和设置Drawable和设置布局,代码如下:

    private MyView mView;                     @Override          public void onCreate(Bundle savedInstanceState) {              super.onCreate(savedInstanceState);                            mView = new MyView(this);              mView.setDrawable(this.getResources().getDrawable(R.drawable.test1));              this.setContentView(mView);          }

未截取时效果:

画一个路径截取效果图:

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