Android 两点缩放图片
Android 两点缩放图片
Android 两点缩放图片:
本文工程源码下载:
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具体下载目录在 /pub/Android源码集锦/2011年/11月/Android 两点缩放图片/
- package mutl.touch.sample;
- import android.app.Activity;
- import android.graphics.Matrix;
- import android.graphics.PointF;
- import android.os.Bundle;
- import android.util.FloatMath;
- import android.view.MotionEvent;
- import android.view.View;
- import android.view.View.OnTouchListener;
- import android.widget.ImageView;
- public class Main extends Activity
- {
- private static final int NONE = 0;
- private static final int DRAG = 1;
- private static final int ZOOM = 2;
- private int mode = NONE;
- private float oldDist;
- private Matrix matrix = new Matrix();
- private Matrix savedMatrix = new Matrix();
- private PointF start = new PointF();
- private PointF mid = new PointF();
- @Override
- public void onCreate(Bundle savedInstanceState)
- {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- ImageView view = (ImageView) findViewById(R.id.image_view);
- view.setOnTouchListener(new OnTouchListener()
- {
- @Override
- public boolean onTouch(View v, MotionEvent event)
- {
- ImageView view = (ImageView) v;
- switch (event.getAction() & MotionEvent.ACTION_MASK)
- {
- case MotionEvent.ACTION_DOWN:
- savedMatrix.set(matrix);
- start.set(event.getX(), event.getY());
- mode = DRAG;
- break;
- case MotionEvent.ACTION_UP:
- case MotionEvent.ACTION_POINTER_UP:
- mode = NONE;
- break;
- case MotionEvent.ACTION_POINTER_DOWN:
- oldDist = spacing(event);
- if (oldDist > 10f)
- {
- savedMatrix.set(matrix);
- midPoint(mid, event);
- mode = ZOOM;
- }
- break;
- case MotionEvent.ACTION_MOVE:
- if (mode == DRAG)
- {
- matrix.set(savedMatrix);
- matrix.postTranslate(event.getX() - start.x,
- event.getY() - start.y);
- }
- else if (mode == ZOOM)
- {
- float newDist = spacing(event);
- if (newDist > 10f)
- {
- matrix.set(savedMatrix);
- float scale = newDist / oldDist;
- matrix.postScale(scale, scale, mid.x, mid.y);
- }
- }
- break;
- }
- // 图片设置矩阵
- view.setImageMatrix(matrix);
- return true;
- }
- private float spacing(MotionEvent event)
- {
- float x = event.getX(0) - event.getX(1);
- float y = event.getY(0) - event.getY(1);
- return FloatMath.sqrt(x * x + y * y);
- }
- private void midPoint(PointF point, MotionEvent event)
- {
- float x = event.getX(0) + event.getX(1);
- float y = event.getY(0) + event.getY(1);
- point.set(x / 2, y / 2);
- }
- });
- }
- }
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