【Android通过手势实现的缩放处理】

android自定义手势缩放控件
http://www.eoeandroid.com/thread-164077-1-1.html

【eoeAndroid社区索引】图形图像之图像处理(缩放　旋转　转化)
http://www.eoeandroid.com/thread-173242-1-1.html

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今天在http://www.eoeandroid.com/看到这个不错的技术点，拿出来分享一下，希望大家能够一起学习成长

import android.app.Activity;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.os.Bundle;import android.util.DisplayMetrics;import android.view.MotionEvent;import android.view.View;/** * ... *  * @author vlinux *  */public class MultiTouchTestActivity extends Activity {/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// setContentView(R.layout.main);View view = new MultiTouchView(this);setContentView(view);}class MultiTouchView extends View {private float x1;private float y1;private float x2;private float y2;public MultiTouchView(Context context) {super(context);// TODO Auto-generated constructor stub}@Overridepublic boolean onTouchEvent(MotionEvent event) {// TODO Auto-generated method stubfloat size = event.getSize();int szi = (int) size;int dxi = szi >> 12;int dyit = ((1 << 12) - 1);int dyi = szi & dyit;DisplayMetrics metrics = getResources().getDisplayMetrics();float dx = metrics.widthPixels * dxi / (float) dyit;float dy = metrics.heightPixels * dyi / (float) dyit;x1 = event.getX();y1 = event.getY();x2 = x1 + dx;y2 = y1 + dy;invalidate();return true;}@Overrideprotected void onDraw(Canvas canvas) {// TODO Auto-generated method stubsuper.onDraw(canvas); float r = (float) Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2)* (y1 - y2)) / 2;r = 50 >= r ? 50 : r;Paint paint = new Paint();paint.setColor(Color.BLUE);canvas.drawCircle(x1, y1, r, paint);}

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