Android实现图片缩放与旋转

本文使用Matrix实现Android实现图片缩放与旋转。示例代码如下：

 

package com.android.matrix;import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.view.ViewGroup.LayoutParams;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ImageView.ScaleType;

/**
 * Android实现图片缩放与旋转。
 * @author Administrator
 *
 */

 

public class MatixActivity extends Activity {
   public void onCreate(Bundle icicle) {
       
       super.onCreate(icicle);
       
        setTitle("Android实现图片缩放与旋转。");
        LinearLayout linLayout = new LinearLayout(this);
       
       //加载需要操作的图片，这里是一张图片
       Bitmap bitmapOrg = BitmapFactory.decodeResource(getResources(),R.drawable.r);
       
       //获取这个图片的宽和高
       int width = bitmapOrg.getWidth();
       int height = bitmapOrg.getHeight();
       
       //定义预转换成的图片的宽度和高度
       int newWidth = 200;
       int newHeight = 200;
       
       //计算缩放率，新尺寸除原始尺寸
       float scaleWidth = ((float) newWidth) / width;
       float scaleHeight = ((float) newHeight) / height;
       
       // 创建操作图片用的matrix对象
       Matrix matrix = new Matrix();
       
       // 缩放图片动作
       matrix.postScale(scaleWidth, scaleHeight);
       
       //旋转图片 动作
       matrix.postRotate(45);
       
       // 创建新的图片
       Bitmap resizedBitmap = Bitmap.createBitmap(bitmapOrg, 0, 0,
            width, height, matrix, true);
       
       //将上面创建的Bitmap转换成Drawable对象，使得其可以使用在ImageView, ImageButton中
       BitmapDrawable bmd = new BitmapDrawable(resizedBitmap);
       
       //创建一个ImageView
       ImageView imageView = new ImageView(this);
       
       // 设置ImageView的图片为上面转换的图片
       imageView.setImageDrawable(bmd);
       
       //将图片居中显示
       imageView.setScaleType(ScaleType.CENTER);
       
       //将ImageView添加到布局模板中
       linLayout.addView(imageView, new LinearLayout.LayoutParams(
            LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
       
       // 设置为本activity的模板
       setContentView(linLayout);
   }
}

 

Zoom.java文件中代码：

 

package com.android.zooming;

import android.view.View;
import android.content.Context;  
import android.graphics.Canvas;  
import android.graphics.drawable.Drawable;  
import android.view.KeyEvent;  

public class Zoom extends View {
   private Drawable image;  
   private int zoomControler=20;  
    
   public Zoom(Context context){  
       super(context);  
        image=context.getResources().getDrawable(R.drawable.x);    
        setFocusable(true);  
   }  
    
   @Override  
   protected void onDraw(Canvas canvas) {  
       // TODO Auto-generated method stub  
       super.onDraw(canvas);  
       //控制图像的宽度和高度
       image.setBounds((getWidth()/2)-zoomControler, (getHeight()/2)-zoomControler,
           (getWidth()/2)+zoomControler, (getHeight()/2)+zoomControler);  
        image.draw(canvas);  
   }  
    
   @Override  
   public boolean onKeyDown(int keyCode, KeyEvent event) {  
              
       if(keyCode==KeyEvent.KEYCODE_DPAD_UP)//放大
           zoomControler+=10;  
            
       if(keyCode==KeyEvent.KEYCODE_DPAD_DOWN) //缩小
           zoomControler-=10;  
            
       if(zoomControler<10)  
            zoomControler=10;  
              
        invalidate();  
       return true;  
   }
}

 

转载地址：http:www.cnblogs.com/hanyonglu/archive/2012/02/11/2346273.html