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

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