Android实现图片缩放示例

最新推荐文章于 2025-09-08 00:09:35 发布

转载最新推荐文章于 2025-09-08 00:09:35 发布 · 64 阅读

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原文链接：http://www.cnblogs.com/hyzhou/p/3447932.html

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#移动开发

本文详细介绍了如何在Android应用中利用Bitmap、Canvas、Matrix和Paint等API实现镜面和倒影效果的图像处理，通过设置Matrix的scale和postTranslate属性来实现图像缩放和位移，最终将处理后的图像展示在两个ImageView中。

package com.example.demo;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.view.Menu;
import android.widget.ImageView;

public class MainActivity extends Activity {

    private ImageView imageView01,imageView02;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageView01=(ImageView) findViewById(R.id.imageView1);
        imageView02=(ImageView) findViewById(R.id.imageView2);
        //设置imageview01
        Bitmap bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
        imageView01.setImageBitmap(bitmap);
        
        Bitmap alertBitmap=Bitmap.createBitmap(bitmap.getWidth()*2, bitmap.getHeight(), bitmap.getConfig());
        Canvas canvas=new Canvas(alertBitmap);//设置画布大小
        
        Matrix matrix=new Matrix();
        matrix.setScale(2.0f, 1.0f);
        /*
         * 
        
        matrix.setValues(new float[]{
                2.0f,0,0,
                0,1,0,
                0,0,1
        });
         */
        Paint paint=new Paint();
        canvas.drawBitmap(bitmap, matrix, paint);
        imageView02.setImageBitmap(alertBitmap);
        
        
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

}