Android实现图片缩放示例

时间：2022-06-01 18:43:56
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;

    }

}

镜面效果

matrix.setScale(-1, 1);
matrix.postTranslate(bitmap.getWidth(), 0);

倒影效果

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