Android-實作圖檔的簡單特效（平移、縮放、旋轉、鏡面、倒影）

效果：

布局代碼：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" 
    android:orientation="vertical"
    >

    <ImageView
        android:id="@+id/iv_src"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />
    <ImageView
        android:id="@+id/iv_copy"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />

</LinearLayout></span>
           

MainActivity.java

package com.example.cn;

import android.os.Bundle;
import android.os.Environment;
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 {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        
        String path = Environment.getExternalStorageDirectory() + "/" + "3.jpg";
        //這個對象是隻讀的
        Bitmap bmSrc = BitmapFactory.decodeFile(path);
        
        //建立圖檔副本
        //1.在記憶體中建立一個與原圖一模一樣大小的bitmap對象，建立與原圖大小一緻的白紙
        Bitmap bmCopy = Bitmap.createBitmap(bmSrc.getWidth(), bmSrc.getHeight(), bmSrc.getConfig());
        
        //2.建立畫筆對象
        Paint paint = new Paint();
        
        //3.建立畫闆對象，把白紙鋪在畫闆上
        Canvas canvas = new Canvas(bmCopy);
        
        //4.開始作畫，把原圖的内容繪制在白紙上
        Matrix mt = new Matrix();
        
        //平移
//        mt.setTranslate(20, 40);
        //縮放
        //sx：水準方向的縮放比例
        //sy：豎直方向的縮放比例
//        mt.setScale(0.5f, 0.5f);
//        mt.setScale(0.5f, 0.5f, bmCopy.getWidth() / 2, bmCopy.getHeight() / 2);
        //旋轉
//        mt.setRotate(45, bmCopy.getWidth() / 2, bmCopy.getHeight() / 2);
        
        //鏡面
        mt.setScale(-1, 1);
        mt.postTranslate(bmCopy.getWidth(), 0);
        //倒影
//        mt.setScale(1, -1);
//        mt.postTranslate(0, bmCopy.getHeight());
        canvas.drawBitmap(bmSrc, mt, paint);
        
        ImageView iv_src = (ImageView) findViewById(R.id.iv_src);
        ImageView iv_copy = (ImageView) findViewById(R.id.iv_copy);
        iv_src.setImageBitmap(bmSrc);
        iv_copy.setImageBitmap(bmCopy);
    }
    
}
</span>