Androidx學習筆記（73）--- 在內存中創建圖片的副本

public class MainActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        //這個對象是隻讀的
        Bitmap bmSrc = BitmapFactory.decodeFile("sdcard/photo3.jpg");
        
        //創建圖片副本
        //1.在內存中創建一個與原圖一模一樣大小的bitmap對象，創建與原圖大小一致的白紙
        Bitmap bmCopy = Bitmap.createBitmap(bmSrc.getWidth(), bmSrc.getHeight(), bmSrc.getConfig());
        
        //2.創建畫筆對象
        Paint paint = new Paint();
        
        //3.創建畫板對象，把白紙鋪在畫板上
        Canvas canvas = new Canvas(bmCopy);
        
        //4.開始作畫，把原圖的內容繪製在白紙上
        canvas.drawBitmap(bmSrc, new Matrix(), 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);
    }
 
}