加载大图片	Options options=new Options();	options.inJustDecodeBounds=true;//不加载图片，只加载文件信息	//加载图片，获取到配置信息	BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/a.jpg",options);	int width=options.outWidth;//获取到图片的真是宽度	int height=options.outHeight;//获取到图片的真是的高度	//获取到手机屏幕显示对象	Display display = getWindowManager().getDefaultDisplay();	int h = display.getHeight();//获取屏幕的高度	int w = display.getWidth();//获取到平局的宽度	//计算缩放的比率	int scale=1;	int scaley=width/w;	int scalex=height/h;	if(scalex<1 && scaley<1){			}else{		//如果缩放的宽，大于高，则安照宽的缩放比率，因为高的缩放比率小，那么按照高的缩放比率的话，宽则超出了屏幕的宽		scale=scalex>scaley?scalex:scaley;	}		options.inJustDecodeBounds=true;	options.inSampleSize=scale;//指定缩放比率	//根据配置信息，重新生成有一个bitmap对象，这就得到的是缩放之后的图片	Bitmap bitmap = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/a.jpg",options);	img.setImageBitmap(bitmap);涂鸦        1、首先加载一个图片Bitmap bitmap = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory() + "/a.jpg");	2.创建一个空的图片，bit = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(),bitmap.getConfig());	3.创建一个画布，Canvas canvas=new Canvas(bit);	4.创建一个画笔 panint paint=new Paint(); paint.setcolor(Color.red);	5.把加载的图片画到画布上 canvas.drawBitmap(bitmap)	6.在图片上设置触摸事件，根据按下和移动的位置开始画线加水印	和上面的一样，只是加了一句canvas.drawText("饿哦我到底发生", 100,100, paint);
保存图片通知相册扫描该图片	bit.compress(CompressFormat.JPEG, 100, new FileOutputStream(Environment.getExternalStorageDirectory()+"/hdksh.jpg"));	Intent intent=new Intent();	intent.setAction("android.intent.action.MEDIA_MOUNTED");	intent.setData(Uri.fromFile(new File(Environment.getExternalStorageDirectory()+"hdksh.jpg")));	sendBroadcast(intent);//发送广播，通知相册扫描
图片的旋转	Bitmap bitmap=BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/mm.jpg");	Bitmap bit = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());	Canvas canvas=new Canvas(bit);	Matrix matrix=new Matrix();	matrix.setRotate(180, bitmap.getWidth()/2, bitmap.getHeight()/2);	Paint paint=new Paint();	paint.setColor(Color.RED);	canvas.drawBitmap(bitmap, matrix, paint);	img.setImageBitmap(bit)
镜面效果	Bitmap bitmap = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory()+"/mm.jpg");	Bitmap bit = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());	Canvas canvas=new Canvas(bit);	Paint paint=new Paint();	Matrix matrix=new Matrix();	matrix.setScale(-1, 1);//反转	matrix.postTranslate(bitmap.getWidth(), 0);//移动	canvas.drawBitmap(bitmap, matrix, paint);	img.setImageBitmap(bit);