应用BitmapShader实现平铺的画布背景和椭圆形的图片

朴灿烈づ我的快乐病毒、 2022-08-19 12:16 127阅读 0赞

1、布局文件

<?xml version="1.0" encoding="utf-8"?>
    <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/frameLayout1"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical" >
       
    </FrameLayout>

2、MainActivity

public class MainActivity extends Activity {
    	
    	private int view_width;
    	private int view_height;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            FrameLayout ll = (FrameLayout)findViewById(R.id.frameLayout1);
            ll.addView(new MyView(this));
        }
        public class MyView extends View{
    		public MyView(Context context) {
    			super(context);
    			view_width = context.getResources().getDisplayMetrics().widthPixels; 		// 获取屏幕的宽度
    			view_height = context.getResources().getDisplayMetrics().heightPixels;		// 获取屏幕的高度
    		}
    		@Override
    		protected void onDraw(Canvas canvas) {
    			Paint paint = new Paint();//定义一个画笔
    			paint.setAntiAlias(true);//使用抗锯齿功能
    			Bitmap bitmap_bg = BitmapFactory.decodeResource(MainActivity.this.getResources(),
    					R.drawable.android);
    			//创建一个在水平和垂直方向都重复的BitmapShader对象
    			BitmapShader bitmapshader = new BitmapShader(bitmap_bg, TileMode.REPEAT, TileMode.REPEAT);
    			paint.setShader(bitmapshader);//设置渲染对象
    			canvas.drawRect(0, 0, view_width, view_height, paint);//绘制一个使用BitmapShader渲染的矩形
    			Bitmap bm = BitmapFactory.decodeResource(MainActivity.this.getResources(),
    					R.drawable.img02);
    			//创建一个在水平方向上重复，在垂直方向上镜像的BitmapShader对象
    			BitmapShader bs = new BitmapShader(bm, TileMode.REPEAT, TileMode.MIRROR);
    			paint.setShader(bs);//设置渲染对象
    			RectF oval = new RectF(0, 0, 280, 180);
    			canvas.translate(40, 20);//将画面在X轴上平移40像素，在Y轴上平移20像素
    			canvas.drawOval(oval, paint);//绘制一个使用BitmapShader渲染的椭圆形
    			super.onDraw(canvas);
    		}
        }
    }

![Center][]

[Center]: /images/20220731/61dabfe560ce4498992627aa71134f38.png