Android 绘图 阴影制作(Shadow)

 阴影制作:包括各种形状(矩形,圆形等等),以及文字等等都能设置阴影。

阴影制作是什么原理呢?

其实很简单,你需要设置阴影的东西被看作一个主层。然后在主层下面画一个阴影层。

阴影制作涉及到一个重要函数:

public   void   setShadowLayer (float radius, float dx, float dy, int color)

radius:阴影半径

dx:X轴方向的偏移量

dy:Y轴方向的偏移量

color:阴影颜色

 
注意:如果半径被设置为0,意思就是去掉阴影。
 
具体实现:
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package xiaosi.textShadow;
 
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.View;
 
public class TextShadowActivity extends Activity
{
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(new drawCanvas(this));
    }
 
    class drawCanvas extends View
    {
        private Bitmap  bitmap = null;
        public drawCanvas(Context context)
        {
            super(context);
            bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.i_skinprocess);
        }
 
        @Override
        protected void onDraw(Canvas canvas)
        {
            super.onDraw(canvas);
            // 建立Paint 物件
            Paint paint1 = new Paint();
            // 设定颜色
            paint1.setColor(0xFFFFFF00);
            // 设定阴影(柔边, X 轴位移, Y 轴位移, 阴影颜色)
            paint1.setShadowLayer(5, 3, 3, 0xFFFF00FF);
            // 实心矩形& 其阴影
            canvas.drawText("我很爱你", 20,40,paint1);
            Paint paint2 = new Paint();
            paint2.setColor(Color.GREEN);
            paint2.setShadowLayer(10, 5, 2, Color.YELLOW);
            canvas.drawText("你真傻", 20,60,paint2);
             
            Paint paint3 = new Paint();
            paint3.setColor(Color.RED);
            paint3.setShadowLayer(30, 5, 2, Color.GREEN);
            canvas.drawCircle(50, 130,30, paint3);
             
            Paint paint4 = new Paint();
            paint4.setShadowLayer(5, 8, 7, Color.DKGRAY);
            canvas.drawBitmap(bitmap, 50, 200, paint4);
        }
    }
}
原文地址:https://www.cnblogs.com/olvo/p/2469789.html