Android画图之抗锯齿paint和Canvas两种方式实例

2019-12-12 03:06:25

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在画图的时候，图片如果旋转或缩放之后，总是会出现那些华丽的锯齿。其实Android自带了解决方式。

方法一：给Paint加上抗锯齿标志。然后将Paint对象作为参数传给canvas的绘制方法。

paint.setAntiAlias(true);

方法二：给Canvas加上抗锯齿标志。

有些地方不能用paint的，就直接给canvas加抗锯齿，更方便。

复制代码代码如下:

canvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG));  

eg：

import android.content.Context; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Matrix; import android.graphics.Paint; import android.graphics.PaintFlagsDrawFilter; import android.view.View; public class MyView extends View {   private PaintFlagsDrawFilter pfd;   private Paint mPaint = new Paint();   private Matrix matrix = new Matrix();;   private Bitmap bmp;   public MyView(Context context) {     super(context);     initialize();   }   private void initialize() {     pfd = new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG|Paint.FILTER_BITMAP_FLAG);        mPaint.setAntiAlias(true);     matrix.setRotate(30);     matrix.postScale(0.5f, 0.5f);     bmp = BitmapFactory.decodeResource(getResources(), R.drawable.show);   }   @Override   public void dispatchDraw(Canvas canvas) {     canvas.translate(100, 0);     canvas.drawBitmap(bmp, matrix, null);     canvas.translate(0, 250);     canvas.drawBitmap(bmp, matrix, mPaint);     canvas.setDrawFilter(pfd);     canvas.translate(0, 250);     canvas.drawBitmap(bmp, matrix, null);   } }

下图是效果：