Anti-aliasing of Android image painting and android image painting

Anti-aliasing of Android image painting and android image painting

When you draw a picture, if the image is rotated or scaled, there will always be those gorgeous sawtooth. In fact, Android comes with a solution.
Method 1: add the anti-tooth mark to the Paint. The painting object is passed as a parameter to the painting method of canvas.

Java code  

1. Paint. setAntiAlias (true );

 

Method 2: add the anti-tooth mark to the Canvas.
In some cases, painting is not used, so it is more convenient to directly add anti-aliasing to the canvas.

Java code  

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

 

The test code is as follows:

Java code  

1. Import android. content. Context;
2. Import android. graphics. Bitmap;
3. Import android. graphics. BitmapFactory;
4. Import android. graphics. Canvas;
5. Import android. graphics. Matrix;
6. Import android. graphics. Paint;
7. Import android. graphics. PaintFlagsDrawFilter;
8. Import android. view. View;
10. Public class MyView extends View {
11. Private PaintFlagsDrawFilter pfd;
12. Private Paint mPaint = new Paint ();
13. Private Matrix matrix = new Matrix ();;
14. Private Bitmap bmp;
16. Public MyView (Context context ){
17. Super (context );
18. Initialize ();
19. }
21. Private void initialize (){
22. Pfd = new PaintFlagsDrawFilter (0, Paint. ANTI_ALIAS_FLAG | Paint. FILTER_BITMAP_FLAG );
23. MPaint. setAntiAlias (true );
24. Matrix. setRotate (30 );
25. Matrix. postScale (0.5f, 0.5f );
26. Bmp = BitmapFactory. decodeResource (getResources (), R. drawable. show );
27. }
29. @ Override
30. Public void dispatchDraw (Canvas canvas ){
31. Canvas. translate (100, 0 );
32. Canvas. drawBitmap (bmp, matrix, null );
33. Canvas. translate (0,250 );
34. Canvas. drawBitmap (bmp, matrix, mPaint );
35. Canvas. setDrawFilter (pfd );
36. Canvas. translate (0,250 );
37. Canvas. drawBitmap (bmp, matrix, null );
38. }
39. }

 

Result:

 

We can see that both methods are quite effective.

Android image profiling

Difficult
 
Who can help solve this problem?

Replace the flag in the phrase "paint = new Paint (Paint. FILTER_BITMAP_FLAG)" with "ANTI_ALIAS_FLAG.