如何旋转合并 bitmap 而不会在侧面被切割/修剪

Question

I merge bitmap using this code

    Bitmap bitmapMerged = 
    Bitmap.createBitmap(
    w, h, bitmapOriginal.getConfig()); 

    Canvas canvasMerged = new  
    Canvas(bitmapMerged);            
    canvasMerged.drawBitmap
    (bitmapOriginal, 0, 0, null);

    canvasMerged.drawBitmap
    (bitmapSecond, 
    bitmapOriginal.getWidth(), 0, null);                 
    image3.setImageBitmap
   (bitmapMerged);

After I successfully merge the two bitmap (bitmapOriginal and bitmapSecond)

I want to rotate bitmapOriginal but after using this code

     Matrix matrix = new Matrix(); 
    matrix.postRotate(20); 

     Bitmap scaledBitmap =  
    Bitmap.createScaledBitmap
    (bitmapOriginal, 
    bitmapOriginal.getWidth(), h, true); 
    Bitmap bitmapOriginal = 
    Bitmap.createBitmap
   (scaledBitmap, 0, 0, 
    scaledBitmap.getWidth(), 
   scaledBitmap.getHeight(), matrix, 
   true); 

bitmapOriginal rotated but it it side is cutted

How to fix this

By the way the value of w, and h.

  int w = bitmapOriginal.getWidth() + 
  bitmapSecond.getWidth();
  int h;
  if
 (bitmapOriginal.getHeight() >= 
 bitmapSecond.getHeight())
 { 
 h = bitmapOriginal.getHeight();
 }
 else
 { 
    h = bitmapSecond.getHeight(); 
 
 

 
    } 

Answer 1

I believe your issue is with the value you are using for w and h.

You are setting the width to the sum of the widths of both bitmaps, and the height to the largest height of the two bitmaps. But if you think about it, if you rotate a rectangle, it's corners will be outside of where the original border was. See this image for a visual of what I mean.

The solution for you would be to use larger values of w and h, to allow more space for the rotated corners.