Question

I am trying to load a movement map from a PNG image. In order to save memory
after I load the bitmap I do something like that.

 
 `Bitmap mapBmp = tempBmp.copy(Bitmap.Config.ALPHA_8, false);` 
 

If I draw the mapBmp I can see the map but when I use getPixel() I get
always 0 (zero).

Is there a way to retrieve ALPHA information from a bitmap other than
with getPixel() ?

Answer 1

I was able to find a nice and sort of clean way to create boundary maps. I create an ALPHA_8 bitmap from the start. I paint my boundry map with paths. Then I use the copyPixelsToBuffer() and transfer the bytes into a ByteBuffer. I use the buffer to “getPixels” from.
I think is a good solution since you can scale down or up the path() and draw the boundary map at the desired screen resolution scale and no IO + decode operations.
Bitmap.getPixel() is useless for ALPHA_8 bitmaps, it always returns 0.