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Re: [pygame] Surfarray question



Thanks Lenard. Your solution solves the mystery of image not coming up during render, but there is small problem with setting the alpha to max value.

I have 2 image one of which is a jpg and second one a png file. The png file has transparency in certain regions.
When I use array2d the transparency is preserved and i can see the bottom jpg file through the transparent regions of the png.
This would not be possible if i set alpha value to 255 for all pixels.

Is there a way out ?
 From what I presume all this should be automatically done when I blit / copy whether i use array2d or array3d


-Abhinav

On Thu, Oct 23, 2008 at 1:38 AM, Lenard Lindstrom <len-l@xxxxxxxxx> wrote:
Hi Abhinav,

You have found some unexpected behavior in pygame.surfarrray. blit_array is improperly named. It is a straight copy, not a true blit. And when a 3d array is copied to a 32 bit source alpha surface the per-pixel alpha is 0. The destination surface is completely transparent. The only workaround I can find is to set alpha to 255 after the blit_array() call:


      r_mysurface = storeObject.lib_get(o_id,"__render_surface")
      pygame.surfarray.blit_array(r_mysurface, r_myarray)
       pygame.surfarray.pixels_alpha(r_mysurface)[...] = 255


In Pgame 1.9 this will also work:

       r_mysurface.fill((0,0,0,255), None, pgyame.BLIT_RGBA_MAX)


I don't know if the 0 alpha is a bug or simply a peculiarity. Elsewhere in Pygame a 3-element color has an alpha of 255. But blit_array has probably set alpha to 0 since it was first implemented. It has simply gone unnoticed until now. Should it be changed?

Lenard


Abhinav Lele wrote:
Hi,

I am using surfarray to blit an image.
When i use array2d i see the image being renderer, but with array3d i dont.


I use the following code to load image :

           r_temp_surface = pygame.image.load(fpath).convert_alpha()
           salpha =  r_temp_surface.get_alpha()
           r_surface = pygame.Surface((o_w,o_h)).convert_alpha()
           pygame.transform.smoothscale(r_temp_surface,(o_w,o_h),r_surface)
           #if salpha != None:
           #    r_surface.set_alpha(salpha)
           r_array = pygame.surfarray.array3d(r_surface)
           print "New Surface Alpha: " , r_surface.get_alpha()
           storeObject.lib_set(o_id,"__render_surface",r_surface)
           storeObject.lib_set(o_id,"__render_array",r_array)



To render I use :

       r_myarray = storeObject.lib_get(o_id,"__render_array")
       r_mysurface = storeObject.lib_get(o_id,"__render_surface")
       pygame.surfarray.blit_array(r_mysurface, r_myarray)
       surface.blit  (r_mysurface,(gx,gy))



Plz help.

-Abhinav
 


--
Lenard Lindstrom
<len-l@xxxxxxxxx>




--

Gerald R. Ford  - "I know I am getting better at golf because I am hitting fewer spectators."