Lorenz Quack wrote:
Marcus von Appen wrote:
On, Fri Apr 11, 2008, Lenard Lindstrom wrote:
Lorenz Quack wrote:
[...]
The patch may have been a bit premature:
The person who initially reported this problem to me tells me that
with this fix applying changes to the pixels3d array does not change
the original surface. I guess that numpy.reshape() making a copy
does cause problems in some cases. I'm out of ideas how to go about
this...
That's peculiar.
import numpy
help(numpy.ndarray.reshape)
Help on method_descriptor:
reshape(...)
a.reshape(d1, d2, ..., dn, order='c')
Return a new array from this one. The new array must have the
same number
of elements as self. Also always returns a view or raises a
ValueError if
that is impossible.
Unless I am mistaken a view is an array that references another array.
pydoc numpy.reshape:
Help on function reshape in numpy:
numpy.reshape = reshape(a, newshape, order='C')
Returns an array containing the data of a, but with a new shape.
[...]
*Returns*:
reshaped_array : array
This will be a new view object if possible; otherwise, it will
return a copy.
Attached you'll find the second try to get rid of this issue. Can you
please test it? It (once more) works well for me :-).
Regards
Marcus
Hi Marcus,
your patch didn't work for me. But creating the array in one step rather
than rearranging it several times seems intriguing. I played around with
it a bit and now it works for me. I don't know about that mysterious
friend of mine but I'll send him the patch as well and let you know what
his results are.
The only thing that is a little strange right now is that on a 32 bit
surface the alpha channel ends up at index 0 with r,g,b at 1,2,3.
this happens because in the get_buffer() stream the order is b,g,r,a
(even though the surface.get_shifts() seems to indicate the the order is
RGB). so it is kind of hard to reorder the rgb without also reversing
the alpha channel.
let me know if you have any problems with the patch I attached.
yours
//Lorenz
Hey there,
well I did mix up the strides in the last patch. so here is my most
recent patch. Neither me nor my associate experience any of the problems
we had before with this patch. However, the issue with the alpha value
ending up on index 0 remains. It would be really sad if we would have to
reshape the array just to get the alpha value in the correct spot.
yours
//Lorenz
--- _numpysurfarray.py_bak 2008-04-11 20:40:06.000000000 +0200
+++ _numpysurfarray.py 2008-04-12 01:03:52.000000000 +0200
@@ -192,7 +192,7 @@
# RGB
end = None
if pygame.get_sdl_byteorder () == pygame.LIL_ENDIAN:
- start = 2
+ start = bpp - 1
step = -1
else:
start = 0
@@ -204,15 +204,12 @@
start = 0
step = 1
else:
- start = 2
+ start = bpp - 1
step = -1
-
- array = numpy.frombuffer (surface.get_buffer (), numpy.uint8)
- array.shape = surface.get_height (), surface.get_pitch ()
- array = array[:,:surface.get_width () * bpp]
- array = numpy.reshape (array, (surface.get_width (), surface.get_height (),
- bpp))
- array = array[:,:,start:end:step]
+ array = numpy.ndarray \
+ (shape=(surface.get_width (), surface.get_height (), bpp),
+ dtype=numpy.uint8, buffer=surface.get_buffer (),
+ offset=start, strides=(bpp, surface.get_pitch (), step))
return array
def array_alpha (surface):
