CODEWITHSUNDEEP
pythonpygame
Yuval Amir
Yuval Amir

Reputation: 203

Using the pygame function pygame.pixelcopy.surface_to_array()

I've been sitting on this for a while now but the documentation is really confusing and has no examples.

I'm trying to store the rgb values of every pixel in a surface. I've tried the following code:

original_pixels = numpy.zeros((wn_width, wn_height, 3))
pygame.pixelcopy.surface_to_array(original_pixels, wn, 'P')

but it throws the error ValueError: Unsupport array item type.

From the documentation:

surface_to_array(array, surface, kind='P', opaque=255, clear=0) -> None The surface_to_array function copies pixels from a Surface object to a 2D or 3D array. Depending on argument kind and the target array dimension, a copy may be raw pixel value, RGB, a color component slice, or colorkey alpha transparency value. Recognized kind values are the single character codes 'P', 'R', 'G', 'B', 'A', and 'C'. Kind codes are case insensitive, so 'p' is equivalent to 'P'. The first two dimensions of the target must be the surface size (w, h).

The default 'P' kind code does a direct raw integer pixel (mapped) value copy to a 2D array and a 'RGB' pixel component (unmapped) copy to a 3D array having shape (w, h, 3). For an 8 bit colormap surface this means the table index is copied to a 2D array, not the table value itself. A 2D array's item size must be at least as large as the surface's pixel byte size. The item size of a 3D array must be at least one byte.

For the 'R', 'G', 'B', and 'A' copy kinds a single color component of the unmapped surface pixels are copied to the target 2D array. For kind 'A' and surfaces with source alpha (the surface was created with the SRCALPHA flag), has a colorkey (set with Surface.set_colorkey()), or has a blanket alpha (set with Surface.set_alpha()) then the alpha values are those expected for a SDL surface. If a surface has no explicit alpha value, then the target array is filled with the value of the optional opaque surface_to_array argument (default 255: not transparent).

Copy kind 'C' is a special case for alpha copy of a source surface with colorkey. Unlike the 'A' color component copy, the clear argument value is used for colorkey matches, opaque otherwise. By default, a match has alpha 0 (totally transparent), while everything else is alpha 255 (totally opaque). It is a more general implementation of pygame.surfarray.array_colorkey()Copy the colorkey values into a 2d array.

Specific to surface_to_array, a ValueError is raised for target arrays with incorrect shape or item size. A TypeError is raised for an incorrect kind code. Surface specific problems, such as locking, raise a pygame.error.

By the way if you can just recommend a different approach to achieve the same goal it's all good.

Upvotes: 1

Views: 214

Answers (1)

Rabbid76
Rabbid76

Reputation: 210878

Your code is almost correct, but by default numpy.zeros creates an array of floats. However, for use with pygame.pixelcopy.surface_to_array the datatype must be uint8:

original_pixels = numpy.zeros((wn_width, wn_height, 3), dtype=numpy.uint8)
pygame.pixelcopy.surface_to_array(original_pixels, wn, 'P')

Upvotes: 1

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