Add the possibility to load an image into a pre-allocated memory buffer / surface

[Raffaello]

with a pre-allocated pixels (buffer) might be more versatile as a surface can be created from it. on the other hand from a surface it can be easily accessed to the pixel buffer...

The reason for this function would be to reuse the same surface/buffer so for e.g. in openGL can be persistently mapped and used with PBO for streaming texture from disk more efficiently. Basically it comes down to do a streamed animation.

What is missing it might be to have also a sibling function to read metadata of the image so the width,height,channels can be read and creating accordingly the surface/buffer.

this kind of feature is available in OpenImage:

• https://openimageio.readthedocs.io/en/v3.0.1.0/imageinput.html

a function to load an image from a user input buffer add some possiblity to various use cases.

[Raffaello]

I don't think it might be too much work as there are already APIs accepting a SDL_IOStream*

so for e.g. the prototype could be:

bool IMG_LoadIntoSurf_IO(SDL_IOStream *src, SDL_Surface* surf, bool closeio);

internally it could do also check that the surface is the right size or something like that.

[Raffaello]

i might also could have time to look into it implementing if it is reasonable to implement it.