Hi everybody! *echo back: "Hi Dr. Nick!"*

Ahem, I'm currently writing a program *points to sig* and I need to do some image resizing so I can support multiple screen resolutions. I'm using C++ with the SDL API and I want to be able to resize a SDL_Surface object that will always be 1024x768 so it can resized to 1200x1024, 800x600, and possibly even 640x480. The bit-depth is 24bpp, but the program allows lower bpp for users who can't handle that depth. So far my googling efforts have been fruitless for I can't find anything that can help.

Someone did mention to me today on #SDL @ freenode.irc.net that the SDL_gfx library does image resizing, but it is not supported across very many platforms, has poor documentation, and I think it's kinda stupid to require users to download and install an entire library just so I can import one feature from it.

So if any of you can provide me with links or information on where I can find the following, I'd appreciate it greatly

1) Code that takes an SDL_Surface object, resizes it, and returns a new SDL_Object that is the specified height and width.

2) Free (GPL) C/C++ code for image resizing.

3) Algorithms for image resizing.

1.
and
2.

You are having the api at front of you. SDL_gfx is also a part of most distributions (eg. debian).
Want the source? "apt-get source libsdl-gfx1.2" and check the SDL_rotozoom.c.

Want an other algorithms? "apt-get source imagemagick" and check the magick/resize.c.

Still don't want to use that library as a whole? Well, don't. You are free to go and pick just that code from it for a project under GPL license.