It isnt a sprite drawing program like GraphicsGale, but rather allows you to take sprite asset parts and manipulate them to create the animation.
Correct
It doesnt use a spritepage ( but can or will support exporting th eanimation to a sprite page ).
If by "spritepage" you're referring to a sprite sheet which contains a grid of full-sprite animation frames, then you are correct. Though supporting sprite sheets inside of Spriter wouldn't be a bad idea either. I'll ask him about this. He might already be planning it
Does it recalculate light sources ? I realise that sprites dont generally tend to adjust to varying lights much, but artists can and do adjust frames to compensate for changing surfaces exposure to light.
Example : A characters leg while standing is exposed to different amounts of light than if the characters leg was extended in a kick action.
I mean would it take a characters leg and simply rotate it to the kick position, or does it actually work out light?
The tool simply rotates the images and doesn't adjust lighting on the images you've drawn. This is quite a difficult problem to solve with any 2d image without simply having the artist redraw a different version of it. In that same sense, you could make another version of the leg in shadow for use in Spriter and switch to it at the appropriate time in the animation. This is possible to do not only with lighting, but also to show various rotations of parts. For example, I may want to make a fighter character that throws a punch. If I just make a standard idle pose and rotate the arm parts, it'll look pretty weak. But if I draw a couple more pieces, such as maybe a torso piece that's rotated to show his back, the animation will seem much more natural and dynamic. Tweening is still possible when you redraw pieces. The only other way I can think of getting more dynamic lighting is to rig up Spriter textures with normal maps if you're feeling up for it.
Would this tool be usefull to a new programmer / developer who has only used a simple sprite page animation?
How hard would it be to get C++ to read and use the Spriter data ? Or would it be still usefull by simply creating the animation and then exporting the result to make a spritepage?
It certainly would be useful for some people to bake out animations as sprite sheets. If that's what you want to do, then by all means. But be aware you lose all of the benefits of having the spriter data - such as smooth keyframes, image swapping, memory savings, etc. As for implementing it into C++, I'm fairly certain that they're planning on releasing a framework for it. And if they dont, the format is easy enough that you'd be able to write your own implementation.
Oh, and does anyone know a good free ( or really cheap ) sprite drawing package like GraphicsGale, or is Gale the best cheap-skate option still ?
Graphics gale is absolutely superb for pixel art sprites. If you want something more versatile you can check out Gimp. Other than that, you'll have to put down some money. I personally prefer photoshop for my work.