This function performs a fast fill of the given rectangle with +color. If dstrect +is NULL, the whole surface will be filled with +color.
The color should be a pixel of the format used by the surface, and +can be generated by the +SDL_MapRGB or SDL_MapRGBA +functions. If the color value contains an alpha value then the +destination is simply "filled" with that alpha information, no blending +takes place.
If there is a clip rectangle set on the destination (set via +SDL_SetClipRect) then this +function will clip based on the intersection of the clip rectangle and +the dstrect rectangle and the dstrect rectangle +will be modified to represent the area actually filled.