API design suggestion on `zune_imageprocs::composite::Composite::try_new`

[hillin]

The try_new API supports two location parameters: geometry and gravity:

 pub fn try_new(
        image: &'a Image, composite_method: CompositeMethod, geometry: Option<(usize, usize)>,
        gravity: Option<Gravity>
    ) -> Result<Self, &'static str>;

One must supply at least one of the two parameters. Otherwise an Err will be returned.

Since the Err case is almost always a careless coding issue and could be addressed in compile time, I would suggest to split this method into two APIs: try_new (with a mandatory geometry parameter - or should we call it location?), and try_new_gravity, with a mandatory gravity parameter and an optional geometry (or offset?) parameter, to make things simpler.

[etemesi254]

Hi, thanks for the suggestion, that is certainly better preferred.

I'm not sure which is more common, I.e gravity or geometry/position/location so I'd prefer if both have prefixes and we drop the try, something like new_gravity and new_position

[hillin]

Nice!

The gravity API seems redundant to me though. It's trivial for the caller to calculate the absolute location, or at least a helper function would be sufficient to do that.