Design of an immediate graphical user interface api with managed layouts
Terms:
1. Canvas - a drawing area with a managed layout
User stories
1. I would like to call UI-rendering functions without specifying dimensions and locations
2. I would like to call custom UI-rendering functions while specifying dimensions and locations
Story 2 needs a way to get a proper starting location or a bounding box If 1 is in place.
Consider the single method Layout interface:
type Layout interface {
// Advances the layout and returns a starting point
// for an element based on the last ending point.
Next(Point) Point
}
Story 1 necessitates that library-aware UI-rendering functions acquire their starting locations
on their own. This allows for the following two approaches (more are possible of course)
* Store the ending point of the last element. New calls can get it and pass it to the layout
+ does not advance the layout unless required, saving cpu
* Store the next starting point by calling Next() at the end of the element drawing routine.
The next drawing can continue from it.
- advancing the layout costs cpu
- the user might want an out of layer render