gtk get actual pixel height of widget

[FoxyBrown via Digitalmars-d-learn]

On Saturday, 5 August 2017 at 15:23:15 UTC, Johnson Jones wrote:
> I am trying to set positions of widgets automatically. e.g., I 
> have a paned widget and I to set the position of the handle 
> manually based on a percentage of the window. e.g., 0.5 will 
> set the handle midway and both children will have the same 
> height. I 0.2 will set it to to 20%.
>
> [...]

Sorry, I think I was running my code before the window was 
actually being shown and I guess these values are not set until 
the actual display of the window.