[Lazarus] Completely solve the GTK trouble

[Michael Van Canneyt]

On Tue, 14 Apr 2020, zeljko via lazarus wrote:

> On 4/14/20 10:07 AM, jiaxing ruan via lazarus wrote:
>> Do you need tester? I can help with testing. But anything needs more 
>> knowledge I afraid I can't.
>> 
>> Anyway, did we at any time found it's tired to catch up with GTK? May be 
>> we could keep the current GTK3 interface. But my suggestion also deal 
>> with GTK4, GTK5... One IUP interface, we could choose the appropriate 
>> GTK version. IUP currently supports both GTK2 and GTK3 and the API still 
>> the same. What I appreciate IUP is it focuses on a stable API. As I 
>> said, programs written for IUP 3.15 still compile and run fine with IUP 
>> 3.27. Investing on an IUP interface rather than GTK4, GTK5... interface 
>> is the most reasonable way to go.
>
> Never heard about IUP, but maybe we can get ideas for various gtk3 
> implementations from IUP. Maybe you should provide direct link to IUP 
> library, not to your h2pas conversion.

See
http://webserver2.tecgraf.puc-rio.br/iup/

I looked into it. 
Seems to me that a small OOP wrapper around the iup headers is a good idea.
The LUA bindings add some nice ideas, it looks like what we know as properties.

What does worry me in this widgetset is that there are 2 things missing:
1. a canvas for regular controls. There is a canvas, but is a separate control,
   and I'm not 100% sure whether that is a requirement for a LCL widgetset.
2. No absolute positioning, which does not go well with the LCL. You need to
use existing layouters.

So for these reasons I am not yet sure it's a viable candidate for a new widgetset.
Given that and the fact it adds it adds an additional layer, 
I would definitely not let it replace the existing GTK2/GTK3 interfaces.

Michael.


Michael.