Use of a FLTK window as a SSD

[CyprinusCarpio]

Hey! Great project you've got going. I just found out about it today.

I'm brainstorming a new compositor, and I want to try using the FLTK widget toolkit to make the SSD. The idea is to use a single FLTK window as the entire SSD, and leverage FLTK event system and drawing. Looking at the LouvreTemplate, I see that the SSD class has several members derived from LView. Another class derived from LView is the LSurfaceView, which apparently allows to display a whole window. And that's where my idea comes from. Why not use a FLTK window as the SSD? Sort of like a reparenting X window manager, but without the reparenting - the SSD would simply be behind the window. The main problem I see is how to make a normal FLTK window into a LSurface. FLTK provides a way to get a wl_surface from it's windows, as described here.

My question is, is that enough to "bridge the gap" between Louvre and FLTK, and use a FLTK window as SSD?

Thanks for your time.

[ehopperdietzel]

Hi, if you want to use v2, you could try rendering surfaces purely with FLTK first, just to check whether it works:

• Create an empty project.
• Override only the LOutput class and its initializeGL() and paintGL() methods.
• Within paintGL(), render each LSurface texture, back to front (without LPainter, this is the default imp).

Since you won’t be using LPainter or the built-in scene utilities, you’ll need to handle output, surface, and viewporter transforms yourself. To keep things simple, you can start by testing on a single output with a scale factor of 1 to avoid related issues.

Another option is to try Louvre v3 (WIP). There’s an example called cz-crystals that uses Kay, a toolkit I’m working on that lets you create custom widgets, use Skia, and so on.

To try it out:

• Install Yoga 3.2.1
• Build and install The Cuarzo Framework (which includes Louvre, Skia and all required subprojects).

[CyprinusCarpio]

Thanks for the answer. This is a bit different than I expected. The problem isn't so much in rendering, as FLTK can easily render to a buffer that could be then used by Louvre. The rendering and user interaction would be handled by FLTK, which implements required Wayland protocols itself. I plan to make a SSD class similar to this, but with a single LSurfaceView that represents a FLTK window, to serve as the decoration. Is it possible to accomplish this?

[ehopperdietzel]

But it implements Wayland protocols from the client side I suppose, so I am not sure if it makes sense to use it from the compositor side. Maybe it has an offscreen backend and you could manually feed it with Louvre events?

[CyprinusCarpio]

Yes, this is by far the easiest way to implement this. But I also plan to use FLTK popup menus, and those need to have a proper FLTK parent window. That's why I'm trying to make a actual FLTK window into a SSD. Another option I just came up with is to do drawing and events like you described, and create a 1x1 FLTK borderless toplevel window, position it server-side and use it as the parent for popup windows.