feat(#2989): (optional) hover for all modules

[haug1]

A second attempt at implementing hover for all modules in a much less intrusive way.

See #3139 also (the more naive implementation which I found a similar approach had been tried and reverted).

Let me know if any additional documentation is required to get this merged. Alternatively, I think this could just be merged directly exposing the functionality for the super users immediately and then improved upon later on.

[haug1]

(Force-push removed debug log statements)

[Alexays]

Nice approach, it might be the perfect workaround to have hover effect.
I would even remove the "hover" config and enable it for everyone, as it's just a class.

[Alexays]

Can you also add it to the man?

[haug1]

Can you also add it to the man?

Thanks, I'll handle your feedback tonight when I have time!

[haug1]

Made the following changes:

• removed unnecessary include
• removed configuration option, hover signals are attached by default
• added documentation in waybar-styles man-page

[alebastr]

Might be useful: after a short dive into the GTK internals, I figured out how to make the :hover pseudo-class work:

diff --git a/src/AModule.cpp b/src/AModule.cpp
index f941ab97..a285da77 100644
--- a/src/AModule.cpp
+++ b/src/AModule.cpp
@@ -87,12 +87,16 @@ auto AModule::doAction(const std::string& name) -> void {
 }
 
 bool AModule::handleMouseEnter(GdkEventCrossing* const& e) {
-  event_box_.get_style_context()->add_class("hover");
+  if (auto* module = event_box_.get_child(); module != nullptr) {
+    module->set_state_flags(Gtk::StateFlags::STATE_FLAG_PRELIGHT);
+  }
   return true;
 }
 
 bool AModule::handleMouseLeave(GdkEventCrossing* const& e) {
-  event_box_.get_style_context()->remove_class("hover");
+  if (auto* module = event_box_.get_child(); module != nullptr) {
+    module->unset_state_flags(Gtk::StateFlags::STATE_FLAG_PRELIGHT);
+  }
   return true;
 }
 

Important part of the trick is that GtkEventBox does not propagate the state flags to the child widgets, so you have to apply the PRELIGHT (:hover) state flag directly to the module widget.

[haug1]

I could attempt @alebastr's solution if that is preferrable. It looks good to me, I don't know, maybe it's a bit more elegant.

If my understanding is correct, I think the CSS would look like this instead, which I think shouldn't be breaking any configurations out in the wild, although I guess it's more likely that some people have failed attempts at applying hover like this in their configs:

#pulseaudio:hover {
  // styles
}

[haug1]

I jumped the gun and applied those changes. I think it's much more elegantly done like this. We get the normal CSS :hover and applied on the correct GTK component. Kudos to @alebastr for digging into GTK a lot better than me! 👍

[Alexays]

🔥