WIP: Add middle mouse button emulation setting

cosmic-settings/src/pages/input/mod.rs

@@ -23,6 +23,7 @@ pub enum Message {
     DisableWhileTyping(bool, bool),
     PrimaryButtonSelected(cosmic::widget::segmented_button::Entity, bool),
     SetAcceleration(bool, bool),
+    SetMiddleButtonEmulation(bool, bool),
     SetMouseSpeed(f64, bool),
     SetNaturalScroll(bool, bool),
     SetSecondaryClickBehavior(Option<ClickMethod>, bool),
@@ -123,6 +124,12 @@ impl Page {
                 });
             }
 
+            Message::SetMiddleButtonEmulation(enabled, touchpad) => {
+                self.update_input(touchpad, |conf| {
+                    conf.middle_button_emulation = Some(enabled);
+                });
+            },
+
             Message::SetNaturalScroll(enabled, touchpad) => self.update_input(touchpad, |x| {
                 x.scroll_config
                     .get_or_insert(ScrollConfig::default())

cosmic-settings/src/pages/input/mouse.rs

@@ -54,6 +54,8 @@ fn mouse() -> Section<crate::pages::Message> {
     let mouse_speed = descriptions.insert(fl!("mouse", "speed"));
     let primary_button = descriptions.insert(fl!("primary-button"));
     let acceleration_desc = descriptions.insert(fl!("acceleration-desc"));
+    let middle_button_emulation = descriptions.insert(fl!("middle-button-emulation"));
+    let middle_button_emulation_desc = descriptions.insert(fl!("middle-button-emulation-desc"));
 
     Section::default()
         .descriptions(descriptions)
@@ -110,6 +112,17 @@ fn mouse() -> Section<crate::pages::Message> {
                             |x| Message::SetAcceleration(x, false),
                         ),
                 )
+                .add(
+                    settings::item::builder(&descriptions[middle_button_emulation])
+                        .description(&descriptions[middle_button_emulation_desc])
+                        .toggler(
+                            input
+                                .input_default
+                                .middle_button_emulation
+                                .unwrap_or(false),
+                            |x| Message::SetMiddleButtonEmulation(x, false),
+                        ),
+                )
                 .apply(Element::from)
                 .map(crate::pages::Message::Input)
         })

cosmic-settings/src/pages/input/touchpad.rs

@@ -154,6 +154,8 @@ fn click_behavior() -> Section<crate::pages::Message> {
     let button_areas = descriptions.insert(fl!("click-behavior", "button-areas"));
     let tap_to_click = descriptions.insert(fl!("tap-to-click"));
     let _tap_to_click_desc = descriptions.insert(fl!("tap-to-click", "desc"));
+    let middle_button_emulation = descriptions.insert(fl!("middle-button-emulation"));
+    let middle_button_emulation_desc = descriptions.insert(fl!("middle-button-emulation-desc"));
 
     Section::default()
         .title(fl!("click-behavior"))
@@ -197,6 +199,16 @@ fn click_behavior() -> Section<crate::pages::Message> {
                         Message::TapToClick,
                     ),
                 )
+                .add(
+                    settings::item::builder(&descriptions[middle_button_emulation])
+                        .description(&descriptions[middle_button_emulation_desc])
+                        .toggler(
+                            page.input_touchpad
+                                .middle_button_emulation
+                                .unwrap_or(false),
+                            |x| Message::SetMiddleButtonEmulation(x, false),
+                        ),
+                )
                 .apply(Element::from)
                 .map(crate::pages::Message::Input)
         })

i18n/en/cosmic_settings.ftl

@@ -530,6 +530,9 @@ disable-while-typing = Disable while typing
 input-devices = Input Devices
     .desc = Input Devices
 
+middle-button-emulation = Enable middle button emulation
+middle-button-emulation-desc = Emulates a middle button click when pressing the left and right buttons simultaneously.
+
 primary-button = Primary button
     .desc = Sets the order of physical buttons.
     .left = Left