Merge pull request #2585 from dtzxporter/scrollbar-show-always-disabled

Scrollbar disabled style status to allow custom styles for always visible, but not overflowing scrollbars.

widget/src/scrollable.rs

@@ -906,14 +906,21 @@ where
                 is_vertical_scrollbar_dragged: state
                     .y_scroller_grabbed_at
                     .is_some(),
+                is_horizontal_scrollbar_disabled: scrollbars.is_x_disabled(),
+                is_vertical_scrollbar_disabled: scrollbars.is_y_disabled(),
             }
         } else if cursor_over_scrollable.is_some() {
             Status::Hovered {
                 is_horizontal_scrollbar_hovered: mouse_over_x_scrollbar,
                 is_vertical_scrollbar_hovered: mouse_over_y_scrollbar,
+                is_horizontal_scrollbar_disabled: scrollbars.is_x_disabled(),
+                is_vertical_scrollbar_disabled: scrollbars.is_y_disabled(),
             }
         } else {
-            Status::Active
+            Status::Active {
+                is_horizontal_scrollbar_disabled: scrollbars.is_x_disabled(),
+                is_vertical_scrollbar_disabled: scrollbars.is_y_disabled(),
+            }
         };
 
         if let Event::Window(window::Event::RedrawRequested(_now)) = event {
@@ -968,8 +975,13 @@ where
             _ => mouse::Cursor::Unavailable,
         };
 
-        let style = theme
-            .style(&self.class, self.last_status.unwrap_or(Status::Active));
+        let style = theme.style(
+            &self.class,
+            self.last_status.unwrap_or(Status::Active {
+                is_horizontal_scrollbar_disabled: false,
+                is_vertical_scrollbar_disabled: false,
+            }),
+        );
 
         container::draw_background(renderer, &style.container, layout.bounds());
 
@@ -1661,6 +1673,7 @@ impl Scrollbars {
                 bounds: scrollbar_bounds,
                 scroller,
                 alignment: vertical.alignment,
+                disabled: content_bounds.height <= bounds.height,
             })
         } else {
             None
@@ -1730,6 +1743,7 @@ impl Scrollbars {
                 bounds: scrollbar_bounds,
                 scroller,
                 alignment: horizontal.alignment,
+                disabled: content_bounds.width <= bounds.width,
             })
         } else {
             None
@@ -1758,6 +1772,14 @@ impl Scrollbars {
         }
     }
 
+    fn is_y_disabled(&self) -> bool {
+        self.y.map(|y| y.disabled).unwrap_or(false)
+    }
+
+    fn is_x_disabled(&self) -> bool {
+        self.x.map(|x| x.disabled).unwrap_or(false)
+    }
+
     fn grab_y_scroller(&self, cursor_position: Point) -> Option<f32> {
         let scrollbar = self.y?;
         let scroller = scrollbar.scroller?;
@@ -1804,6 +1826,7 @@ pub(super) mod internals {
         pub bounds: Rectangle,
         pub scroller: Option<Scroller>,
         pub alignment: Anchor,
+        pub disabled: bool,
     }
 
     impl Scrollbar {
@@ -1867,20 +1890,33 @@ pub(super) mod internals {
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum Status {
     /// The [`Scrollable`] can be interacted with.
-    Active,
+    Active {
+        /// Whether or not the horizontal scrollbar is disabled meaning the content isn't overflowing.
+        is_horizontal_scrollbar_disabled: bool,
+        /// Whether or not the vertical scrollbar is disabled meaning the content isn't overflowing.
+        is_vertical_scrollbar_disabled: bool,
+    },
     /// The [`Scrollable`] is being hovered.
     Hovered {
         /// Indicates if the horizontal scrollbar is being hovered.
         is_horizontal_scrollbar_hovered: bool,
         /// Indicates if the vertical scrollbar is being hovered.
         is_vertical_scrollbar_hovered: bool,
+        /// Whether or not the horizontal scrollbar is disabled meaning the content isn't overflowing.
+        is_horizontal_scrollbar_disabled: bool,
+        /// Whether or not the vertical scrollbar is disabled meaning the content isn't overflowing.
+        is_vertical_scrollbar_disabled: bool,
     },
     /// The [`Scrollable`] is being dragged.
     Dragged {
         /// Indicates if the horizontal scrollbar is being dragged.
         is_horizontal_scrollbar_dragged: bool,
         /// Indicates if the vertical scrollbar is being dragged.
         is_vertical_scrollbar_dragged: bool,
+        /// Whether or not the horizontal scrollbar is disabled meaning the content isn't overflowing.
+        is_horizontal_scrollbar_disabled: bool,
+        /// Whether or not the vertical scrollbar is disabled meaning the content isn't overflowing.
+        is_vertical_scrollbar_disabled: bool,
     },
 }
 
@@ -1958,7 +1994,7 @@ pub fn default(theme: &Theme, status: Status) -> Style {
     };
 
     match status {
-        Status::Active => Style {
+        Status::Active { .. } => Style {
             container: container::Style::default(),
             vertical_rail: scrollbar,
             horizontal_rail: scrollbar,
@@ -1967,6 +2003,7 @@ pub fn default(theme: &Theme, status: Status) -> Style {
         Status::Hovered {
             is_horizontal_scrollbar_hovered,
             is_vertical_scrollbar_hovered,
+            ..
         } => {
             let hovered_scrollbar = Rail {
                 scroller: Scroller {
@@ -1994,6 +2031,7 @@ pub fn default(theme: &Theme, status: Status) -> Style {
         Status::Dragged {
             is_horizontal_scrollbar_dragged,
             is_vertical_scrollbar_dragged,
+            ..
         } => {
             let dragged_scrollbar = Rail {
                 scroller: Scroller {