Address suggestions

wgpu/src/renderer/widget/scrollable.rs

@@ -1,72 +1,34 @@
 use crate::{Primitive, Renderer};
-use iced_native::{
-    scrollable, Background, MouseCursor, Point, Rectangle, ScrollbarGrab,
-    Vector,
-};
+use iced_native::{scrollable, Background, MouseCursor, Rectangle, Vector};
 
 const SCROLLBAR_WIDTH: u16 = 10;
 const SCROLLBAR_MARGIN: u16 = 2;
 
-fn background_bounds(bounds: Rectangle) -> Rectangle {
-    Rectangle {
-        x: bounds.x + bounds.width
-            - f32::from(SCROLLBAR_WIDTH + 2 * SCROLLBAR_MARGIN),
-        y: bounds.y,
-        width: f32::from(SCROLLBAR_WIDTH + 2 * SCROLLBAR_MARGIN),
-        height: bounds.height,
-    }
-}
-
-fn scroller_bounds(
-    bounds: Rectangle,
-    content_bounds: Rectangle,
-    background_bounds: Rectangle,
-    offset: u32,
-) -> Rectangle {
-    let ratio = bounds.height / content_bounds.height;
-    let scrollbar_height = bounds.height * ratio;
-    let y_offset = offset as f32 * ratio;
-
-    Rectangle {
-        x: background_bounds.x + f32::from(SCROLLBAR_MARGIN),
-        y: background_bounds.y + y_offset,
-        width: background_bounds.width - f32::from(2 * SCROLLBAR_MARGIN),
-        height: scrollbar_height,
-    }
-}
-
 impl scrollable::Renderer for Renderer {
-    fn scrollbar_bounds(
-        &self,
-        bounds: Rectangle,
-        content_bounds: Rectangle,
-        offset: u32,
-    ) -> (Rectangle, Rectangle) {
-        let background_bounds = background_bounds(bounds);
-        let scroller_bounds =
-            scroller_bounds(bounds, content_bounds, background_bounds, offset);
-
-        (background_bounds, scroller_bounds)
+    fn scrollbar_bounds(bounds: Rectangle) -> Rectangle {
+        Rectangle {
+            x: bounds.x + bounds.width
+                - f32::from(SCROLLBAR_WIDTH + 2 * SCROLLBAR_MARGIN),
+            y: bounds.y,
+            width: f32::from(SCROLLBAR_WIDTH + 2 * SCROLLBAR_MARGIN),
+            height: bounds.height,
+        }
     }
 
-    fn scrollbar_grab(
-        &self,
+    fn scroller_bounds(
         bounds: Rectangle,
         content_bounds: Rectangle,
-        background_bounds: Rectangle,
-        scroller_bounds: Rectangle,
-        cursor_position: Point,
-    ) -> Option<ScrollbarGrab> {
-        if content_bounds.height > bounds.height
-            && background_bounds.contains(cursor_position)
-        {
-            Some(if scroller_bounds.contains(cursor_position) {
-                ScrollbarGrab::Scroller
-            } else {
-                ScrollbarGrab::Background
-            })
-        } else {
-            None
+        scrollbar_bounds: Rectangle,
+        offset: u32,
+    ) -> Rectangle {
+        let ratio = bounds.height / content_bounds.height;
+        let scrollbar_height = bounds.height * ratio;
+        let y_offset = offset as f32 * ratio;
+        Rectangle {
+            x: scrollbar_bounds.x + f32::from(SCROLLBAR_MARGIN),
+            y: scrollbar_bounds.y + y_offset,
+            width: scrollbar_bounds.width - f32::from(2 * SCROLLBAR_MARGIN),
+            height: scrollbar_height,
         }
     }
 
@@ -77,11 +39,12 @@ impl scrollable::Renderer for Renderer {
         content_bounds: Rectangle,
         is_mouse_over: bool,
         is_mouse_over_scrollbar: bool,
+        scrollbar_bounds: Rectangle,
+        scroller_bounds: Rectangle,
         offset: u32,
         (content, mouse_cursor): Self::Output,
     ) -> Self::Output {
         let is_content_overflowing = content_bounds.height > bounds.height;
-        let background_bounds = background_bounds(bounds);
 
         let clip = Primitive::Clip {
             bounds,
@@ -91,28 +54,21 @@ impl scrollable::Renderer for Renderer {
 
         (
             if is_content_overflowing
-                && (is_mouse_over || state.currently_grabbed())
+                && (is_mouse_over || state.is_scroller_grabbed())
             {
-                let scroller_bounds = scroller_bounds(
-                    bounds,
-                    content_bounds,
-                    background_bounds,
-                    offset,
-                );
                 let scrollbar = Primitive::Quad {
                     bounds: scroller_bounds,
                     background: Background::Color([0.0, 0.0, 0.0, 0.7].into()),
                     border_radius: 5,
                 };
 
-                if is_mouse_over_scrollbar || state.currently_grabbed() {
+                if is_mouse_over_scrollbar || state.is_scroller_grabbed() {
                     let scrollbar_background = Primitive::Quad {
                         bounds: Rectangle {
-                            x: background_bounds.x
-                                + f32::from(SCROLLBAR_MARGIN),
-                            width: background_bounds.width
+                            x: scrollbar_bounds.x + f32::from(SCROLLBAR_MARGIN),
+                            width: scrollbar_bounds.width
                                 - f32::from(2 * SCROLLBAR_MARGIN),
-                            ..background_bounds
+                            ..scrollbar_bounds
                         },
                         background: Background::Color(
                             [0.0, 0.0, 0.0, 0.3].into(),
@@ -131,7 +87,7 @@ impl scrollable::Renderer for Renderer {
             } else {
                 clip
             },
-            if is_mouse_over_scrollbar || state.currently_grabbed() {
+            if is_mouse_over_scrollbar || state.is_scroller_grabbed() {
                 MouseCursor::Idle
             } else {
                 mouse_cursor