[refactor] use "fg_" prefix in WidgetStyle

egui/src/containers/collapsing_header.rs

@@ -105,7 +105,7 @@ impl State {
 
 /// Paint the arrow icon that indicated if the region is open or not
 pub fn paint_icon(ui: &mut Ui, openness: f32, response: &Response) {
-    let stroke = ui.style().interact(response).stroke;
+    let stroke = ui.style().interact(response).fg_stroke;
 
     let rect = response.rect;
 
@@ -224,7 +224,7 @@ impl CollapsingHeader {
             text_pos,
             galley,
             label.text_style_or_default(ui.style()),
-            ui.style().interact(&response).stroke.color,
+            ui.style().interact(&response).text_color(),
         );
 
         painter.set(

egui/src/containers/resize.rs

@@ -270,7 +270,7 @@ impl Resize {
 use crate::paint::Stroke;
 
 pub fn paint_resize_corner(ui: &mut Ui, response: &Response) {
-    let stroke = ui.style().interact(response).stroke;
+    let stroke = ui.style().interact(response).fg_stroke;
     paint_resize_corner_with_style(ui, &response.rect, stroke);
 }
 

egui/src/containers/scroll_area.rs

@@ -237,7 +237,7 @@ impl Prepared {
             }
 
             let style = ui.style();
-            let handle_fill = style.interact(&response).main_fill;
+            let handle_fill = style.interact(&response).fg_fill;
             let handle_stroke = style.interact(&response).bg_stroke;
 
             ui.painter().add(paint::PaintCmd::Rect {

egui/src/containers/window.rs

@@ -711,7 +711,7 @@ fn close_button(ui: &mut Ui, rect: Rect) -> Response {
     let response = ui.interact(rect, close_id, Sense::click());
     ui.expand_to_include_child(response.rect);
 
-    let stroke = ui.style().interact(&response).stroke;
+    let stroke = ui.style().interact(&response).fg_stroke;
     ui.painter()
         .line_segment([rect.left_top(), rect.right_bottom()], stroke);
     ui.painter()

egui/src/demos/toggle_switch.rs

@@ -27,7 +27,7 @@ pub fn toggle(ui: &mut Ui, on: &mut bool) -> Response {
     // We can follow the standard style theme by asking
     // "how should something that is being interacted with be painted?".
     // This gives us visual style change when the user hovers and clicks on the widget.
-    let style = ui.style().interact(&response);
+    let visuals = ui.style().interact(&response);
     let off_color = Rgba::new(0.0, 0.0, 0.0, 0.0);
     let on_color = Rgba::new(0.0, 0.5, 0.0, 0.5);
     // All coordinates are in screen coordinates (not relative)
@@ -37,15 +37,15 @@ pub fn toggle(ui: &mut Ui, on: &mut bool) -> Response {
         rect,
         corner_radius: radius,
         fill: lerp(off_color..=on_color, how_on).into(),
-        stroke: style.bg_stroke,
+        stroke: visuals.bg_stroke,
     });
     // Animate the circle from left to right:
     let circle_x = lerp((rect.left() + radius)..=(rect.right() - radius), how_on);
     ui.painter().add(PaintCmd::Circle {
         center: pos2(circle_x, rect.center().y),
         radius: 0.75 * radius,
-        fill: style.main_fill,
-        stroke: style.stroke,
+        fill: visuals.fg_fill,
+        stroke: visuals.fg_stroke,
     });
 
     // All done! Return the response so the user can check what happened

egui/src/menu.rs

@@ -108,7 +108,7 @@ fn menu_impl<'c>(
     let mut button = Button::new(title);
 
     if bar_state.open_menu == Some(menu_id) {
-        button = button.fill(Some(ui.style().visuals.interacted.active.main_fill));
+        button = button.fill(Some(ui.style().visuals.interacted.active.fg_fill));
     }
 
     let button_response = ui.add(button);

egui/src/style.rs

@@ -148,6 +148,7 @@ impl Interacted {
     }
 }
 
+/// bg = background, fg = foreground.
 #[derive(Clone, Copy, Debug)]
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct WidgetVisuals {
@@ -163,10 +164,16 @@ pub struct WidgetVisuals {
 
     /// Fill color of the interactive part of a component (slider grab, checkbox, ...)
     /// When you need a fill.
-    pub main_fill: Srgba, // TODO: just fill?
+    pub fg_fill: Srgba,
 
     /// Stroke and text color of the interactive part of a component (button text, slider grab, check-mark, ...)
-    pub stroke: Stroke,
+    pub fg_stroke: Stroke,
+}
+
+impl WidgetVisuals {
+    pub fn text_color(&self) -> Srgba {
+        self.fg_stroke.color
+    }
 }
 
 // ----------------------------------------------------------------------------
@@ -235,29 +242,29 @@ impl Default for Interacted {
                 bg_fill: Srgba::black_alpha(128),
                 bg_stroke: Stroke::new(2.0, WHITE),
                 corner_radius: 4.0,
-                main_fill: srgba(120, 120, 200, 255),
-                stroke: Stroke::new(2.0, WHITE),
+                fg_fill: srgba(120, 120, 200, 255),
+                fg_stroke: Stroke::new(2.0, WHITE),
             },
             hovered: WidgetVisuals {
                 bg_fill: Rgba::luminance_alpha(0.06, 0.5).into(),
                 bg_stroke: Stroke::new(1.0, Rgba::white_alpha(0.5)),
                 corner_radius: 4.0,
-                main_fill: srgba(100, 100, 150, 255),
-                stroke: Stroke::new(1.5, Srgba::gray(240)),
+                fg_fill: srgba(100, 100, 150, 255),
+                fg_stroke: Stroke::new(1.5, Srgba::gray(240)),
             },
             inactive: WidgetVisuals {
                 bg_fill: Rgba::luminance_alpha(0.04, 0.5).into(),
                 bg_stroke: Stroke::new(1.0, Rgba::white_alpha(0.04)),
                 corner_radius: 4.0,
-                main_fill: srgba(60, 60, 80, 255),
-                stroke: Stroke::new(0.5, Srgba::gray(200)), // Should NOT look grayed out!
+                fg_fill: srgba(60, 60, 80, 255),
+                fg_stroke: Stroke::new(0.5, Srgba::gray(200)), // Should NOT look grayed out!
             },
             disabled: WidgetVisuals {
                 bg_fill: TRANSPARENT,
                 bg_stroke: Stroke::new(0.5, Srgba::gray(70)),
                 corner_radius: 4.0,
-                main_fill: srgba(50, 50, 50, 255),
-                stroke: Stroke::new(0.5, Srgba::gray(128)), // Should look grayed out
+                fg_fill: srgba(50, 50, 50, 255),
+                fg_stroke: Stroke::new(0.5, Srgba::gray(128)), // Should look grayed out
             },
         }
     }
@@ -367,15 +374,15 @@ impl WidgetVisuals {
             bg_fill,
             bg_stroke,
             corner_radius,
-            main_fill,
-            stroke,
+            fg_fill,
+            fg_stroke,
         } = self;
 
         ui_color(ui, bg_fill, "bg_fill");
         bg_stroke.ui(ui, "bg_stroke");
         ui.add(Slider::f32(corner_radius, 0.0..=10.0).text("corner_radius"));
-        ui_color(ui, main_fill, "main_fill");
-        stroke.ui(ui, "stroke");
+        ui_color(ui, fg_fill, "fg_fill");
+        fg_stroke.ui(ui, "fg_stroke");
     }
 }
 

egui/src/widgets.rs

@@ -305,8 +305,7 @@ impl Widget for Button {
             fill,
             stroke: ui.style().interact(&response).bg_stroke,
         });
-        let stroke_color = ui.style().interact(&response).stroke.color;
-        let text_color = text_color.unwrap_or(stroke_color);
+        let text_color = text_color.unwrap_or_else(|| ui.style().interact(&response).text_color());
         ui.painter()
             .galley(text_cursor, galley, text_style, text_color);
         response
@@ -364,6 +363,7 @@ impl<'a> Widget for Checkbox<'a> {
             *checked = !*checked;
         }
 
+        let visuals = ui.style().interact(&response);
         let text_cursor = pos2(
             response.rect.min.x + button_padding.x + icon_width,
             response.rect.center().y - 0.5 * galley.size.y,
@@ -371,13 +371,11 @@ impl<'a> Widget for Checkbox<'a> {
         let (small_icon_rect, big_icon_rect) = ui.style().spacing.icon_rectangles(response.rect);
         ui.painter().add(PaintCmd::Rect {
             rect: big_icon_rect,
-            corner_radius: ui.style().interact(&response).corner_radius,
-            fill: ui.style().interact(&response).bg_fill,
-            stroke: ui.style().interact(&response).bg_stroke,
+            corner_radius: visuals.corner_radius,
+            fill: visuals.bg_fill,
+            stroke: visuals.bg_stroke,
         });
 
-        let stroke = ui.style().interact(&response).stroke;
-
         if *checked {
             ui.painter().add(PaintCmd::Path {
                 points: vec![
@@ -386,12 +384,12 @@ impl<'a> Widget for Checkbox<'a> {
                     pos2(small_icon_rect.right(), small_icon_rect.top()),
                 ],
                 closed: false,
-                stroke,
                 fill: Default::default(),
+                stroke: visuals.fg_stroke,
             });
         }
 
-        let text_color = text_color.unwrap_or(stroke.color);
+        let text_color = text_color.unwrap_or(visuals.text_color());
         ui.painter()
             .galley(text_cursor, galley, text_style, text_color);
         response
@@ -449,8 +447,7 @@ impl Widget for RadioButton {
             response.rect.center().y - 0.5 * galley.size.y,
         );
 
-        let bg_fill = ui.style().interact(&response).bg_fill;
-        let stroke_color = ui.style().interact(&response).stroke.color;
+        let visuals = ui.style().interact(&response);
 
         let (small_icon_rect, big_icon_rect) = ui.style().spacing.icon_rectangles(response.rect);
 
@@ -459,20 +456,22 @@ impl Widget for RadioButton {
         painter.add(PaintCmd::Circle {
             center: big_icon_rect.center(),
             radius: big_icon_rect.width() / 2.0,
-            fill: bg_fill,
-            stroke: ui.style().interact(&response).bg_stroke,
+            fill: visuals.bg_fill,
+            stroke: visuals.bg_stroke,
         });
 
         if checked {
             painter.add(PaintCmd::Circle {
                 center: small_icon_rect.center(),
                 radius: small_icon_rect.width() / 3.0,
-                fill: stroke_color,
+                fill: visuals.fg_stroke.color, // Intentional to use stroke and not fill
                 stroke: Default::default(),
+                // fill: visuals.fg_fill,
+                // stroke: visuals.fg_stroke,
             });
         }
 
-        let text_color = text_color.unwrap_or(stroke_color);
+        let text_color = text_color.unwrap_or_else(|| visuals.text_color());
         painter.galley(text_cursor, galley, text_style, text_color);
         response
     }

egui/src/widgets/slider.rs

@@ -185,8 +185,8 @@ impl<'a> Slider<'a> {
             ui.painter().add(PaintCmd::Circle {
                 center: pos2(marker_center_x, rail_rect.center().y),
                 radius: handle_radius(rect),
-                fill: ui.style().interact(response).main_fill,
-                stroke: ui.style().interact(response).stroke,
+                fill: ui.style().interact(response).fg_fill,
+                stroke: ui.style().interact(response).fg_stroke,
             });
         }
     }

egui/src/widgets/text_edit.rs

@@ -209,7 +209,7 @@ impl<'t> Widget for TextEdit<'t> {
             }
         }
 
-        let text_color = text_color.unwrap_or_else(|| ui.style().interact(&response).stroke.color);
+        let text_color = text_color.unwrap_or_else(|| ui.style().interact(&response).text_color());
         painter.galley(response.rect.min, galley, text_style, text_color);
         ui.memory().text_edit.insert(id, state);
         response