Style tweaks (#2406)

* Note the namechange of egui::color to egui::ecolor

* Use a solid triangle for collapsing headers and windows

* Add Shadow::NONE

* Add Visuals::panel_fill, window_fill and window_stroke

* Bug fix: ComboBox::width sets the outer width of the ComboBox

* egui_extras::Table: add functions to access the `Ui` for the header/body

* ComboBox: use solid triangle

* Tweak default menu margin

* Nudge panel separator lines so they stay visible

* Update changelogs

CHANGELOG.md

@@ -25,6 +25,7 @@ NOTE: [`epaint`](crates/epaint/CHANGELOG.md), [`eframe`](crates/eframe/CHANGELOG
 * Added `Area::pivot` and `Window::pivot` which controls what part of the window to position ([#2303](https://github.com/emilk/egui/pull/2303)).
 * Added support for [thin space](https://en.wikipedia.org/wiki/Thin_space).
 * Added optional integration with [AccessKit](https://accesskit.dev/) for implementing platform accessibility APIs ([#2294](https://github.com/emilk/egui/pull/2294)).
+* Added `panel_fill`, `window_fill` and `window_stroke` to `Visuals` for your theming pleasure ([#2406](https://github.com/emilk/egui/pull/2406)).
 * Plots:
   * Allow linking plot cursors ([#1722](https://github.com/emilk/egui/pull/1722)).
   * Added `Plot::auto_bounds_x/y` and `Plot::reset` ([#2029](https://github.com/emilk/egui/pull/2029)).
@@ -36,6 +37,7 @@ NOTE: [`epaint`](crates/epaint/CHANGELOG.md), [`eframe`](crates/eframe/CHANGELOG
 * Panels always have a separator line, but no stroke on other sides. Their spacing has also changed slightly ([#2261](https://github.com/emilk/egui/pull/2261)).
 * Tooltips are only shown when mouse pointer is still ([#2263](https://github.com/emilk/egui/pull/2263)).
 * Make it slightly easier to click buttons ([#2304](https://github.com/emilk/egui/pull/2304)).
+* `egui::color` has been renamed `egui::ecolor` ([#2399](https://github.com/emilk/egui/pull/2399)).
 
 ### Fixed 🐛
 * ⚠️ BREAKING: Fix text being too small ([#2069](https://github.com/emilk/egui/pull/2069)).
@@ -52,6 +54,7 @@ NOTE: [`epaint`](crates/epaint/CHANGELOG.md), [`eframe`](crates/eframe/CHANGELOG
 * Fix bug in `plot::Line::fill` ([#2275](https://github.com/emilk/egui/pull/2275)).
 * Only emit `changed` events in `radio_value` and `selectable_value` if the value actually changed ([#2343](https://github.com/emilk/egui/pull/2343)).
 * Fixed sizing bug in `Grid` ([#2384](https://github.com/emilk/egui/pull/2384)).
+* `ComboBox::width` now correctly sets the outer width ([#2406](https://github.com/emilk/egui/pull/2406)).
 
 
 ## 0.19.0 - 2022-08-20

crates/egui/src/containers/collapsing_header.rs

@@ -311,7 +311,6 @@ impl<'ui, HeaderRet> HeaderResponse<'ui, HeaderRet> {
 /// Paint the arrow icon that indicated if the region is open or not
 pub fn paint_default_icon(ui: &mut Ui, openness: f32, response: &Response) {
     let visuals = ui.style().interact(response);
-    let stroke = visuals.fg_stroke;
 
     let rect = response.rect;
 
@@ -325,7 +324,11 @@ pub fn paint_default_icon(ui: &mut Ui, openness: f32, response: &Response) {
         *p = rect.center() + rotation * (*p - rect.center());
     }
 
-    ui.painter().add(Shape::closed_line(points, stroke));
+    ui.painter().add(Shape::convex_polygon(
+        points,
+        visuals.fg_stroke.color,
+        Stroke::NONE,
+    ));
 }
 
 /// A function that paints an icon indicating if the region is open or not

crates/egui/src/containers/combo_box.rs

@@ -77,7 +77,7 @@ impl ComboBox {
         }
     }
 
-    /// Set the width of the button and menu
+    /// Set the outer width of the button and menu.
     pub fn width(mut self, width: f32) -> Self {
         self.width = Some(width);
         self
@@ -261,15 +261,20 @@ fn combo_box_dyn<'c, R>(
             AboveOrBelow::Above
         };
 
+    let margin = ui.spacing().button_padding;
     let button_response = button_frame(ui, button_id, is_popup_open, Sense::click(), |ui| {
         // We don't want to change width when user selects something new
-        let full_minimum_width = wrap_enabled
+        let full_minimum_width = if wrap_enabled {
-            .then(|| ui.available_width() - ui.spacing().item_spacing.x * 2.0)
+            ui.available_width() - ui.spacing().item_spacing.x * 2.0
-            .unwrap_or_else(|| ui.spacing().slider_width);
+        } else {
+            ui.spacing().slider_width - 2.0 * margin.x
+        };
         let icon_size = Vec2::splat(ui.spacing().icon_width);
-        let wrap_width = wrap_enabled
+        let wrap_width = if wrap_enabled {
-            .then(|| ui.available_width() - ui.spacing().item_spacing.x - icon_size.x)
+            ui.available_width() - ui.spacing().item_spacing.x - icon_size.x
-            .unwrap_or(f32::INFINITY);
+        } else {
+            f32::INFINITY
+        };
 
         let galley =
             selected_text.into_galley(ui, Some(wrap_enabled), wrap_width, TextStyle::Button);
@@ -396,16 +401,18 @@ fn paint_default_icon(
     match above_or_below {
         AboveOrBelow::Above => {
             // Upward pointing triangle
-            painter.add(Shape::closed_line(
+            painter.add(Shape::convex_polygon(
                 vec![rect.left_bottom(), rect.right_bottom(), rect.center_top()],
-                visuals.fg_stroke,
+                visuals.fg_stroke.color,
+                Stroke::NONE,
             ));
         }
         AboveOrBelow::Below => {
             // Downward pointing triangle
-            painter.add(Shape::closed_line(
+            painter.add(Shape::convex_polygon(
                 vec![rect.left_top(), rect.right_top(), rect.center_bottom()],
-                visuals.fg_stroke,
+                visuals.fg_stroke.color,
+                Stroke::NONE,
             ));
         }
     }

crates/egui/src/containers/frame.rs

@@ -45,7 +45,7 @@ impl Frame {
     pub fn side_top_panel(style: &Style) -> Self {
         Self {
             inner_margin: Margin::symmetric(8.0, 2.0),
-            fill: style.visuals.window_fill(),
+            fill: style.visuals.panel_fill,
             ..Default::default()
         }
     }
@@ -53,7 +53,7 @@ impl Frame {
     pub fn central_panel(style: &Style) -> Self {
         Self {
             inner_margin: Margin::same(8.0),
-            fill: style.visuals.window_fill(),
+            fill: style.visuals.panel_fill,
             ..Default::default()
         }
     }

crates/egui/src/containers/panel.rs

@@ -306,7 +306,10 @@ impl SidePanel {
                 Stroke::NONE
             };
             // TODO(emilk): draw line on top of all panels in this ui when https://github.com/emilk/egui/issues/1516 is done
-            let resize_x = side.opposite().side_x(rect);
+            // In the meantime: nudge the line so its inside the panel, so it won't be covered by neighboring panel
+            // (hence the shrink).
+            let resize_x = side.opposite().side_x(rect.shrink(1.0));
+            let resize_x = ui.painter().round_to_pixel(resize_x);
             ui.painter().vline(resize_x, rect.y_range(), stroke);
         }
 
@@ -755,7 +758,10 @@ impl TopBottomPanel {
                 Stroke::NONE
             };
             // TODO(emilk): draw line on top of all panels in this ui when https://github.com/emilk/egui/issues/1516 is done
-            let resize_y = side.opposite().side_y(rect);
+            // In the meantime: nudge the line so its inside the panel, so it won't be covered by neighboring panel
+            // (hence the shrink).
+            let resize_y = side.opposite().side_y(rect.shrink(1.0));
+            let resize_y = ui.painter().round_to_pixel(resize_y);
             ui.painter().hline(rect.x_range(), resize_y, stroke);
         }
 

crates/egui/src/style.rs

@@ -360,6 +360,10 @@ impl Margin {
     pub fn right_bottom(&self) -> Vec2 {
         vec2(self.right, self.bottom)
     }
+
+    pub fn is_same(&self) -> bool {
+        self.left == self.right && self.left == self.top && self.left == self.bottom
+    }
 }
 
 impl From<f32> for Margin {
@@ -464,6 +468,11 @@ pub struct Visuals {
 
     pub window_rounding: Rounding,
     pub window_shadow: Shadow,
+    pub window_fill: Color32,
+    pub window_stroke: Stroke,
+
+    /// Panel background color
+    pub panel_fill: Color32,
 
     pub popup_shadow: Shadow,
 
@@ -495,7 +504,7 @@ impl Visuals {
     }
 
     pub fn weak_text_color(&self) -> Color32 {
-        crate::ecolor::tint_color_towards(self.text_color(), self.window_fill())
+        self.gray_out(self.text_color())
     }
 
     #[inline(always)]
@@ -506,12 +515,25 @@ impl Visuals {
     /// Window background color.
     #[inline(always)]
     pub fn window_fill(&self) -> Color32 {
-        self.widgets.noninteractive.bg_fill
+        self.window_fill
     }
 
     #[inline(always)]
     pub fn window_stroke(&self) -> Stroke {
-        self.widgets.noninteractive.bg_stroke
+        self.window_stroke
+    }
+
+    /// When fading out things, we fade the colors towards this.
+    // TODO(emilk): replace with an alpha
+    #[inline(always)]
+    pub fn fade_out_to_color(&self) -> Color32 {
+        self.widgets.noninteractive.bg_fill
+    }
+
+    /// Returned a "grayed out" version of the given color.
+    #[inline(always)]
+    pub fn gray_out(&self, color: Color32) -> Color32 {
+        crate::ecolor::tint_color_towards(color, self.fade_out_to_color())
     }
 }
 
@@ -651,7 +673,7 @@ impl Default for Spacing {
         Self {
             item_spacing: vec2(8.0, 3.0),
             window_margin: Margin::same(6.0),
-            menu_margin: Margin::same(1.0),
+            menu_margin: Margin::same(6.0),
             button_padding: vec2(4.0, 1.0),
             indent: 18.0, // match checkbox/radio-button with `button_padding.x + icon_width + icon_spacing`
             interact_size: vec2(40.0, 18.0),
@@ -694,8 +716,14 @@ impl Visuals {
             code_bg_color: Color32::from_gray(64),
             warn_fg_color: Color32::from_rgb(255, 143, 0), // orange
             error_fg_color: Color32::from_rgb(255, 0, 0),  // red
+
             window_rounding: Rounding::same(6.0),
             window_shadow: Shadow::big_dark(),
+            window_fill: Color32::from_gray(27),
+            window_stroke: Stroke::new(1.0, Color32::from_gray(60)),
+
+            panel_fill: Color32::from_gray(27),
+
             popup_shadow: Shadow::small_dark(),
             resize_corner_size: 12.0,
             text_cursor_width: 2.0,
@@ -718,7 +746,13 @@ impl Visuals {
             code_bg_color: Color32::from_gray(230),
             warn_fg_color: Color32::from_rgb(255, 100, 0), // slightly orange red. it's difficult to find a warning color that pops on bright background.
             error_fg_color: Color32::from_rgb(255, 0, 0),  // red
+
             window_shadow: Shadow::big_light(),
+            window_fill: Color32::from_gray(248),
+            window_stroke: Stroke::new(1.0, Color32::from_gray(190)),
+
+            panel_fill: Color32::from_gray(248),
+
             popup_shadow: Shadow::small_light(),
             ..Self::dark()
         }
@@ -757,8 +791,8 @@ impl Widgets {
     pub fn dark() -> Self {
         Self {
             noninteractive: WidgetVisuals {
-                bg_fill: Color32::from_gray(27), // window background
+                bg_fill: Color32::from_gray(27),
-                bg_stroke: Stroke::new(1.0, Color32::from_gray(60)), // separators, indentation lines, windows outlines
+                bg_stroke: Stroke::new(1.0, Color32::from_gray(60)), // separators, indentation lines
                 fg_stroke: Stroke::new(1.0, Color32::from_gray(140)), // normal text color
                 rounding: Rounding::same(2.0),
                 expansion: 0.0,
@@ -797,8 +831,8 @@ impl Widgets {
     pub fn light() -> Self {
         Self {
             noninteractive: WidgetVisuals {
-                bg_fill: Color32::from_gray(248), // window background - should be distinct from TextEdit background
+                bg_fill: Color32::from_gray(248),
-                bg_stroke: Stroke::new(1.0, Color32::from_gray(190)), // separators, indentation lines, windows outlines
+                bg_stroke: Stroke::new(1.0, Color32::from_gray(190)), // separators, indentation lines
                 fg_stroke: Stroke::new(1.0, Color32::from_gray(80)),  // normal text color
                 rounding: Rounding::same(2.0),
                 expansion: 0.0,
@@ -954,64 +988,8 @@ impl Spacing {
 
         ui.add(slider_vec2(item_spacing, 0.0..=20.0, "Item spacing"));
 
-        let margin_range = 0.0..=20.0;
+        margin_ui(ui, "Window margin:", window_margin);
-        ui.horizontal(|ui| {
+        margin_ui(ui, "Menu margin:", menu_margin);
-            ui.add(
-                DragValue::new(&mut window_margin.left)
-                    .clamp_range(margin_range.clone())
-                    .prefix("left: "),
-            );
-            ui.add(
-                DragValue::new(&mut window_margin.right)
-                    .clamp_range(margin_range.clone())
-                    .prefix("right: "),
-            );
-
-            ui.label("Window margins x");
-        });
-
-        ui.horizontal(|ui| {
-            ui.add(
-                DragValue::new(&mut window_margin.top)
-                    .clamp_range(margin_range.clone())
-                    .prefix("top: "),
-            );
-            ui.add(
-                DragValue::new(&mut window_margin.bottom)
-                    .clamp_range(margin_range.clone())
-                    .prefix("bottom: "),
-            );
-            ui.label("Window margins y");
-        });
-
-        ui.horizontal(|ui| {
-            ui.add(
-                DragValue::new(&mut menu_margin.left)
-                    .clamp_range(margin_range.clone())
-                    .prefix("left: "),
-            );
-            ui.add(
-                DragValue::new(&mut menu_margin.right)
-                    .clamp_range(margin_range.clone())
-                    .prefix("right: "),
-            );
-
-            ui.label("Menu margins x");
-        });
-
-        ui.horizontal(|ui| {
-            ui.add(
-                DragValue::new(&mut menu_margin.top)
-                    .clamp_range(margin_range.clone())
-                    .prefix("top: "),
-            );
-            ui.add(
-                DragValue::new(&mut menu_margin.bottom)
-                    .clamp_range(margin_range)
-                    .prefix("bottom: "),
-            );
-            ui.label("Menu margins y");
-        });
 
         ui.add(slider_vec2(button_padding, 0.0..=20.0, "Button padding"));
         ui.add(slider_vec2(interact_size, 4.0..=60.0, "Interact size"))
@@ -1079,6 +1057,55 @@ impl Spacing {
     }
 }
 
+fn margin_ui(ui: &mut Ui, text: &str, margin: &mut Margin) {
+    let margin_range = 0.0..=20.0;
+
+    ui.horizontal(|ui| {
+        ui.label(text);
+
+        let mut same = margin.is_same();
+        ui.checkbox(&mut same, "Same");
+
+        if same {
+            let mut value = margin.left;
+            ui.add(DragValue::new(&mut value).clamp_range(margin_range.clone()));
+            *margin = Margin::same(value);
+        } else {
+            if margin.is_same() {
+                // HACK: prevent collapse:
+                margin.right = margin.left + 1.0;
+                margin.bottom = margin.left + 2.0;
+                margin.top = margin.left + 3.0;
+            }
+
+            ui.add(
+                DragValue::new(&mut margin.left)
+                    .clamp_range(margin_range.clone())
+                    .prefix("L: "),
+            )
+            .on_hover_text("Left margin");
+            ui.add(
+                DragValue::new(&mut margin.right)
+                    .clamp_range(margin_range.clone())
+                    .prefix("R: "),
+            )
+            .on_hover_text("Right margin");
+            ui.add(
+                DragValue::new(&mut margin.top)
+                    .clamp_range(margin_range.clone())
+                    .prefix("T: "),
+            )
+            .on_hover_text("Top margin");
+            ui.add(
+                DragValue::new(&mut margin.bottom)
+                    .clamp_range(margin_range)
+                    .prefix("B: "),
+            )
+            .on_hover_text("Bottom margin");
+        }
+    });
+}
+
 impl Interaction {
     pub fn ui(&mut self, ui: &mut crate::Ui) {
         let Self {
@@ -1210,9 +1237,16 @@ impl Visuals {
             code_bg_color,
             warn_fg_color,
             error_fg_color,
+
             window_rounding,
             window_shadow,
+            window_fill,
+            window_stroke,
+
+            panel_fill,
+
             popup_shadow,
+
             resize_corner_size,
             text_cursor_width,
             text_cursor_preview,
@@ -1223,7 +1257,8 @@ impl Visuals {
 
         ui.collapsing("Background Colors", |ui| {
             ui_color(ui, &mut widgets.inactive.bg_fill, "Buttons");
-            ui_color(ui, &mut widgets.noninteractive.bg_fill, "Windows");
+            ui_color(ui, window_fill, "Windows");
+            ui_color(ui, panel_fill, "Panels");
             ui_color(ui, faint_bg_color, "Faint accent").on_hover_text(
                 "Used for faint accentuation of interactive things, like striped grids.",
             );
@@ -1233,8 +1268,8 @@ impl Visuals {
 
         ui.collapsing("Window", |ui| {
             // Common shortcuts
-            ui_color(ui, &mut widgets.noninteractive.bg_fill, "Fill");
+            ui_color(ui, window_fill, "Fill");
-            stroke_ui(ui, &mut widgets.noninteractive.bg_stroke, "Outline");
+            stroke_ui(ui, window_stroke, "Outline");
 
             rounding_ui(ui, window_rounding);
 

crates/egui/src/ui.rs

@@ -239,7 +239,7 @@ impl Ui {
         self.enabled &= enabled;
         if !self.enabled && self.is_visible() {
             self.painter
-                .set_fade_to_color(Some(self.visuals().window_fill()));
+                .set_fade_to_color(Some(self.visuals().fade_out_to_color()));
         }
     }
 

crates/egui/src/widgets/plot/legend.rs

@@ -239,7 +239,7 @@ impl Widget for &mut LegendWidget {
                 let background_frame = Frame {
                     inner_margin: vec2(8.0, 4.0).into(),
                     rounding: ui.style().visuals.window_rounding,
-                    shadow: epaint::Shadow::default(),
+                    shadow: epaint::Shadow::NONE,
                     fill: ui.style().visuals.extreme_bg_color,
                     stroke: ui.style().visuals.window_stroke(),
                     ..Default::default()

crates/egui_demo_app/src/wrap_app.rs

@@ -176,7 +176,7 @@ impl eframe::App for WrapApp {
     }
 
     fn clear_color(&self, visuals: &egui::Visuals) -> egui::Rgba {
-        visuals.window_fill().into()
+        visuals.panel_fill.into()
     }
 
     fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {

crates/egui_demo_lib/src/demo/drag_and_drop.rs

@@ -58,9 +58,8 @@ pub fn drop_target<R>(
     let mut fill = style.bg_fill;
     let mut stroke = style.bg_stroke;
     if is_being_dragged && !can_accept_what_is_being_dragged {
-        // gray out:
+        fill = ui.visuals().gray_out(fill);
-        fill = ecolor::tint_color_towards(fill, ui.visuals().window_fill());
+        stroke.color = ui.visuals().gray_out(stroke.color);
-        stroke.color = ecolor::tint_color_towards(stroke.color, ui.visuals().window_fill());
     }
 
     ui.painter().set(

crates/egui_extras/src/table.rs

@@ -516,6 +516,13 @@ pub struct Table<'a> {
 }
 
 impl<'a> Table<'a> {
+    /// Access the contained [`egui::Ui`].
+    ///
+    /// You can use this to e.g. modify the [`egui::Style`] with [`egui::Ui::style_mut`].
+    pub fn ui_mut(&mut self) -> &mut egui::Ui {
+        self.ui
+    }
+
     /// Create table body after adding a header row
     pub fn body<F>(self, add_body_contents: F)
     where
@@ -724,6 +731,13 @@ pub struct TableBody<'a> {
 }
 
 impl<'a> TableBody<'a> {
+    /// Access the contained [`egui::Ui`].
+    ///
+    /// You can use this to e.g. modify the [`egui::Style`] with [`egui::Ui::style_mut`].
+    pub fn ui_mut(&mut self) -> &mut egui::Ui {
+        self.layout.ui
+    }
+
     /// Where in screen-space is the table body?
     pub fn max_rect(&self) -> Rect {
         self.layout

crates/epaint/src/shadow.rs

@@ -14,6 +14,11 @@ pub struct Shadow {
 }
 
 impl Shadow {
+    pub const NONE: Self = Self {
+        extrusion: 0.0,
+        color: Color32::TRANSPARENT,
+    };
+
     /// Tooltips, menus, …, for dark mode.
     pub fn small_dark() -> Self {
         Self {