Per-corner rounding of rectangles

egui/src/containers/frame.rs

@@ -9,7 +9,7 @@ use epaint::*;
 pub struct Frame {
     /// On each side
     pub margin: Vec2,
-    pub corner_radius: f32,
+    pub corner_radius: Rounding,
     pub shadow: Shadow,
     pub fill: Color32,
     pub stroke: Stroke,
@@ -33,7 +33,7 @@ impl Frame {
     pub(crate) fn side_top_panel(style: &Style) -> Self {
         Self {
             margin: Vec2::new(8.0, 2.0),
-            corner_radius: 0.0,
+            corner_radius: Rounding::none(),
             fill: style.visuals.window_fill(),
             stroke: style.visuals.window_stroke(),
             ..Default::default()
@@ -43,7 +43,7 @@ impl Frame {
     pub(crate) fn central_panel(style: &Style) -> Self {
         Self {
             margin: Vec2::new(8.0, 8.0),
-            corner_radius: 0.0,
+            corner_radius: Rounding::none(),
             fill: style.visuals.window_fill(),
             stroke: Default::default(),
             ..Default::default()
@@ -103,8 +103,8 @@ impl Frame {
         self
     }
 
-    pub fn corner_radius(mut self, corner_radius: f32) -> Self {
-        self.corner_radius = corner_radius;
+    pub fn corner_radius(mut self, corner_radius: impl Into<Rounding>) -> Self {
+        self.corner_radius = corner_radius.into();
         self
     }
 

egui/src/containers/window.rs

@@ -705,36 +705,36 @@ fn paint_frame_interaction(
     let mut points = Vec::new();
 
     if interaction.right && !interaction.bottom && !interaction.top {
-        points.push(pos2(max.x, min.y + cr));
-        points.push(pos2(max.x, max.y - cr));
+        points.push(pos2(max.x, min.y + cr.ne));
+        points.push(pos2(max.x, max.y - cr.se));
     }
     if interaction.right && interaction.bottom {
-        points.push(pos2(max.x, min.y + cr));
-        points.push(pos2(max.x, max.y - cr));
-        add_circle_quadrant(&mut points, pos2(max.x - cr, max.y - cr), cr, 0.0);
+        points.push(pos2(max.x, min.y + cr.ne));
+        points.push(pos2(max.x, max.y - cr.se));
+        add_circle_quadrant(&mut points, pos2(max.x - cr.se, max.y - cr.se), cr.se, 0.0);
     }
     if interaction.bottom {
-        points.push(pos2(max.x - cr, max.y));
-        points.push(pos2(min.x + cr, max.y));
+        points.push(pos2(max.x - cr.se, max.y));
+        points.push(pos2(min.x + cr.sw, max.y));
     }
     if interaction.left && interaction.bottom {
-        add_circle_quadrant(&mut points, pos2(min.x + cr, max.y - cr), cr, 1.0);
+        add_circle_quadrant(&mut points, pos2(min.x + cr.sw, max.y - cr.sw), cr.sw, 1.0);
     }
     if interaction.left {
-        points.push(pos2(min.x, max.y - cr));
-        points.push(pos2(min.x, min.y + cr));
+        points.push(pos2(min.x, max.y - cr.sw));
+        points.push(pos2(min.x, min.y + cr.nw));
     }
     if interaction.left && interaction.top {
-        add_circle_quadrant(&mut points, pos2(min.x + cr, min.y + cr), cr, 2.0);
+        add_circle_quadrant(&mut points, pos2(min.x + cr.nw, min.y + cr.nw), cr.nw, 2.0);
     }
     if interaction.top {
-        points.push(pos2(min.x + cr, min.y));
-        points.push(pos2(max.x - cr, min.y));
+        points.push(pos2(min.x + cr.nw, min.y));
+        points.push(pos2(max.x - cr.ne, min.y));
     }
     if interaction.right && interaction.top {
-        add_circle_quadrant(&mut points, pos2(max.x - cr, min.y + cr), cr, 3.0);
-        points.push(pos2(max.x, min.y + cr));
-        points.push(pos2(max.x, max.y - cr));
+        add_circle_quadrant(&mut points, pos2(max.x - cr.ne, min.y + cr.ne), cr.ne, 3.0);
+        points.push(pos2(max.x, min.y + cr.ne));
+        points.push(pos2(max.x, max.y - cr.se));
     }
     ui.painter().add(Shape::line(points, visuals.bg_stroke));
 }

egui/src/lib.rs

@@ -387,8 +387,8 @@ pub use epaint::{
     color, mutex,
     text::{FontData, FontDefinitions, FontFamily, FontId},
     textures::TexturesDelta,
-    AlphaImage, ClippedMesh, Color32, ColorImage, ImageData, Rgba, Shape, Stroke, TextureHandle,
-    TextureId,
+    AlphaImage, ClippedMesh, Color32, ColorImage, ImageData, Rgba, Rounding, Shape, Stroke,
+    TextureHandle, TextureId,
 };
 
 pub mod text {

egui/src/painter.rs

@@ -6,7 +6,7 @@ use crate::{
 use epaint::{
     mutex::{Arc, RwLockReadGuard, RwLockWriteGuard},
     text::{Fonts, Galley},
-    CircleShape, RectShape, Shape, Stroke, TextShape,
+    CircleShape, RectShape, Rounding, Shape, Stroke, TextShape,
 };
 
 /// Helper to paint shapes and text to a specific region on a specific layer.
@@ -278,31 +278,41 @@ impl Painter {
     pub fn rect(
         &self,
         rect: Rect,
-        corner_radius: f32,
+        corner_radius: impl Into<Rounding>,
         fill_color: impl Into<Color32>,
         stroke: impl Into<Stroke>,
     ) {
         self.add(RectShape {
             rect,
-            corner_radius,
+            corner_radius: corner_radius.into(),
             fill: fill_color.into(),
             stroke: stroke.into(),
         });
     }
 
-    pub fn rect_filled(&self, rect: Rect, corner_radius: f32, fill_color: impl Into<Color32>) {
+    pub fn rect_filled(
+        &self,
+        rect: Rect,
+        corner_radius: impl Into<Rounding>,
+        fill_color: impl Into<Color32>,
+    ) {
         self.add(RectShape {
             rect,
-            corner_radius,
+            corner_radius: corner_radius.into(),
             fill: fill_color.into(),
             stroke: Default::default(),
         });
     }
 
-    pub fn rect_stroke(&self, rect: Rect, corner_radius: f32, stroke: impl Into<Stroke>) {
+    pub fn rect_stroke(
+        &self,
+        rect: Rect,
+        corner_radius: impl Into<Rounding>,
+        stroke: impl Into<Stroke>,
+    ) {
         self.add(RectShape {
             rect,
-            corner_radius,
+            corner_radius: corner_radius.into(),
             fill: Default::default(),
             stroke: stroke.into(),
         });

egui/src/style.rs

@@ -3,7 +3,7 @@
 #![allow(clippy::if_same_then_else)]
 
 use crate::{color::*, emath::*, FontFamily, FontId, Response, RichText, WidgetText};
-use epaint::{mutex::Arc, Shadow, Stroke};
+use epaint::{mutex::Arc, Rounding, Shadow, Stroke};
 use std::collections::BTreeMap;
 
 // ----------------------------------------------------------------------------
@@ -344,7 +344,7 @@ pub struct Visuals {
     /// Background color behind code-styled monospaced labels.
     pub code_bg_color: Color32,
 
-    pub window_corner_radius: f32,
+    pub window_corner_radius: Rounding,
     pub window_shadow: Shadow,
 
     pub popup_shadow: Shadow,
@@ -453,7 +453,7 @@ pub struct WidgetVisuals {
     pub bg_stroke: Stroke,
 
     /// Button frames etc.
-    pub corner_radius: f32,
+    pub corner_radius: Rounding,
 
     /// Stroke and text color of the interactive part of a component (button text, slider grab, check-mark, …).
     pub fg_stroke: Stroke,
@@ -566,7 +566,7 @@ impl Visuals {
             faint_bg_color: Color32::from_gray(24),
             extreme_bg_color: Color32::from_gray(10),
             code_bg_color: Color32::from_gray(64),
-            window_corner_radius: 6.0,
+            window_corner_radius: Rounding::same(6.0),
             window_shadow: Shadow::big_dark(),
             popup_shadow: Shadow::small_dark(),
             resize_corner_size: 12.0,
@@ -629,35 +629,35 @@ impl Widgets {
                 bg_fill: Color32::from_gray(27), // window background
                 bg_stroke: Stroke::new(1.0, Color32::from_gray(60)), // separators, indentation lines, windows outlines
                 fg_stroke: Stroke::new(1.0, Color32::from_gray(140)), // normal text color
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 expansion: 0.0,
             },
             inactive: WidgetVisuals {
                 bg_fill: Color32::from_gray(60), // button background
                 bg_stroke: Default::default(),
                 fg_stroke: Stroke::new(1.0, Color32::from_gray(180)), // button text
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 expansion: 0.0,
             },
             hovered: WidgetVisuals {
                 bg_fill: Color32::from_gray(70),
                 bg_stroke: Stroke::new(1.0, Color32::from_gray(150)), // e.g. hover over window edge or button
                 fg_stroke: Stroke::new(1.5, Color32::from_gray(240)),
-                corner_radius: 3.0,
+                corner_radius: Rounding::same(3.0),
                 expansion: 1.0,
             },
             active: WidgetVisuals {
                 bg_fill: Color32::from_gray(55),
                 bg_stroke: Stroke::new(1.0, Color32::WHITE),
                 fg_stroke: Stroke::new(2.0, Color32::WHITE),
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 expansion: 1.0,
             },
             open: WidgetVisuals {
                 bg_fill: Color32::from_gray(27),
                 bg_stroke: Stroke::new(1.0, Color32::from_gray(60)),
                 fg_stroke: Stroke::new(1.0, Color32::from_gray(210)),
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 expansion: 0.0,
             },
         }
@@ -669,35 +669,35 @@ impl Widgets {
                 bg_fill: Color32::from_gray(235), // window background
                 bg_stroke: Stroke::new(1.0, Color32::from_gray(190)), // separators, indentation lines, windows outlines
                 fg_stroke: Stroke::new(1.0, Color32::from_gray(100)), // normal text color
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 expansion: 0.0,
             },
             inactive: WidgetVisuals {
                 bg_fill: Color32::from_gray(215), // button background
                 bg_stroke: Default::default(),
                 fg_stroke: Stroke::new(1.0, Color32::from_gray(80)), // button text
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 expansion: 0.0,
             },
             hovered: WidgetVisuals {
                 bg_fill: Color32::from_gray(210),
                 bg_stroke: Stroke::new(1.0, Color32::from_gray(105)), // e.g. hover over window edge or button
                 fg_stroke: Stroke::new(1.5, Color32::BLACK),
-                corner_radius: 3.0,
+                corner_radius: Rounding::same(3.0),
                 expansion: 1.0,
             },
             active: WidgetVisuals {
                 bg_fill: Color32::from_gray(165),
                 bg_stroke: Stroke::new(1.0, Color32::BLACK),
                 fg_stroke: Stroke::new(2.0, Color32::BLACK),
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 expansion: 1.0,
             },
             open: WidgetVisuals {
                 bg_fill: Color32::from_gray(220),
                 bg_stroke: Stroke::new(1.0, Color32::from_gray(160)),
                 fg_stroke: Stroke::new(1.0, Color32::BLACK),
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 expansion: 0.0,
             },
         }
@@ -949,7 +949,12 @@ impl WidgetVisuals {
         } = self;
         ui_color(ui, bg_fill, "bg_fill");
         stroke_ui(ui, bg_stroke, "bg_stroke");
-        ui.add(Slider::new(corner_radius, 0.0..=10.0).text("corner_radius"));
+
+        ui.add(Slider::new(&mut corner_radius.nw, 0.0..=10.0).text("corner_radius_nw"));
+        ui.add(Slider::new(&mut corner_radius.ne, 0.0..=10.0).text("corner_radius_ne"));
+        ui.add(Slider::new(&mut corner_radius.sw, 0.0..=10.0).text("corner_radius_sw"));
+        ui.add(Slider::new(&mut corner_radius.se, 0.0..=10.0).text("corner_radius_se"));
+
         stroke_ui(ui, fg_stroke, "fg_stroke (text)");
         ui.add(Slider::new(expansion, -5.0..=5.0).text("expansion"))
             .on_hover_text("make shapes this much larger");
@@ -1024,7 +1029,13 @@ impl Visuals {
             // Common shortcuts
             ui_color(ui, &mut widgets.noninteractive.bg_fill, "Fill");
             stroke_ui(ui, &mut widgets.noninteractive.bg_stroke, "Outline");
-            ui.add(Slider::new(window_corner_radius, 0.0..=20.0).text("Rounding"));
+
+            ui.label("Rounding");
+            ui.add(Slider::new(&mut window_corner_radius.nw, 0.0..=20.0).text("Top Left"));
+            ui.add(Slider::new(&mut window_corner_radius.ne, 0.0..=20.0).text("Top Right"));
+            ui.add(Slider::new(&mut window_corner_radius.sw, 0.0..=20.0).text("Bottom Left"));
+            ui.add(Slider::new(&mut window_corner_radius.se, 0.0..=20.0).text("Bottom Right"));
+
             shadow_ui(ui, window_shadow, "Shadow");
             shadow_ui(ui, popup_shadow, "Shadow (small menus and popups)");
         });

egui/src/widgets/button.rs

@@ -457,7 +457,12 @@ impl Widget for ImageButton {
         if ui.is_rect_visible(rect) {
             let (expansion, corner_radius, fill, stroke) = if selected {
                 let selection = ui.visuals().selection;
-                (-padding, 0.0, selection.bg_fill, selection.stroke)
+                (
+                    -padding,
+                    Rounding::none(),
+                    selection.bg_fill,
+                    selection.stroke,
+                )
             } else if frame {
                 let visuals = ui.style().interact(&response);
                 let expansion = if response.hovered {

egui/src/widgets/color_picker.rs

@@ -61,7 +61,7 @@ fn show_hsva(ui: &mut Ui, color: Hsva, desired_size: Vec2) -> Response {
         } else {
             ui.painter().add(RectShape {
                 rect,
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 fill: color.into(),
                 stroke: Stroke::new(3.0, color.to_opaque()),
             });
@@ -90,7 +90,13 @@ fn color_button(ui: &mut Ui, color: Color32, open: bool) -> Response {
         ui.painter().rect_filled(left_half, 0.0, color);
         ui.painter().rect_filled(right_half, 0.0, color.to_opaque());
 
-        let corner_radius = visuals.corner_radius.at_most(2.0);
+        let corner_radius = Rounding {
+            nw: visuals.corner_radius.nw.at_most(2.0),
+            ne: visuals.corner_radius.ne.at_most(2.0),
+            sw: visuals.corner_radius.sw.at_most(2.0),
+            se: visuals.corner_radius.se.at_most(2.0),
+        };
+
         ui.painter()
             .rect_stroke(rect, corner_radius, (2.0, visuals.bg_fill)); // fill is intentional, because default style has no border
     }

egui/src/widgets/plot/items/bar.rs

@@ -1,5 +1,5 @@
 use crate::emath::NumExt;
-use crate::epaint::{Color32, RectShape, Shape, Stroke};
+use crate::epaint::{Color32, RectShape, Rounding, Shape, Stroke};
 
 use super::{add_rulers_and_text, highlighted_color, Orientation, PlotConfig, RectElement};
 use crate::plot::{BarChart, ScreenTransform, Value};
@@ -129,7 +129,7 @@ impl Bar {
         let rect = transform.rect_from_values(&self.bounds_min(), &self.bounds_max());
         let rect = Shape::Rect(RectShape {
             rect,
-            corner_radius: 0.0,
+            corner_radius: Rounding::none(),
             fill,
             stroke,
         });

egui/src/widgets/plot/items/box_elem.rs

@@ -1,5 +1,5 @@
 use crate::emath::NumExt;
-use crate::epaint::{Color32, RectShape, Shape, Stroke};
+use crate::epaint::{Color32, RectShape, Rounding, Shape, Stroke};
 
 use super::{add_rulers_and_text, highlighted_color, Orientation, PlotConfig, RectElement};
 use crate::plot::{BoxPlot, ScreenTransform, Value};
@@ -152,7 +152,7 @@ impl BoxElem {
         );
         let rect = Shape::Rect(RectShape {
             rect,
-            corner_radius: 0.0,
+            corner_radius: Rounding::none(),
             fill,
             stroke,
         });

egui/src/widgets/plot/mod.rs

@@ -479,7 +479,7 @@ impl Plot {
         if show_background {
             ui.painter().sub_region(rect).add(epaint::RectShape {
                 rect,
-                corner_radius: 2.0,
+                corner_radius: Rounding::same(2.0),
                 fill: ui.visuals().extreme_bg_color,
                 stroke: ui.visuals().widgets.noninteractive.bg_stroke,
             });

epaint/src/lib.rs

@@ -110,7 +110,7 @@ pub use {
     image::{AlphaImage, ColorImage, ImageData, ImageDelta},
     mesh::{Mesh, Mesh16, Vertex},
     shadow::Shadow,
-    shape::{CircleShape, PathShape, RectShape, Shape, TextShape},
+    shape::{CircleShape, PathShape, RectShape, Rounding, Shape, TextShape},
     stats::PaintStats,
     stroke::Stroke,
     tessellator::{tessellate_shapes, TessellationOptions, Tessellator},