[refactor] Add helpful constructors to PaintCmd

egui/src/containers/collapsing_header.rs

@@ -122,12 +122,7 @@ pub fn paint_icon(ui: &mut Ui, openness: f32, response: &Response) {
         *p = rect.center() + v;
     }
 
-    ui.painter().add(PaintCmd::Path {
-        points,
-        closed: true,
-        fill: Default::default(),
-        stroke,
-    });
+    ui.painter().add(PaintCmd::closed_line(points, stroke));
 }
 
 /// A header which can be collapsed/expanded, revealing a contained `Ui` region.

egui/src/containers/combo_box.rs

@@ -116,10 +116,8 @@ fn paint_icon(painter: &Painter, rect: Rect, visuals: &WidgetVisuals) {
         rect.center(),
         vec2(rect.width() * 0.7, rect.height() * 0.45),
     );
-    painter.add(PaintCmd::Path {
-        points: vec![rect.left_top(), rect.right_top(), rect.center_bottom()],
-        closed: true,
-        fill: Default::default(),
-        stroke: visuals.fg_stroke,
-    });
+    painter.add(PaintCmd::closed_line(
+        vec![rect.left_top(), rect.right_top(), rect.center_bottom()],
+        visuals.fg_stroke,
+    ));
 }

egui/src/containers/window.rs

@@ -583,12 +583,7 @@ fn paint_frame_interaction(
         points.push(pos2(max.x, min.y + cr));
         points.push(pos2(max.x, max.y - cr));
     }
-    ui.painter().add(PaintCmd::Path {
-        points,
-        closed: false,
-        fill: Default::default(),
-        stroke: visuals.bg_stroke,
-    });
+    ui.painter().add(PaintCmd::line(points, visuals.bg_stroke));
 }
 
 // ----------------------------------------------------------------------------

egui/src/demos/demo_window.rs

@@ -318,12 +318,7 @@ impl Painting {
         for line in &self.lines {
             if line.len() >= 2 {
                 let points: Vec<Pos2> = line.iter().map(|p| rect.min + *p).collect();
-                painter.add(paint::PaintCmd::Path {
-                    points,
-                    closed: false,
-                    stroke: self.stroke,
-                    fill: Default::default(),
-                });
+                painter.add(paint::PaintCmd::line(points, self.stroke));
             }
         }
     }

egui/src/paint/command.rs

@@ -46,6 +46,7 @@ pub enum PaintCmd {
     Triangles(Triangles),
 }
 
+/// ## Constructors
 impl PaintCmd {
     pub fn line_segment(points: [Pos2; 2], stroke: impl Into<Stroke>) -> Self {
         Self::LineSegment {
@@ -54,6 +55,33 @@ impl PaintCmd {
         }
     }
 
+    pub fn line(points: Vec<Pos2>, stroke: impl Into<Stroke>) -> Self {
+        Self::Path {
+            points,
+            closed: false,
+            fill: Default::default(),
+            stroke: stroke.into(),
+        }
+    }
+
+    pub fn closed_line(points: Vec<Pos2>, stroke: impl Into<Stroke>) -> Self {
+        Self::Path {
+            points,
+            closed: true,
+            fill: Default::default(),
+            stroke: stroke.into(),
+        }
+    }
+
+    pub fn polygon(points: Vec<Pos2>, fill: impl Into<Srgba>, stroke: impl Into<Stroke>) -> Self {
+        Self::Path {
+            points,
+            closed: true,
+            fill: fill.into(),
+            stroke: stroke.into(),
+        }
+    }
+
     pub fn circle_filled(center: Pos2, radius: f32, fill_color: impl Into<Srgba>) -> Self {
         Self::Circle {
             center,
@@ -108,7 +136,10 @@ impl PaintCmd {
             color,
         }
     }
+}
 
+/// ## Operations
+impl PaintCmd {
     pub fn triangles(triangles: Triangles) -> Self {
         debug_assert!(triangles.is_valid());
         Self::Triangles(triangles)

egui/src/widgets/color_picker.rs

@@ -115,16 +115,15 @@ fn color_slider_1d(ui: &mut Ui, value: &mut f32, color_at: impl Fn(f32) -> Srgba
         let x = lerp(rect.left()..=rect.right(), *value);
         let r = rect.height() / 4.0;
         let picked_color = color_at(*value);
-        ui.painter().add(PaintCmd::Path {
-            points: vec![
+        ui.painter().add(PaintCmd::polygon(
+            vec![
                 pos2(x - r, rect.bottom()),
                 pos2(x + r, rect.bottom()),
                 pos2(x, rect.center().y),
             ],
-            closed: true,
-            fill: picked_color,
-            stroke: Stroke::new(visuals.fg_stroke.width, contrast_color(picked_color)),
-        });
+            picked_color,
+            Stroke::new(visuals.fg_stroke.width, contrast_color(picked_color)),
+        ));
     }
 
     response

egui/src/widgets/mod.rs

@@ -411,16 +411,15 @@ impl<'a> Widget for Checkbox<'a> {
         });
 
         if *checked {
-            ui.painter().add(PaintCmd::Path {
-                points: vec![
+            // Check mark:
+            ui.painter().add(PaintCmd::line(
+                vec![
                     pos2(small_icon_rect.left(), small_icon_rect.center().y),
                     pos2(small_icon_rect.center().x, small_icon_rect.bottom()),
                     pos2(small_icon_rect.right(), small_icon_rect.top()),
                 ],
-                closed: false,
-                fill: Default::default(),
-                stroke: visuals.fg_stroke,
-            });
+                visuals.fg_stroke,
+            ));
         }
 
         let text_color = text_color