egui: implement painting of shapes

src/bin/topola-egui/app.rs

@@ -1,3 +1,10 @@
+use topola::{
+    layout::geometry::shape::{BendShape, DotShape, SegShape, Shape},
+    math::Circle,
+};
+
+use crate::painter::Painter;
+
 /// Deserialize/Serialize is needed to persist app state between restarts.
 #[derive(serde::Deserialize, serde::Serialize)]
 #[serde(default)]
@@ -57,11 +64,43 @@ impl eframe::App for App {
 
         egui::CentralPanel::default().show(ctx, |ui| {
             egui::Frame::canvas(ui.style()).show(ui, |ui| {
-                let (rect, response) =
-                    ui.allocate_exact_size(egui::Vec2::splat(300.0), egui::Sense::drag());
-                let stroke = egui::Stroke::new(10.0, egui::Color32::from_white_alpha(255));
-                ui.painter()
-                    .line_segment([[10.0, 10.0].into(), [30.0, 30.0].into()], stroke);
+                ui.ctx().request_repaint();
+
+                let desired_size = ui.available_width() * egui::vec2(1.0, 0.5);
+                let (_id, viewport_rect) = ui.allocate_space(desired_size);
+
+                let transform = egui::emath::RectTransform::from_to(
+                    egui::Rect::from_x_y_ranges(0.0..=1000.0, 0.0..=500.0),
+                    viewport_rect,
+                );
+                let mut painter = Painter::new(ui, transform);
+
+                let dot_shape = Shape::Dot(DotShape {
+                    c: Circle {
+                        pos: [50.0, 100.0].into(),
+                        r: 10.0,
+                    },
+                });
+
+                let seg_shape = Shape::Seg(SegShape {
+                    from: [200.0, 25.0].into(),
+                    to: [300.0, 300.0].into(),
+                    width: 5.0,
+                });
+
+                let bend_shape = Shape::Bend(BendShape {
+                    from: [100.0, 100.0].into(),
+                    to: [160.0, 160.0].into(),
+                    c: Circle {
+                        pos: [130.0, 130.0].into(),
+                        r: 30.0,
+                    },
+                    width: 12.0,
+                });
+
+                painter.paint_shape(&dot_shape, egui::Color32::from_rgb(255, 0, 0));
+                painter.paint_shape(&seg_shape, egui::Color32::from_rgb(128, 128, 128));
+                painter.paint_shape(&bend_shape, egui::Color32::from_rgb(255, 255, 0));
             })
         });
     }

src/bin/topola-egui/painter.rs

@@ -1 +1,58 @@
+use egui::{emath::RectTransform, epaint, Color32, Pos2, Ui};
+use geo::Point;
+use topola::layout::geometry::shape::Shape;
 
+pub struct Painter<'a> {
+    ui: &'a mut egui::Ui,
+    transform: RectTransform,
+}
+
+impl<'a> Painter<'a> {
+    pub fn new(ui: &'a mut Ui, transform: RectTransform) -> Self {
+        Self { ui, transform }
+    }
+
+    pub fn paint_shape(&mut self, shape: &Shape, color: Color32) {
+        let epaint_shape = match shape {
+            Shape::Dot(dot) => epaint::Shape::circle_filled(
+                self.transform
+                    .transform_pos([dot.c.pos.x() as f32, dot.c.pos.y() as f32].into()),
+                dot.c.r as f32,
+                color,
+            ),
+            Shape::Seg(seg) => epaint::Shape::line_segment(
+                [
+                    self.transform
+                        .transform_pos([seg.from.x() as f32, seg.from.y() as f32].into()),
+                    self.transform
+                        .transform_pos([seg.to.x() as f32, seg.to.y() as f32].into()),
+                ],
+                egui::Stroke::new(seg.width as f32, color),
+            ),
+            Shape::Bend(bend) => {
+                let delta_from = bend.from - bend.c.pos;
+                let delta_to = bend.to - bend.c.pos;
+
+                let angle_from = delta_from.y().atan2(delta_from.x());
+                let angle_to = delta_to.y().atan2(delta_to.x());
+                let mut points: Vec<Pos2> = vec![];
+
+                let angle_step = (angle_to - angle_from) / 100.0;
+
+                for i in 0..100 {
+                    let x = bend.c.pos.x() + bend.c.r * (angle_from + i as f64 * angle_step).cos();
+                    let y = bend.c.pos.y() + bend.c.r * (angle_from + i as f64 * angle_step).sin();
+                    points.push(self.transform.transform_pos([x as f32, y as f32].into()));
+                }
+
+                epaint::Shape::line(points, egui::Stroke::new(bend.width as f32, color))
+            }
+        };
+
+        self.ui.painter().add(epaint_shape);
+    }
+
+    pub fn paint_edge(&mut self, from: Point, to: Point, color: Color32) {
+        //
+    }
+}