test: Add demo

Author: bircni

demo/src/plot_demo.rs

@@ -24,6 +24,7 @@ enum Panel {
     Interaction,
     CustomAxes,
     LinkedAxes,
+    Heatmap,
 }
 
 impl Default for Panel {
@@ -44,6 +45,7 @@ pub struct PlotDemo {
     interaction_demo: InteractionDemo,
     custom_axes_demo: CustomAxesDemo,
     linked_axes_demo: LinkedAxesDemo,
+    heatmap_demo: HeatmapDemo,
     open_panel: Panel,
 }
 
@@ -124,6 +126,7 @@ impl PlotDemo {
             ui.selectable_value(&mut self.open_panel, Panel::Interaction, "Interaction");
             ui.selectable_value(&mut self.open_panel, Panel::CustomAxes, "Custom Axes");
             ui.selectable_value(&mut self.open_panel, Panel::LinkedAxes, "Linked Axes");
+            ui.selectable_value(&mut self.open_panel, Panel::Heatmap, "Heatmap");
         });
         ui.separator();
 
@@ -152,6 +155,9 @@ impl PlotDemo {
             Panel::LinkedAxes => {
                 self.linked_axes_demo.ui(ui);
             }
+            Panel::Heatmap => {
+                self.heatmap_demo.ui(ui);
+            }
         }
     }
 }
@@ -1204,3 +1210,92 @@ fn is_approx_zero(val: f64) -> bool {
 fn is_approx_integer(val: f64) -> bool {
     val.fract().abs() < 1e-6
 }
+
+#[derive(PartialEq, serde::Serialize, serde::Deserialize)]
+struct HeatmapDemo {
+    tick: f64,
+    animate: bool,
+    show_labels: bool,
+    palette: Vec<Color32>,
+    rows: usize,
+    cols: usize,
+}
+
+pub const TURBO_COLORMAP: [Color32; 10] = [
+    Color32::from_rgb(48, 18, 59),
+    Color32::from_rgb(35, 106, 141),
+    Color32::from_rgb(30, 160, 140),
+    Color32::from_rgb(88, 200, 98),
+    Color32::from_rgb(164, 223, 39),
+    Color32::from_rgb(228, 223, 14),
+    Color32::from_rgb(250, 187, 13),
+    Color32::from_rgb(246, 135, 8),
+    Color32::from_rgb(213, 68, 2),
+    Color32::from_rgb(122, 4, 2),
+];
+
+impl Default for HeatmapDemo {
+    fn default() -> Self {
+        Self {
+            tick: 0.0,
+            animate: false,
+            show_labels: true,
+            palette: TURBO_COLORMAP.to_vec(),
+            rows: 10,
+            cols: 15,
+        }
+    }
+}
+
+impl HeatmapDemo {
+    fn ui(&mut self, ui: &mut egui::Ui) -> Response {
+        ui.checkbox(&mut self.animate, "Animate");
+        if self.animate {
+            ui.ctx().request_repaint();
+            self.tick += 1.0;
+        }
+        ui.checkbox(&mut self.show_labels, "Show labels");
+        ui.add(egui::Slider::new(&mut self.rows, 1..=100).text("Rows"));
+        ui.add(egui::Slider::new(&mut self.cols, 1..=100).text("Columns"));
+        let mut values = Vec::new();
+        for y in 0..self.rows {
+            for x in 0..self.cols {
+                let y = y as f64;
+                let x = x as f64;
+                let cols = self.cols as f64;
+                let rows = self.rows as f64;
+                values.push(((x + self.tick) / rows).sin() + ((y + self.tick) / cols).cos());
+            }
+        }
+        ui.add_enabled_ui(self.palette.len() > 1, |ui| {
+            if ui.button("Pop color").clicked() {
+                self.palette.pop();
+            }
+        });
+        if ui.button("Push color").clicked() {
+            self.palette
+                .push(*self.palette.last().expect("Palette is empty"));
+        }
+        ui.horizontal(|ui| {
+            for color in &mut self.palette {
+                ui.color_edit_button_srgba(color);
+            }
+        });
+
+        let heatmap = egui_plot::Heatmap::<128>::new(values, self.cols)
+            .expect("Failed to create heatmap")
+            .palette(&self.palette)
+            .show_labels(self.show_labels);
+        Plot::new("Heatmap Demo")
+            .legend(Legend::default())
+            .allow_zoom(false)
+            .allow_scroll(false)
+            .allow_drag(false)
+            .allow_boxed_zoom(false)
+            .set_margin_fraction(vec2(0.0, 0.0))
+            .show(ui, |plot_ui| {
+                plot_ui.heatmap(heatmap);
+            })
+            .response
+    }
+}