heatmap: Add example to plot demo

crates/egui/src/widgets/plot/items/mod.rs

@@ -1626,6 +1626,25 @@ pub struct Heatmap<const RESOLUTION: usize> {
     tile_size: Vec2,
 }
 
+impl<const RESOLUTION: usize> PartialEq for Heatmap<RESOLUTION> {
+    /// manual implementation of PartialEq because formatter and color mapping do not impl PartialEq.
+    ///
+    /// > NOTE: custom_mapping and formatter are ignored
+    fn eq(&self, other: &Self) -> bool {
+        self.pos == other.pos
+            && self.values == other.values
+            && self.cols == other.cols
+            && self.rows == other.rows
+            && self.min == other.min
+            && self.max == other.max
+            && self.show_labels == other.show_labels
+            && self.palette == other.palette
+            && self.highlight == other.highlight
+            && self.name == other.name
+            && self.tile_size == other.tile_size
+    }
+}
+
 impl<const RESOLUTION: usize> Heatmap<RESOLUTION> {
     /// Create a 2D heatmap. Will automatically infer number of rows.
     ///
@@ -1802,7 +1821,7 @@ impl<const RESOLUTION: usize> Heatmap<RESOLUTION> {
         self
     }
 
-    fn push_shapes(&self, ui: &Ui, transform: &ScreenTransform, shapes: &mut Vec<Shape>) {
+    fn push_shapes(&self, ui: &Ui, transform: &PlotTransform, shapes: &mut Vec<Shape>) {
         let mut mesh = Mesh::default();
         let mut labels: Vec<Shape> = Vec::new();
         for i in 0..self.values.len() {
@@ -1820,7 +1839,7 @@ impl<const RESOLUTION: usize> Heatmap<RESOLUTION> {
     fn tile_view_info(
         &self,
         ui: &Ui,
-        transform: &ScreenTransform,
+        transform: &PlotTransform,
         index: usize,
     ) -> (Rect, Color32, Shape) {
         let v = self.values[index];
@@ -1883,7 +1902,7 @@ impl<const RESOLUTION: usize> Heatmap<RESOLUTION> {
 }
 
 impl<const RESOLUTION: usize> PlotItem for Heatmap<RESOLUTION> {
-    fn shapes(&self, ui: &mut Ui, transform: &ScreenTransform, shapes: &mut Vec<Shape>) {
+    fn shapes(&self, ui: &mut Ui, transform: &PlotTransform, shapes: &mut Vec<Shape>) {
         self.push_shapes(ui, transform, shapes);
     }
 
@@ -1922,7 +1941,7 @@ impl<const RESOLUTION: usize> PlotItem for Heatmap<RESOLUTION> {
         }
     }
 
-    fn find_closest(&self, point: Pos2, transform: &ScreenTransform) -> Option<ClosestElem> {
+    fn find_closest(&self, point: Pos2, transform: &PlotTransform) -> Option<ClosestElem> {
         self.values
             .clone() // FIXME: is there a better solution that cloning?
             .into_iter()

crates/egui_demo_lib/src/demo/plot_demo.rs

@@ -1,7 +1,7 @@
 use std::f64::consts::TAU;
 use std::ops::RangeInclusive;
 
-use egui::plot::{AxisBools, GridInput, GridMark, PlotResponse};
+use egui::plot::{AxisBools, GridInput, GridMark, Heatmap, PlotResponse};
 use egui::*;
 use plot::{
     Arrows, Bar, BarChart, BoxElem, BoxPlot, BoxSpread, CoordinatesFormatter, Corner, HLine,
@@ -21,6 +21,7 @@ enum Panel {
     Interaction,
     CustomAxes,
     LinkedAxes,
+    Heatmap,
 }
 
 impl Default for Panel {
@@ -41,6 +42,7 @@ pub struct PlotDemo {
     interaction_demo: InteractionDemo,
     custom_axes_demo: CustomAxisDemo,
     linked_axes_demo: LinkedAxisDemo,
+    heatmap_demo: HeatmapDemo,
     open_panel: Panel,
 }
 
@@ -87,6 +89,7 @@ impl super::View for 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();
 
@@ -115,6 +118,9 @@ impl super::View for PlotDemo {
             Panel::LinkedAxes => {
                 self.linked_axes_demo.ui(ui);
             }
+            Panel::Heatmap => {
+                self.heatmap_demo.ui(ui);
+            }
         }
     }
 }
@@ -1006,3 +1012,78 @@ impl ChartsDemo {
             .response
     }
 }
+#[derive(PartialEq)]
+struct HeatmapDemo {
+    tick: f64,
+    animate: bool,
+    show_labels: bool,
+    palette: Vec<Color32>,
+    rows: usize,
+    cols: usize,
+}
+
+impl Default for HeatmapDemo {
+    fn default() -> Self {
+        Self {
+            tick: 0.0,
+            animate: true,
+            show_labels: false,
+            palette: vec![Color32::WHITE, Color32::RED, Color32::BLACK],
+            rows: 10,
+            cols: 15,
+        }
+    }
+}
+
+impl HeatmapDemo {
+    fn ui(&mut self, ui: &mut 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(Slider::new(&mut self.rows, 1..=100).text("Rows"));
+        ui.add(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())
+            }
+        }
+        if self.palette.len() > 1 {}
+        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().unwrap());
+        }
+        ui.horizontal(|ui| {
+            for color in &mut self.palette {
+                ui.color_edit_button_srgba(color);
+            }
+        });
+
+        let heatmap = Heatmap::<128>::new(values, self.cols)
+            .unwrap()
+            .palette(self.palette.clone())
+            .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
+    }
+}