Basic triangle mosaic.

src/component/triangle.rs

@@ -22,11 +22,17 @@ impl Default for Triangle {
 }
 
 impl Triangle {
+    /// Draws the triangle to the ui.
     pub fn show(&self, ui: &mut Ui) {
-        ui.painter().add(Shape::convex_polygon(
+        ui.painter().add(self.shape());
+    }
+
+    /// Gets the raw shape.
+    pub fn shape(&self) -> Shape {
+        Shape::convex_polygon(
             self.points.into(),
             self.fill,
             Stroke::new(self.stroke_width, self.stroke),
-        ));
+        )
     }
 }

src/slide/s8_mosaic.rs

+use crate::color::set_alpha;
 use crate::component::grid::Grid;
 use crate::component::image::{Image, ImagePosition};
 use crate::component::triangle::Triangle;
-use crate::ctx_img;
-use crate::egui::{Color32, TextureHandle, Ui, Vec2};
+use crate::egui::{TextureHandle, Ui, Vec2};
+use crate::img;
 use crate::slide::Slide;
 use eframe::egui::style::Margin;
-use eframe::egui::{Frame, Pos2};
+use eframe::egui::{ColorImage, Frame, Pos2, Shape};
+use eframe::emath::Rot2;
+use rand::{thread_rng, Rng};
 
-#[derive(Default)]
 pub struct Mosaic {
-    squirrel: Option<TextureHandle>,
+    image: ColorImage,
+    texture: Option<TextureHandle>,
+    shapes: Vec<Shape>,
+}
+
+impl Default for Mosaic {
+    fn default() -> Self {
+        Self {
+            image: img!("squirrel0.png"),
+            texture: None,
+            shapes: Vec::new(),
+        }
+    }
 }
 
 impl Slide for Mosaic {
@@ -17,18 +31,6 @@ impl Slide for Mosaic {
         // TODO: Finish this slide.
         Frame::none().margin(Margin::same(20.0)).show(ui, |ui| {
             ui.heading("Generative Image Processing");
-
-            Triangle {
-                points: [
-                    Pos2::new(200.0, 150.0),
-                    Pos2::new(500.0, 220.0),
-                    Pos2::new(300.0, 400.0),
-                ],
-                stroke_width: 0.0,
-                fill: Color32::RED,
-                ..Triangle::default()
-            }
-            .show(ui)
         });
 
         Image::default()
@@ -37,8 +39,9 @@ impl Slide for Mosaic {
             .margin(16.0)
             .show(
                 ui,
-                self.squirrel
-                    .get_or_insert_with(|| ctx_img!(ui.ctx(), "squirrel0.png")),
+                self.texture.get_or_insert_with(|| {
+                    ui.ctx().load_texture("squirrel0.png", self.image.clone())
+                }),
             );
 
         Grid {
@@ -47,6 +50,38 @@ impl Slide for Mosaic {
             offset_x: 300.0,
             ..Grid::default()
         }
-        .show(ui.ctx());
+        .show_with_overlays(ui.ctx(), |ui, to_screen| {
+            ui.ctx().request_repaint();
+
+            let mut rng = thread_rng();
+
+            for _ in 0..50 {
+                let x: f32 = rng.gen();
+                let y: f32 = rng.gen();
+                let size: f32 = rng.gen::<f32>() * 0.025;
+                let rot = Rot2::from_angle(rng.gen::<f32>() * std::f32::consts::TAU);
+                let center = Pos2::new(x, y);
+                let image_x =
+                    ((x * self.image.width() as f32) as usize).min(self.image.width() - 1);
+                let image_y =
+                    ((y * self.image.height() as f32) as usize).min(self.image.height() - 1);
+
+                self.shapes.push(
+                    Triangle {
+                        points: [
+                            to_screen * (center + rot * Vec2::new(-1.0, -1.0) * size),
+                            to_screen * (center + rot * Vec2::new(1.0, -1.0) * size),
+                            to_screen * (center + rot * Vec2::new(-1.0, 1.0) * size),
+                        ],
+                        stroke_width: 0.0,
+                        fill: set_alpha(self.image[(image_x, image_y)], 0.2),
+                        ..Triangle::default()
+                    }
+                    .shape(),
+                );
+            }
+
+            ui.painter().extend(self.shapes.clone());
+        });
     }
 }