From 1e773605f6f197e85aff1feef9cd9d7862ca25f7 Mon Sep 17 00:00:00 2001
From: Simon Gardling <titaniumtown@gmail.com>
Date: Wed, 23 Feb 2022 19:43:19 -0500
Subject: [PATCH] progress

---
 Cargo.toml           |  2 ++
 TODO.md              |  1 +
 src/chart_manager.rs | 13 ++++++++++
 src/egui_app.rs      | 60 +++++++++++++++++++++++++++++++++-----------
 4 files changed, 61 insertions(+), 15 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 5ef0a66..47da783 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,6 +18,8 @@ egui = "0.17.0"
 eframe = "0.17.0"
 emath = "0.17.0"
 epaint = "0.17.0"
+instant = { version = "0.1.12", features = ["wasm-bindgen"] }
+
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 console_error_panic_hook = "0.1.7"
 tracing-wasm = "0.2.1"
diff --git a/TODO.md b/TODO.md
index cfabc77..2ed2a34 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,5 +1,6 @@
 ## TODO:
 1. Port to [egui](https://github.com/emilk/egui)
     - Proper support for dynamic chart display size.
+    - Don't re-render plot on mouse movement
 2. Multiple functions in one graph.
 3. Non `y=` functions.
\ No newline at end of file
diff --git a/src/chart_manager.rs b/src/chart_manager.rs
index 320e09e..3bb5fad 100644
--- a/src/chart_manager.rs
+++ b/src/chart_manager.rs
@@ -56,6 +56,19 @@ impl ChartManager {
         (filtered_data, rect_data, area)
     }
 
+    pub fn do_update_front(&self, resolution: usize, num_interval: usize) -> bool {
+        (self.resolution != resolution) | (num_interval != self.num_interval)
+    }
+
+    pub fn do_update_back(&self, func_str_new: String, min_x: f64, max_x: f64) -> bool {
+        let func_str: String = add_asterisks(func_str_new);
+        let update_func: bool = !self.function.str_compare(func_str.clone());
+
+        let underlying_update = update_func | (min_x != self.min_x) | (max_x != self.max_x);
+
+        underlying_update
+    }
+
     #[allow(clippy::too_many_arguments)]
     pub fn update(
         &mut self, func_str_new: String, min_x: f64, max_x: f64, num_interval: usize,
diff --git a/src/egui_app.rs b/src/egui_app.rs
index 30e2616..e74735b 100644
--- a/src/egui_app.rs
+++ b/src/egui_app.rs
@@ -1,12 +1,11 @@
 use crate::chart_manager::ChartManager;
-use crate::misc::{digits_precision, test_func};
+use crate::misc::{digits_precision, test_func, Cache};
 use eframe::{egui, epi};
 use egui::widgets::plot::{Bar, BarChart};
 use egui::{
     plot::{Line, Plot, Value, Values},
 };
-use egui::{Color32};
-use std::time::Instant;
+use egui::{Color32, plot};
 
 pub struct MathApp {
     func_str: String,
@@ -15,6 +14,7 @@ pub struct MathApp {
     num_interval: usize,
     resolution: usize,
     chart_manager: ChartManager,
+    bar_cache: Cache<Vec<Bar>>,
 }
 
 impl Default for MathApp {
@@ -26,6 +26,7 @@ impl Default for MathApp {
             num_interval: 100,
             resolution: 10000,
             chart_manager: ChartManager::new("x^2".to_string(), -10.0, 10.0, 100, 10000),
+            bar_cache: Cache::new_empty(),
         }
     }
 }
@@ -47,10 +48,13 @@ impl epi::App for MathApp {
             min_x,
             max_x,
             num_interval,
-            resolution: _,
+            resolution,
             chart_manager,
+            bar_cache,
         } = self;
-        let start = Instant::now();
+
+        // Note: This Instant implementation does not show microseconds when using wasm.
+        let start = instant::Instant::now();
 
         let min_x_total: f32 = -1000.0;
         let max_x_total: f32 = 1000.0;
@@ -91,6 +95,10 @@ impl epi::App for MathApp {
             ui.add(egui::Slider::new(num_interval, 1..=usize::MAX).text("Interval"));
         });
 
+
+        let update_back = chart_manager.do_update_back(func_str.clone(), *min_x, *max_x);
+        let update_front = chart_manager.do_update_front(*num_interval, *resolution);
+
         egui::CentralPanel::default().show(ctx, |ui| {
             if !parse_error.is_empty() {
                 ui.label(format!("Error: {}", parse_error));
@@ -99,10 +107,10 @@ impl epi::App for MathApp {
 
             let (filtered_data, rect_data, area) = chart_manager.update(
                 self.func_str.clone(),
-                self.min_x,
-                self.max_x,
-                self.num_interval,
-                self.resolution,
+                *min_x,
+                *max_x,
+                *num_interval,
+                *resolution,
             );
 
             let filtered_data_values = filtered_data
@@ -112,17 +120,39 @@ impl epi::App for MathApp {
 
             let curve = Line::new(Values::from_values(filtered_data_values)).color(Color32::RED);
 
-            let bars = rect_data
-                .iter()
-                .map(|(x, y)| Bar::new(*x, *y))
-                .collect();
-            let barchart = BarChart::new(bars).color(Color32::BLUE);
+            let bars: Vec<Bar> = match update_front {
+                true => {
+                    let bars: Vec<Bar> = rect_data
+                    .iter()
+                    .map(|(x, y)| Bar::new(*x, *y))
+                    .collect();
+                    
+                    bar_cache.set(bars.clone());
+                    bars
+                },
+                false => {
+                    if bar_cache.is_valid() {
+                        bar_cache.get().clone()
+                    } else {
+                        let bars: Vec<Bar> = rect_data
+                        .iter()
+                        .map(|(x, y)| Bar::new(*x, *y))
+                        .collect();
+                        
+                        bar_cache.set(bars.clone());
+                        bars
+                    }
+                },
+            };
+            let bar_chart = BarChart::new(bars).color(Color32::BLUE);
+            
+
             Plot::new("plot")
                 .view_aspect(1.0)
                 .include_y(0)
                 .show(ui, |plot_ui| {
                     plot_ui.line(curve);
-                    plot_ui.bar_chart(barchart);
+                    plot_ui.bar_chart(bar_chart);
                 });
 
             let duration = start.elapsed();