From e049038813bc38b2dbf9bbad9fd972dd99c12069 Mon Sep 17 00:00:00 2001
From: Simon Gardling <titaniumtown@gmail.com>
Date: Wed, 23 Feb 2022 15:37:49 -0500
Subject: [PATCH] progress

---
 TODO.md         |  1 -
 src/egui_app.rs | 24 +++++++++++++++++++-----
 src/main.rs     |  4 +++-
 src/misc.rs     |  6 ++++++
 4 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/TODO.md b/TODO.md
index c5f3875..df6cf28 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,4 +1,3 @@
 ## TODO:
 1. Port to [egui](https://github.com/emilk/egui)
-    - Reimplement testing the validity of functions.
     - Proper support for dynamic chart display size.
\ No newline at end of file
diff --git a/src/egui_app.rs b/src/egui_app.rs
index 468eb34..4c82b5a 100644
--- a/src/egui_app.rs
+++ b/src/egui_app.rs
@@ -1,8 +1,10 @@
+use core::num;
+
 use eframe::{egui, epi};
 use egui::{plot::{HLine, Line, Plot, Value, Values, Text}, Pos2};
 use crate::chart_manager::ChartManager;
 use meval::Expr;
-use crate::misc::{add_asterisks, Cache, Function};
+use crate::misc::{add_asterisks, Cache, Function, digits_precision, test_func};
 use egui::{Color32, ColorImage, Ui};
 use emath::Rect;
 use epaint::{Rounding, RectShape, Stroke};
@@ -56,6 +58,7 @@ impl epi::App for MathApp {
             chart_manager
         } = self;
 
+        let mut parse_error: String = "".to_string();
         egui::SidePanel::left("side_panel").show(ctx, |ui| {
             ui.heading("Side Panel");
 
@@ -63,6 +66,10 @@ impl epi::App for MathApp {
                 ui.label("Function: ");
                 ui.text_edit_singleline(func_str);
             });
+            let func_test_output = test_func(func_str.clone());
+            if func_test_output != "" {
+                parse_error = func_test_output;
+            }
 
             ui.add(egui::Slider::new(min_x, -1000.0..=1000.0).text("Min X"));
             ui.add(egui::Slider::new(max_x, *min_x..=1000.0).text("Max X"));
@@ -71,22 +78,29 @@ impl epi::App for MathApp {
         });
 
         egui::CentralPanel::default().show(ctx, |ui| {
+            if parse_error != "" {
+                ui.label(format!("Error: {}", parse_error));
+                return;
+            }
+
             let (filtered_data, rect_data, area) = chart_manager.update(self.func_str.clone(), self.min_x, self.max_x, self.num_interval, self.resolution);
 
             let filtered_data_values = filtered_data.iter().map(|(x, y)| Value::new(*x, *y)).collect();
 
             let curve = Line::new(Values::from_values(filtered_data_values)).color(Color32::RED);
+
             let bars = rect_data.iter().map(|(_, x2, y)| Bar::new(*x2, *y)).collect();
             let barchart = BarChart::new(bars).color(Color32::BLUE);
-            
-            // ui.label("Graph:");
-            ui.label(format!("Area: {:.10}", area));
+
+            ui.label(format!("Area: {}", digits_precision(area, 8)));
             Plot::new("plot")
                 .view_aspect(1.0)
                 .include_y(0)
                 .show(ui, |plot_ui| {
                     plot_ui.line(curve);
-                    plot_ui.bar_chart(barchart);
+                    if self.num_interval > 0 {
+                        plot_ui.bar_chart(barchart);
+                    }
             });
         });
 
diff --git a/src/main.rs b/src/main.rs
index 5aa526e..e1e738c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,8 +1,10 @@
-use eframe::{epi, egui};
 mod egui_app;
+
+// These 2 are needed for rust-analyzer to work in vscode.
 mod misc;
 mod chart_manager;
 
+// For running the program natively! (Because why not?)
 #[cfg(not(target_arch = "wasm32"))]
 fn main() {
     let app = egui_app::MathApp::default();
diff --git a/src/misc.rs b/src/misc.rs
index 7f6a6ec..18990ca 100644
--- a/src/misc.rs
+++ b/src/misc.rs
@@ -107,6 +107,12 @@ pub fn test_func(function_string: String) -> String {
     "".to_string()
 }
 
+// Rounds f64 to specific number of digits
+pub fn digits_precision(x: f64, digits: usize) -> f64 {
+    let large_number: f64 = (10.0 as f64).powf(digits as f64);
+    (x * large_number).round() / large_number
+}
+
 pub struct Function {
     function: Box<dyn Fn(f64) -> f64>,
     func_str: String,