fixup and remove egui legend

TODO.md

@@ -7,7 +7,6 @@
 	- Prevent user from making too many function entries
 	- Display function errors as tooltips or a warning box (not preventing the display of the graph)
 	- Clone functions
-	- Better integration with egui's legend
 2. Smart display of graph
 	- Display of intersections between functions
 3. Allow constants in min/max integral input (like pi or euler's number)

src/function_entry.rs

@@ -378,10 +378,6 @@ impl FunctionEntry {
 					.collect();
 				debug_assert_eq!(data.len(), settings.plot_width + 1);
 				self.derivative_data = data;
-
-				unsafe {
-					assume(!self.derivative_data.is_empty());
-				}
 			}
 
 			if self.nth_derviative && self.nth_derivative_data.is_none() {
@@ -390,10 +386,6 @@ impl FunctionEntry {
 					.collect();
 				debug_assert_eq!(data.len(), settings.plot_width + 1);
 				self.nth_derivative_data = Some(data);
-
-				unsafe {
-					assume(self.nth_derivative_data.is_some());
-				}
 			}
 		}
 
@@ -407,9 +399,6 @@ impl FunctionEntry {
 				);
 				self.integral_data =
 					Some((data.iter().map(|(x, y)| Bar::new(*x, *y)).collect(), area));
-				unsafe {
-					assume(self.integral_data.is_some());
-				}
 			}
 		} else {
 			self.invalidate_integral();

src/math_app.rs

@@ -566,17 +566,13 @@ impl App for MathApp {
 
 				let available_width: usize = (ui.available_width() as usize) + 1; // Used in later logic
 				let width_changed = available_width != self.settings.plot_width;
-
-				if width_changed {
-					self.settings.plot_width = available_width;
-				}
+				self.settings.plot_width = available_width;
 
 				// Create and setup plot
 				Plot::new("plot")
 					.set_margin_fraction(Vec2::ZERO)
 					.data_aspect(1.0)
 					.include_y(0)
-					.legend(egui::plot::Legend::default())
 					.show(ui, |plot_ui| {
 						let bounds = plot_ui.plot_bounds();
 						let min_x: f64 = bounds.min()[0];