added public properties

src/lib.rs

@@ -1,20 +1,72 @@
-use egui::{Response, Sense, Ui, Vec2, Widget};
+use egui::{Align2, Color32, Response, Sense, Stroke, Ui, Vec2, Widget};
+
+pub enum LabelPosition {
+    Top,
+    Bottom,
+    Left,
+    Right,
+}
 
 pub struct Knob<'a> {
     value: &'a mut f32,
     min: f32,
     max: f32,
+    size: f32,
+    font_size: f32,
+    stroke_width: f32,
+    knob_color: Color32,
+    line_color: Color32,
+    label: Option<String>,
+    label_position: LabelPosition,
 }
 
 impl<'a> Knob<'a> {
     pub fn new(value: &'a mut f32, min: f32, max: f32) -> Self {
-        Self { value, min, max }
+        Self {
+            value,
+            min,
+            max,
+            size: 40.0,
+            font_size: 12.0,
+            stroke_width: 2.0,
+            knob_color: Color32::GRAY,
+            line_color: Color32::GRAY,
+            label: None,
+            label_position: LabelPosition::Bottom,
+        }
+    }
+
+    pub fn with_size(mut self, size: f32) -> Self {
+        self.size = size;
+        self
+    }
+
+    pub fn with_font_size(mut self, size: f32) -> Self {
+        self.font_size = size;
+        self
+    }
+
+    pub fn with_stroke_width(mut self, width: f32) -> Self {
+        self.stroke_width = width;
+        self
+    }
+
+    pub fn with_colors(mut self, knob_color: Color32, line_color: Color32) -> Self {
+        self.knob_color = knob_color;
+        self.line_color = line_color;
+        self
+    }
+
+    pub fn with_label(mut self, label: impl Into<String>, position: LabelPosition) -> Self {
+        self.label = Some(label.into());
+        self.label_position = position;
+        self
     }
 }
 
 impl Widget for Knob<'_> {
     fn ui(self, ui: &mut Ui) -> Response {
-        let desired_size = Vec2::splat(40.0);
+        let desired_size = Vec2::splat(self.size);
         let (rect, response) = ui.allocate_exact_size(desired_size, Sense::drag());
 
         if response.dragged() {
@@ -28,11 +80,60 @@ impl Widget for Knob<'_> {
         let center = rect.center();
         let radius = rect.width() / 2.0;
         let angle = (*self.value - self.min) / (self.max - self.min) * std::f32::consts::PI * 1.5
-            - std::f32::consts::PI * 0.75;
+            - std::f32::consts::PI;
 
-        painter.circle_stroke(center, radius, egui::Stroke::new(2.0, ui.visuals().text_color()));
+        // Draw knob circle
+        painter.circle_stroke(
+            center,
+            radius,
+            Stroke::new(self.stroke_width, self.knob_color),
+        );
+
+        // Draw pointer line
         let pointer = center + Vec2::angled(angle) * (radius * 0.7);
-        painter.line_segment([center, pointer], egui::Stroke::new(3.0, ui.visuals().text_color()));
+        painter.line_segment(
+            [center, pointer],
+            Stroke::new(self.stroke_width * 1.5, self.line_color),
+        );
+
+        if let Some(label) = self.label {
+            let label_text = format!("{label}: {:.2}", self.value);
+
+            let font_id = egui::FontId::proportional(self.font_size);
+            let text_size = ui
+                .painter()
+                .layout(
+                    label_text.clone(),
+                    font_id.clone(),
+                    Color32::WHITE,
+                    f32::INFINITY,
+                )
+                .size();
+
+            let label_offset = 12.0;
+            let label_pos = match self.label_position {
+                LabelPosition::Top => {
+                    center + Vec2::new(-text_size.x / 2.0, -radius - label_offset - text_size.y)
+                }
+                LabelPosition::Bottom => {
+                    center + Vec2::new(-text_size.x / 2.0, radius + label_offset)
+                }
+                LabelPosition::Left => {
+                    center + Vec2::new(-radius - label_offset - text_size.x, -text_size.y / 2.0)
+                }
+                LabelPosition::Right => {
+                    center + Vec2::new(radius + label_offset, -text_size.y / 2.0)
+                }
+            };
+
+            ui.painter().text(
+                label_pos,
+                Align2::LEFT_TOP,
+                label_text,
+                font_id,
+                Color32::WHITE,
+            );
+        }
 
         response
     }