chore: restructured the project

docs: added contributing guidelines and updated rreadme

.gitignore

@@ -1,2 +1,14 @@
+# Rust
 /target
-/examples/target
+/examples/target
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db

CHANGELOG.md

@@ -2,6 +2,16 @@
 
 All notable changes to this project will be documented in this file.
 
+## [0.3.5] - 2025-07-15
+
+### 🛠 Maintenance
+
+- Restructured the project
+
+### 📚 Documentation
+
+- Updated readme, added contributing guidelines
+
 ## [0.3.4] - 2025-07-15
 
 ### 🛠 Maintenance

CONTRIBUTING.md

@@ -0,0 +1,48 @@
+# Contributing to egui_knob
+
+## Getting Started
+
+1. Fork the repository
+2. Clone your fork: `git clone https://github.com/YOUR_USERNAME/egui_knob.git`
+3. Create a new branch: `git checkout -b feature/your-feature-name`
+4. Make your changes
+5. Test your changes
+6. Commit your changes
+7. Push to the branch: `git push origin feature/your-feature-name`
+8. Submit a pull request
+
+## Development
+
+### Building
+
+```bash
+cargo build
+```
+
+## Running demo app
+
+```bash
+cargo run --example example_knob
+```
+
+## Code Style
+
+- Follow Rust standard formatting (use `cargo fmt`)
+- Write clear, descriptive commit messages
+- Add documentation for public APIs
+- Keep changes focused and atomic
+
+## Pull Request Guidelines
+
+- Add examples for new features
+- Keep PRs focused on a single feature or fix
+- Reference any related issues
+
+## Reporting Issues
+
+When reporting issues, please include:
+- A clear description of the problem
+- Steps to reproduce
+- Expected vs actual behavior
+- Your environment (OS, Rust version)
+- Minimal code example if applicable

Cargo.lock

@@ -869,7 +869,7 @@ dependencies = [
 
 [[package]]
 name = "egui_knob"
-version = "0.3.4"
+version = "0.3.5"
 dependencies = [
  "eframe",
  "egui",

Cargo.toml

@@ -1,10 +1,12 @@
 [package]
 name = "egui_knob"
-version = "0.3.4"
+version = "0.3.5"
 edition = "2024"
+authors = ["Daniel Dada"]
 description = "A simple knob widget for egui"
 homepage = "https://github.com/obsqrbtz/egui_knob"
 repository = "https://github.com/obsqrbtz/egui_knob"
+documentation = "https://docs.rs/egui_knob"
 readme = "README.md"
 license = "MIT"
 keywords = ["egui", "ui", "widget", "knob", "range"]

README.md

@@ -1,18 +1,23 @@
 # egui_knob
 
-![Crates.io Version](https://img.shields.io/crates/v/egui_knob)
+[![Crates.io](https://img.shields.io/crates/v/egui_knob)](https://crates.io/crates/egui_knob)
+[![Documentation](https://docs.rs/egui_knob/badge.svg)](https://docs.rs/egui_knob)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](LICENSE)
 
-Simple knob widget for egui.
+A simple, customizable knob widget for egui.
 
 ![Knob Widget Screenshot](scrot.png)
 
 ## Features
 
-- Adjustable size, font size, and stroke width.
+- Adjustable size, font size, and stroke width
-- Customizable colors for the knob, indicator and text.
+- Customizable colors for the knob, indicator, and text
-- Label positions (Top, Bottom, Left, Right).
+- Label positions (Top, Bottom, Left, Right)
-- Label formatting.
+- Custom label formatting
-- Two styles: Wiper and Dot.
+- Two visual styles: Wiper and Dot
+- Configurable sweep range
+- Background arc with filled segments
+- Adjustable drag sensitivity
 
 ## Installation
 
@@ -22,14 +27,16 @@ To use the Knob widget in your project, add the following to your `Cargo.toml`:
 [dependencies]
 egui = "0.33"
 eframe = "0.33"
-egui_knob = "0.3.4"
+egui_knob = "0.3.5"
 ```
 
-## Usage example
+## Usage
+
+### Basic Example
 
 ```rust
 use egui_knob::{Knob, KnobStyle, LabelPosition};
-use eframe::{egui};
+use eframe::egui;
 
 struct KnobApp {
     value: f32,
@@ -56,12 +63,55 @@ impl eframe::App for KnobApp {
     }
 }
 
-fn main() {
+fn main() -> eframe::Result<()> {
-    let options = eframe::NativeOptions::default();
     eframe::run_native(
-        "Minimal",
+        "Knob Example",
-        options,
+        eframe::NativeOptions::default(),
-        Box::new(|_cc| Ok(Box::new(KnobApp::default()) as Box<dyn eframe::App>)),
+        Box::new(|_cc| Ok(Box::new(KnobApp::default()))),
-    ).unwrap();
+    )
 }
 ```
+
+### Advanced Examples
+
+#### Custom Sweep Range
+```rust
+// 270° sweep starting from the left (9 o'clock position)
+Knob::new(&mut value, 0.0, 100.0, KnobStyle::Wiper)
+    .with_sweep_range(0.25, 0.75)
+    .with_label("Gain", LabelPosition::Bottom);
+```
+
+#### Multi-Turn Knob
+```rust
+// 2.5 full rotations
+Knob::new(&mut value, 0.0, 1.0, KnobStyle::Dot)
+    .with_sweep_range(0.0, 2.5);
+```
+
+#### Stepped Values
+```rust
+// Snap to 0.1 increments
+Knob::new(&mut value, 0.0, 1.0, KnobStyle::Wiper)
+    .with_step(Some(0.1))
+    .with_label_format(|v| format!("{:.1}", v));
+```
+
+#### Custom Formatting
+```rust
+// Display as percentage
+Knob::new(&mut value, 0.0, 1.0, KnobStyle::Wiper)
+    .with_label_format(|v| format!("{:.0}%", v * 100.0));
+```
+
+## Running demo app
+
+```bash
+cargo run --example example_knob
+```
+
+Demo app is available at [examples/example_knob.rs](examples/example_knob.rs).
+
+## Contributing
+
+Contributions are welcome. Feel free to open an issue or submit a PR.

examples/example_knob.rs

@@ -2,9 +2,16 @@ use eframe::egui;
 use egui_knob::{Knob, KnobStyle, LabelPosition};
 
 fn main() -> eframe::Result<()> {
+    let options = eframe::NativeOptions {
+        viewport: egui::ViewportBuilder::default()
+            .with_inner_size([800.0, 600.0])
+            .with_title("egui_knob demo"),
+        ..Default::default()
+    };
+
     eframe::run_native(
         "egui_knob demo",
-        eframe::NativeOptions::default(),
+        options,
         Box::new(|_cc| Ok(Box::new(KnobDemo::default()))),
     )
 }
@@ -36,24 +43,27 @@ impl Default for KnobDemo {
 impl eframe::App for KnobDemo {
     fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
         egui::CentralPanel::default().show(ctx, |ui| {
-            ui.heading("egui-knob example");
+            ui.heading("egui_knob demo");
             ui.separator();
 
             ui.horizontal(|ui| {
-                ui.checkbox(&mut self.show_bg_arc, "Show background arc");
+                ui.label("Global Settings:");
-                ui.checkbox(&mut self.show_filled, "Show filled segment");
+                ui.checkbox(&mut self.show_bg_arc, "Background arc");
-                ui.checkbox(&mut self.use_step, "Enable step (0.1)");
+                ui.checkbox(&mut self.show_filled, "Filled segment");
+                ui.checkbox(&mut self.use_step, "Step (0.02)");
             });
 
             ui.horizontal(|ui| {
-                ui.label("Knob Colors:");
+                ui.label("Color Theme:");
                 ui.color_edit_button_srgba(&mut self.knob_color);
+                ui.label("Knob");
                 ui.color_edit_button_srgba(&mut self.line_color);
+                ui.label("Indicator");
                 ui.color_edit_button_srgba(&mut self.text_color);
+                ui.label("Text");
             });
 
             ui.separator();
-            ui.label("👇 Scroll or drag knobs to interact:");
 
             ui.add_space(10.0);
             egui::Grid::new("knob_grid")
@@ -78,7 +88,7 @@ impl eframe::App for KnobDemo {
                                 .with_background_arc(self.show_bg_arc)
                                 .with_show_filled_segments(self.show_filled)
                                 .with_colors(self.knob_color, self.line_color, self.text_color)
-                                .with_step(self.use_step.then_some(0.1));
+                                .with_step(self.use_step.then_some(0.02));
 
                             if *label == "Wiper, Sweep" {
                                 knob = knob.with_sweep_range(0.25, 0.75).with_size(50.0);

src/config.rs

@@ -0,0 +1,41 @@
+use crate::style::{KnobColors, KnobStyle, LabelPosition};
+
+pub struct KnobConfig {
+    pub(crate) size: f32,
+    pub(crate) font_size: f32,
+    pub(crate) stroke_width: f32,
+    pub(crate) colors: KnobColors,
+    pub(crate) label: Option<String>,
+    pub(crate) label_position: LabelPosition,
+    pub(crate) style: KnobStyle,
+    pub(crate) label_offset: f32,
+    pub(crate) label_format: Box<dyn Fn(f32) -> String>,
+    pub(crate) step: Option<f32>,
+    pub(crate) drag_sensitivity: f32,
+    pub(crate) show_background_arc: bool,
+    pub(crate) show_filled_segments: bool,
+    pub(crate) min_angle: f32,
+    pub(crate) max_angle: f32,
+}
+
+impl KnobConfig {
+    pub fn new(style: KnobStyle) -> Self {
+        Self {
+            size: 40.0,
+            font_size: 12.0,
+            stroke_width: 2.0,
+            colors: KnobColors::default(),
+            label: None,
+            label_position: LabelPosition::Bottom,
+            style,
+            label_offset: 1.0,
+            label_format: Box::new(|v| format!("{:.2}", v)),
+            step: None,
+            min_angle: -std::f32::consts::PI,
+            max_angle: std::f32::consts::PI * 0.5,
+            drag_sensitivity: 0.005,
+            show_background_arc: true,
+            show_filled_segments: true,
+        }
+    }
+}

src/lib.rs

@@ -1,412 +1,7 @@
-use core::f32;
+mod config;
+mod render;
+mod style;
+mod widget;
 
-use egui::{Align2, Color32, Rect, Response, Sense, Stroke, Ui, Vec2, Widget};
+pub use style::{KnobStyle, LabelPosition};
-
+pub use widget::Knob;
-/// Position of the label relative to the knob
-pub enum LabelPosition {
-    Top,
-    Bottom,
-    Left,
-    Right,
-}
-
-/// Visual style of the knob indicator
-#[derive(Clone, Copy)] // <--- add this!
-pub enum KnobStyle {
-    /// A line extending from the center to the edge
-    Wiper,
-    /// A dot on the edge of the knob
-    Dot,
-}
-
-/// A circular knob widget for egui that can be dragged to change a value
-///
-/// # Example
-/// ```
-/// let mut value = 0.5;
-/// Knob::new(&mut value, 0.0, 1.0, KnobStyle::Wiper)
-///     .with_size(50.0)
-///     .with_label("Volume", LabelPosition::Bottom)
-///     .with_step(0.1);
-/// ```
-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,
-    text_color: Color32,
-    label: Option<String>,
-    label_position: LabelPosition,
-    style: KnobStyle,
-    label_offset: f32,
-    label_format: Box<dyn Fn(f32) -> String>,
-    step: Option<f32>,
-    drag_sensitivity: f32,
-    show_background_arc: bool,
-    show_filled_segments: bool,
-
-    /// Minimum angle in radians.  
-    /// Specifies the lower bound of the knob's rotation.  
-    /// Expected range: 0.0 to TAU. Values outside this range are allowed if your use case requires it.
-    min_angle: f32,
-
-    /// Maximum angle in radians.  
-    /// Specifies the upper bound of the knob's rotation.
-    /// Can be any value > `min_angle`
-    /// range `max_angle` - `min_angle` > TAU is allowed but will induce multi-turn
-    max_angle: f32,
-}
-
-impl<'a> Knob<'a> {
-    /// Creates a new knob widget
-    ///
-    /// # Arguments
-    /// * `value` - Mutable reference to the value controlled by the knob
-    /// * `min` - Minimum value
-    /// * `max` - Maximum value
-    /// * `style` - Visual style of the knob indicator
-    pub fn new(value: &'a mut f32, min: f32, max: f32, style: KnobStyle) -> Self {
-        Self {
-            value,
-            min,
-            max,
-            size: 40.0,
-            font_size: 12.0,
-            stroke_width: 2.0,
-            knob_color: Color32::GRAY,
-            line_color: Color32::GRAY,
-            text_color: Color32::WHITE,
-            label: None,
-            label_position: LabelPosition::Bottom,
-            style,
-            label_offset: 1.0,
-            label_format: Box::new(|v| format!("{:.2}", v)),
-            step: None,
-
-            // Hardcode those two angles to ENSURE backward compatibility
-            min_angle: -std::f32::consts::PI,
-            max_angle: std::f32::consts::PI * 0.5,
-            drag_sensitivity: 0.005,
-            show_background_arc: true,
-            show_filled_segments: true,
-        }
-    }
-
-    /// Sets the angular sweep range of the knob
-    ///
-    /// This controls where the knob starts and how far it can rotate. By default,
-    /// knobs start at the left (180°) and sweep 270° clockwise to bottom.
-    ///
-    /// # Arguments
-    /// * `start_angle_normalized` - Starting position as fraction of full circle:
-    ///   - `0.0` = bottom (6 o'clock)
-    ///   - `0.25` = left (9 o'clock)
-    ///   - `0.5` = top (12 o'clock)
-    ///   - `0.75` = right (3 o'clock)
-    /// * `range` - How far the knob can sweep as fraction of full circle:
-    ///   - `0.25` = quarter turn (90°)
-    ///   - `0.5` = half turn (180°)
-    ///   - `0.75` = three-quarter turn (270°)
-    ///   - `1.0` = full turn (360°)
-    ///   - Values > 1.0 create multi-turn knobs
-    ///   - Negative values are clamped to 0.0
-    ///
-    /// Note: the start angle is offset by PI/2 so that `0.0` is at the bottom (6 o'clock)
-    pub fn with_sweep_range(mut self, start_angle_normalized: f32, range: f32) -> Self {
-        if start_angle_normalized.is_nan() || range.is_nan() {
-            return self;
-        }
-
-        self.min_angle =
-            start_angle_normalized.rem_euclid(1.) * f32::consts::TAU + f32::consts::PI / 2.;
-
-        // A range of 1. represent a full turn
-        self.max_angle = self.min_angle + range.max(0.) * f32::consts::TAU;
-        self
-    }
-
-    /// Sets the size of the knob
-    pub fn with_size(mut self, size: f32) -> Self {
-        self.size = size;
-        self
-    }
-
-    /// Sets the font size for the label
-    pub fn with_font_size(mut self, size: f32) -> Self {
-        self.font_size = size;
-        self
-    }
-
-    /// Sets the stroke width for the knob's outline and indicator
-    pub fn with_stroke_width(mut self, width: f32) -> Self {
-        self.stroke_width = width;
-        self
-    }
-
-    /// Sets the colors for different parts of the knob
-    ///
-    /// # Arguments
-    /// * `knob_color` - Color of the knob's outline
-    /// * `line_color` - Color of the indicator
-    /// * `text_color` - Color of the label text
-    pub fn with_colors(
-        mut self,
-        knob_color: Color32,
-        line_color: Color32,
-        text_color: Color32,
-    ) -> Self {
-        self.knob_color = knob_color;
-        self.line_color = line_color;
-        self.text_color = text_color;
-        self
-    }
-
-    /// Adds a label to the knob
-    ///
-    /// # Arguments
-    /// * `label` - Text to display
-    /// * `position` - Position of the label relative to the knob
-    pub fn with_label(mut self, label: impl Into<String>, position: LabelPosition) -> Self {
-        self.label = Some(label.into());
-        self.label_position = position;
-        self
-    }
-
-    /// Sets the spacing between the knob and its label
-    pub fn with_label_offset(mut self, offset: f32) -> Self {
-        self.label_offset = offset;
-        self
-    }
-
-    /// Sets a custom format function for displaying the value
-    ///
-    /// # Example
-    /// ```
-    /// # let mut value = 0.5;
-    /// Knob::new(&mut value, 0.0, 1.0, KnobStyle::Wiper)
-    ///     .with_label_format(|v| format!("{:.1}%", v * 100.0));
-    /// ```
-    pub fn with_label_format(mut self, format: impl Fn(f32) -> String + 'static) -> Self {
-        self.label_format = Box::new(format);
-        self
-    }
-
-    /// Sets the step size for value changes
-    ///
-    /// When set, the value will snap to discrete steps as the knob is dragged.
-    pub fn with_step(mut self, step: Option<f32>) -> Self {
-        self.step = step;
-        self
-    }
-    /// Shows the background arc showing full range
-    pub fn with_background_arc(mut self, enabled: bool) -> Self {
-        self.show_background_arc = enabled;
-        self
-    }
-    /// Shows filled range on the background arc
-    pub fn with_show_filled_segments(mut self, enabled: bool) -> Self {
-        self.show_filled_segments = enabled;
-        self
-    }
-    // Private
-    fn compute_angle(&self) -> f32 {
-        if self.min == self.max || self.value.is_nan() {
-            self.min_angle
-        } else {
-            self.min_angle
-                + (*self.value - self.min) / (self.max - self.min)
-                    * (self.max_angle - self.min_angle)
-        }
-    }
-}
-
-impl Widget for Knob<'_> {
-    fn ui(self, ui: &mut Ui) -> Response {
-        if self.value.is_nan() {
-            *self.value = self.min;
-        }
-
-        let knob_size = Vec2::splat(self.size);
-
-        let label_size = if let Some(label) = &self.label {
-            let font_id = egui::FontId::proportional(self.font_size);
-            let max_text = format!("{}: {}", label, (self.label_format)(self.max));
-            ui.painter()
-                .layout(max_text, font_id, Color32::WHITE, f32::INFINITY)
-                .size()
-        } else {
-            Vec2::ZERO
-        };
-
-        let label_padding = 2.0;
-
-        let adjusted_size = match self.label_position {
-            LabelPosition::Top | LabelPosition::Bottom => Vec2::new(
-                knob_size.x.max(label_size.x + label_padding * 2.0),
-                knob_size.y + label_size.y + label_padding * 2.0 + self.label_offset,
-            ),
-            LabelPosition::Left | LabelPosition::Right => Vec2::new(
-                knob_size.x + label_size.x + label_padding * 2.0 + self.label_offset,
-                knob_size.y.max(label_size.y + label_padding * 2.0),
-            ),
-        };
-
-        let (rect, mut response) = ui.allocate_exact_size(adjusted_size, Sense::drag());
-
-        if response.dragged() {
-            let delta = response.drag_delta().y;
-            let range = self.max - self.min;
-            let step = self.step.unwrap_or(range * self.drag_sensitivity);
-            let new_value = (*self.value - delta * step).clamp(self.min, self.max);
-
-            *self.value = if let Some(step) = self.step {
-                let steps = ((new_value - self.min) / step).round();
-                (self.min + steps * step).clamp(self.min, self.max)
-            } else {
-                new_value
-            };
-
-            if self.value.is_nan() {
-                *self.value = self.min;
-            }
-
-            response.mark_changed();
-        }
-
-        let painter = ui.painter();
-        let knob_rect = match self.label_position {
-            LabelPosition::Left => {
-                Rect::from_min_size(rect.right_top() + Vec2::new(-knob_size.x, 0.0), knob_size)
-            }
-            LabelPosition::Right => Rect::from_min_size(rect.left_top(), knob_size),
-            LabelPosition::Top => Rect::from_min_size(
-                rect.left_bottom() + Vec2::new((rect.width() - knob_size.x) / 2.0, -knob_size.y),
-                knob_size,
-            ),
-            LabelPosition::Bottom => Rect::from_min_size(
-                rect.left_top() + Vec2::new((rect.width() - knob_size.x) / 2.0, 0.0),
-                knob_size,
-            ),
-        };
-
-        let center = knob_rect.center();
-        let radius = knob_size.x / 2.0;
-        let angle = self.compute_angle();
-        let knob_hovered = response.hovered();
-        let knob_color = if knob_hovered {
-            self.knob_color.linear_multiply(1.2)
-        } else {
-            self.knob_color
-        };
-
-        painter.circle_stroke(center, radius, Stroke::new(self.stroke_width, knob_color));
-
-        // Background arc (indicating full range)
-        if self.show_background_arc {
-            let arc_start = self.min_angle;
-            let arc_end = self.max_angle;
-            let segments = 64;
-            let arc_color = self.knob_color.gamma_multiply(0.5); // dimmed background arc
-            let arc_radius = radius * 0.8;
-            let mut points = Vec::with_capacity(segments + 1);
-
-            for i in 0..=segments {
-                let t = i as f32 / segments as f32;
-                let angle = arc_start + (arc_end - arc_start) * t;
-                let pos = center + Vec2::angled(angle) * arc_radius;
-                points.push(pos);
-            }
-
-            painter.add(egui::Shape::line(
-                points,
-                Stroke::new(self.stroke_width, arc_color),
-            ));
-
-            // Filled part when background arc is enabled
-            if self.show_filled_segments {
-                let filled_segments = (segments as f32
-                    * ((*self.value - self.min) / (self.max - self.min)).clamp(0.0, 1.0))
-                    as usize;
-
-                let mut fill_points = Vec::with_capacity(filled_segments + 1);
-                for i in 0..=filled_segments {
-                    let t = i as f32 / segments as f32;
-                    let angle = arc_start + (arc_end - arc_start) * t;
-                    let pos = center + Vec2::angled(angle) * arc_radius;
-                    fill_points.push(pos);
-                }
-
-                painter.add(egui::Shape::line(
-                    fill_points,
-                    Stroke::new(self.stroke_width, self.line_color),
-                ));
-            }
-        }
-
-        match self.style {
-            KnobStyle::Wiper => {
-                let pointer = center + Vec2::angled(angle) * (radius * 0.7);
-                painter.line_segment(
-                    [center, pointer],
-                    Stroke::new(self.stroke_width * 1.5, self.line_color),
-                );
-            }
-            KnobStyle::Dot => {
-                let dot_pos = center + Vec2::angled(angle) * (radius * 0.7);
-                painter.circle_filled(dot_pos, self.stroke_width * 1.5, self.line_color);
-            }
-        }
-
-        if let Some(label) = self.label {
-            let label_text = format!("{}: {}", label, (self.label_format)(*self.value));
-            let font_id = egui::FontId::proportional(self.font_size);
-
-            let label_padding = 2.0;
-
-            let (label_pos, alignment) = match self.label_position {
-                LabelPosition::Top => (
-                    Vec2::new(
-                        rect.center().x,
-                        rect.min.y - self.label_offset + label_padding,
-                    ),
-                    Align2::CENTER_TOP,
-                ),
-                LabelPosition::Bottom => (
-                    Vec2::new(rect.center().x, rect.max.y + self.label_offset),
-                    Align2::CENTER_BOTTOM,
-                ),
-                LabelPosition::Left => (
-                    Vec2::new(rect.min.x - self.label_offset, rect.center().y),
-                    Align2::LEFT_CENTER,
-                ),
-                LabelPosition::Right => (
-                    Vec2::new(rect.max.x + self.label_offset, rect.center().y),
-                    Align2::RIGHT_CENTER,
-                ),
-            };
-
-            ui.painter().text(
-                label_pos.to_pos2(),
-                alignment,
-                label_text,
-                font_id,
-                self.text_color,
-            );
-
-            if response.hovered() {
-                response
-                    .clone()
-                    .on_hover_text((self.label_format)(*self.value));
-            }
-        }
-
-        // Draw the bounding rect
-        //painter.rect_stroke(rect, 0.0, Stroke::new(1.0, Color32::RED));
-
-        response
-    }
-}

src/render.rs

@@ -0,0 +1,196 @@
+use egui::{Align2, Color32, Painter, Pos2, Rect, Stroke, Ui, Vec2};
+
+use crate::config::KnobConfig;
+use crate::style::{KnobStyle, LabelPosition};
+
+pub(crate) struct KnobRenderer<'a> {
+    config: &'a KnobConfig,
+    value: f32,
+    min: f32,
+    max: f32,
+}
+
+impl<'a> KnobRenderer<'a> {
+    pub fn new(config: &'a KnobConfig, value: f32, min: f32, max: f32) -> Self {
+        Self {
+            config,
+            value,
+            min,
+            max,
+        }
+    }
+
+    pub fn compute_angle(&self) -> f32 {
+        if self.min == self.max || self.value.is_nan() {
+            self.config.min_angle
+        } else {
+            self.config.min_angle
+                + (self.value - self.min) / (self.max - self.min)
+                    * (self.config.max_angle - self.config.min_angle)
+        }
+    }
+
+    pub fn render_knob(&self, painter: &Painter, center: Pos2, radius: f32, hovered: bool) {
+        let knob_color = if hovered {
+            self.config.colors.knob_color.linear_multiply(1.2)
+        } else {
+            self.config.colors.knob_color
+        };
+
+        painter.circle_stroke(
+            center,
+            radius,
+            Stroke::new(self.config.stroke_width, knob_color),
+        );
+
+        if self.config.show_background_arc {
+            self.render_background_arc(painter, center, radius);
+        }
+
+        let angle = self.compute_angle();
+        match self.config.style {
+            KnobStyle::Wiper => {
+                let pointer = center + Vec2::angled(angle) * (radius * 0.7);
+                painter.line_segment(
+                    [center, pointer],
+                    Stroke::new(
+                        self.config.stroke_width * 1.5,
+                        self.config.colors.line_color,
+                    ),
+                );
+            }
+            KnobStyle::Dot => {
+                let dot_pos = center + Vec2::angled(angle) * (radius * 0.7);
+                painter.circle_filled(
+                    dot_pos,
+                    self.config.stroke_width * 1.5,
+                    self.config.colors.line_color,
+                );
+            }
+        }
+    }
+
+    fn render_background_arc(&self, painter: &Painter, center: Pos2, radius: f32) {
+        let arc_start = self.config.min_angle;
+        let arc_end = self.config.max_angle;
+        let segments = 64;
+        let arc_color = self.config.colors.knob_color.gamma_multiply(0.5);
+        let arc_radius = radius * 0.8;
+
+        let mut points = Vec::with_capacity(segments + 1);
+        for i in 0..=segments {
+            let t = i as f32 / segments as f32;
+            let angle = arc_start + (arc_end - arc_start) * t;
+            let pos = center + Vec2::angled(angle) * arc_radius;
+            points.push(pos);
+        }
+
+        painter.add(egui::Shape::line(
+            points,
+            Stroke::new(self.config.stroke_width, arc_color),
+        ));
+
+        if self.config.show_filled_segments {
+            let filled_segments = (segments as f32
+                * ((self.value - self.min) / (self.max - self.min)).clamp(0.0, 1.0))
+                as usize;
+
+            let mut fill_points = Vec::with_capacity(filled_segments + 1);
+            for i in 0..=filled_segments {
+                let t = i as f32 / segments as f32;
+                let angle = arc_start + (arc_end - arc_start) * t;
+                let pos = center + Vec2::angled(angle) * arc_radius;
+                fill_points.push(pos);
+            }
+
+            painter.add(egui::Shape::line(
+                fill_points,
+                Stroke::new(self.config.stroke_width, self.config.colors.line_color),
+            ));
+        }
+    }
+
+    pub fn render_label(&self, ui: &Ui, rect: Rect) {
+        if let Some(label) = &self.config.label {
+            let label_text = format!("{}: {}", label, (self.config.label_format)(self.value));
+            let font_id = egui::FontId::proportional(self.config.font_size);
+            let label_padding = 2.0;
+
+            let (label_pos, alignment) = match self.config.label_position {
+                LabelPosition::Top => (
+                    Vec2::new(
+                        rect.center().x,
+                        rect.min.y - self.config.label_offset + label_padding,
+                    ),
+                    Align2::CENTER_TOP,
+                ),
+                LabelPosition::Bottom => (
+                    Vec2::new(rect.center().x, rect.max.y + self.config.label_offset),
+                    Align2::CENTER_BOTTOM,
+                ),
+                LabelPosition::Left => (
+                    Vec2::new(rect.min.x - self.config.label_offset, rect.center().y),
+                    Align2::LEFT_CENTER,
+                ),
+                LabelPosition::Right => (
+                    Vec2::new(rect.max.x + self.config.label_offset, rect.center().y),
+                    Align2::RIGHT_CENTER,
+                ),
+            };
+
+            ui.painter().text(
+                label_pos.to_pos2(),
+                alignment,
+                label_text,
+                font_id,
+                self.config.colors.text_color,
+            );
+        }
+    }
+
+    pub fn calculate_size(&self, ui: &Ui) -> Vec2 {
+        let knob_size = Vec2::splat(self.config.size);
+
+        let label_size = if let Some(label) = &self.config.label {
+            let font_id = egui::FontId::proportional(self.config.font_size);
+            let max_text = format!("{}: {}", label, (self.config.label_format)(self.max));
+            ui.painter()
+                .layout(max_text, font_id, Color32::WHITE, f32::INFINITY)
+                .size()
+        } else {
+            Vec2::ZERO
+        };
+
+        let label_padding = 2.0;
+
+        match self.config.label_position {
+            LabelPosition::Top | LabelPosition::Bottom => Vec2::new(
+                knob_size.x.max(label_size.x + label_padding * 2.0),
+                knob_size.y + label_size.y + label_padding * 2.0 + self.config.label_offset,
+            ),
+            LabelPosition::Left | LabelPosition::Right => Vec2::new(
+                knob_size.x + label_size.x + label_padding * 2.0 + self.config.label_offset,
+                knob_size.y.max(label_size.y + label_padding * 2.0),
+            ),
+        }
+    }
+
+    pub fn calculate_knob_rect(&self, rect: Rect) -> Rect {
+        let knob_size = Vec2::splat(self.config.size);
+
+        match self.config.label_position {
+            LabelPosition::Left => {
+                Rect::from_min_size(rect.right_top() + Vec2::new(-knob_size.x, 0.0), knob_size)
+            }
+            LabelPosition::Right => Rect::from_min_size(rect.left_top(), knob_size),
+            LabelPosition::Top => Rect::from_min_size(
+                rect.left_bottom() + Vec2::new((rect.width() - knob_size.x) / 2.0, -knob_size.y),
+                knob_size,
+            ),
+            LabelPosition::Bottom => Rect::from_min_size(
+                rect.left_top() + Vec2::new((rect.width() - knob_size.x) / 2.0, 0.0),
+                knob_size,
+            ),
+        }
+    }
+}

src/style.rs

@@ -0,0 +1,44 @@
+use egui::Color32;
+
+/// Visual style of the knob indicator
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum KnobStyle {
+    /// A line extending from the center to the edge
+    Wiper,
+    /// A dot on the edge of the knob
+    Dot,
+}
+
+/// Position of the label relative to the knob
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum LabelPosition {
+    /// Label appears above the knob
+    Top,
+    /// Label appears below the knob
+    Bottom,
+    /// Label appears to the left of the knob
+    Left,
+    /// Label appears to the right of the knob
+    Right,
+}
+
+/// Color configuration for the knob widget
+#[derive(Debug, Clone, Copy)]
+pub struct KnobColors {
+    /// Color of the knob's outline
+    pub knob_color: Color32,
+    /// Color of the indicator (wiper or dot)
+    pub line_color: Color32,
+    /// Color of the label text
+    pub text_color: Color32,
+}
+
+impl Default for KnobColors {
+    fn default() -> Self {
+        Self {
+            knob_color: Color32::GRAY,
+            line_color: Color32::GRAY,
+            text_color: Color32::WHITE,
+        }
+    }
+}

src/widget.rs

@@ -0,0 +1,211 @@
+use egui::{Color32, Response, Sense, Ui, Widget};
+
+use crate::config::KnobConfig;
+use crate::render::KnobRenderer;
+use crate::style::{KnobStyle, LabelPosition};
+
+pub struct Knob<'a> {
+    pub(crate) value: &'a mut f32,
+    pub(crate) min: f32,
+    pub(crate) max: f32,
+    pub(crate) config: KnobConfig,
+}
+
+impl<'a> Knob<'a> {
+    /// Creates a new knob widget
+    ///
+    /// # Arguments
+    /// * `value` - Mutable reference to the value controlled by the knob
+    /// * `min` - Minimum value
+    /// * `max` - Maximum value
+    /// * `style` - Visual style of the knob indicator
+    pub fn new(value: &'a mut f32, min: f32, max: f32, style: KnobStyle) -> Self {
+        Self {
+            value,
+            min,
+            max,
+            config: KnobConfig::new(style),
+        }
+    }
+
+    /// Sets the angular sweep range of the knob
+    ///
+    /// This controls where the knob starts and how far it can rotate. By default,
+    /// knobs start at the left (180°) and sweep 270° clockwise to bottom.
+    ///
+    /// # Arguments
+    /// * `start_angle_normalized` - Starting position as fraction of full circle:
+    ///   - `0.0` = bottom (6 o'clock)
+    ///   - `0.25` = left (9 o'clock)
+    ///   - `0.5` = top (12 o'clock)
+    ///   - `0.75` = right (3 o'clock)
+    /// * `range` - How far the knob can sweep as fraction of full circle:
+    ///   - `0.25` = quarter turn (90°)
+    ///   - `0.5` = half turn (180°)
+    ///   - `0.75` = three-quarter turn (270°)
+    ///   - `1.0` = full turn (360°)
+    ///   - Values > 1.0 create multi-turn knobs
+    ///   - Negative values are clamped to 0.0
+    ///
+    /// Note: the start angle is offset by PI/2 so that `0.0` is at the bottom (6 o'clock)
+    pub fn with_sweep_range(mut self, start_angle_normalized: f32, range: f32) -> Self {
+        if start_angle_normalized.is_nan() || range.is_nan() {
+            return self;
+        }
+
+        self.config.min_angle =
+            start_angle_normalized.rem_euclid(1.0) * std::f32::consts::TAU + std::f32::consts::PI / 2.0;
+        self.config.max_angle = self.config.min_angle + range.max(0.0) * std::f32::consts::TAU;
+        self
+    }
+
+    /// Sets the size of the knob
+    pub fn with_size(mut self, size: f32) -> Self {
+        self.config.size = size;
+        self
+    }
+
+    /// Sets the font size for the label
+    pub fn with_font_size(mut self, size: f32) -> Self {
+        self.config.font_size = size;
+        self
+    }
+
+    /// Sets the stroke width for the knob's outline and indicator
+    pub fn with_stroke_width(mut self, width: f32) -> Self {
+        self.config.stroke_width = width;
+        self
+    }
+
+    /// Sets the colors for different parts of the knob
+    ///
+    /// # Arguments
+    /// * `knob_color` - Color of the knob's outline
+    /// * `line_color` - Color of the indicator
+    /// * `text_color` - Color of the label text
+    pub fn with_colors(
+        mut self,
+        knob_color: Color32,
+        line_color: Color32,
+        text_color: Color32,
+    ) -> Self {
+        self.config.colors.knob_color = knob_color;
+        self.config.colors.line_color = line_color;
+        self.config.colors.text_color = text_color;
+        self
+    }
+
+    /// Adds a label to the knob
+    ///
+    /// # Arguments
+    /// * `label` - Text to display
+    /// * `position` - Position of the label relative to the knob
+    pub fn with_label(mut self, label: impl Into<String>, position: LabelPosition) -> Self {
+        self.config.label = Some(label.into());
+        self.config.label_position = position;
+        self
+    }
+
+    /// Sets the spacing between the knob and its label
+    pub fn with_label_offset(mut self, offset: f32) -> Self {
+        self.config.label_offset = offset;
+        self
+    }
+
+    /// Sets a custom format function for displaying the value
+    ///
+    /// # Example
+    /// ```no_run
+    /// use egui_knob::{Knob, KnobStyle};
+    /// ui.add(
+    ///     Knob::new(&mut value, 0.0, 1.0, KnobStyle::Wiper)
+    ///         .with_label_format(|v| format!("{:.1}%", v * 100.0))
+    /// );
+    /// ```
+    pub fn with_label_format(mut self, format: impl Fn(f32) -> String + 'static) -> Self {
+        self.config.label_format = Box::new(format);
+        self
+    }
+
+    /// Sets the step size for value changes
+    pub fn with_step(mut self, step: Option<f32>) -> Self {
+        self.config.step = step;
+        self
+    }
+
+    /// Controls whether to show the background arc indicating the full range
+    pub fn with_background_arc(mut self, enabled: bool) -> Self {
+        self.config.show_background_arc = enabled;
+        self
+    }
+
+    /// Controls whether to show the filled segment on the background arc
+    ///
+    /// When enabled (and background arc is visible), displays a colored segment
+    /// from the minimum position to the current value position.
+    pub fn with_show_filled_segments(mut self, enabled: bool) -> Self {
+        self.config.show_filled_segments = enabled;
+        self
+    }
+
+    /// Sets the drag sensitivity for mouse interactions
+    ///
+    /// Default is 0.005.
+    pub fn with_drag_sensitivity(mut self, sensitivity: f32) -> Self {
+        self.config.drag_sensitivity = sensitivity;
+        self
+    }
+
+}
+
+impl Widget for Knob<'_> {
+    fn ui(self, ui: &mut Ui) -> Response {
+        if self.value.is_nan() {
+            *self.value = self.min;
+        }
+
+        let current_value = *self.value;
+        let renderer = KnobRenderer::new(&self.config, current_value, self.min, self.max);
+        let adjusted_size = renderer.calculate_size(ui);
+
+        let (rect, response) = ui.allocate_exact_size(adjusted_size, Sense::drag());
+
+        let mut response = response;
+        if response.dragged() {
+            let delta = response.drag_delta().y;
+            let range = self.max - self.min;
+            let step = self.config.step.unwrap_or(range * self.config.drag_sensitivity);
+            let new_value = (*self.value - delta * step).clamp(self.min, self.max);
+
+            *self.value = if let Some(step) = self.config.step {
+                let steps = ((new_value - self.min) / step).round();
+                (self.min + steps * step).clamp(self.min, self.max)
+            } else {
+                new_value
+            };
+
+            if self.value.is_nan() {
+                *self.value = self.min;
+            }
+
+            response.mark_changed();
+        }
+
+        let knob_rect = renderer.calculate_knob_rect(rect);
+        let center = knob_rect.center();
+        let radius = self.config.size / 2.0;
+
+        let updated_value = *self.value;
+        let updated_renderer = KnobRenderer::new(&self.config, updated_value, self.min, self.max);
+        updated_renderer.render_knob(ui.painter(), center, radius, response.hovered());
+        updated_renderer.render_label(ui, rect);
+
+        if self.config.label.is_some() && response.hovered() {
+            response
+                .clone()
+                .on_hover_text((self.config.label_format)(*self.value));
+        }
+
+        response
+    }
+}