updated cargo.lock

Support for using mouse scroll wheel to change values

.github/workflows/publish.yml

@@ -0,0 +1,27 @@
+name: Publish to crates.io
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+      
+      - name: Check if version matches tag
+        run: |
+          TAG=${GITHUB_REF#refs/tags/v}
+          CARGO_VERSION=$(grep '^version' Cargo.toml | head -1 | cut -d'"' -f2)
+          if [ "$TAG" != "$CARGO_VERSION" ]; then
+            echo "Tag version ($TAG) doesn't match Cargo.toml version ($CARGO_VERSION)"
+            exit 1
+          fi
+      
+      - name: Publish to crates.io
+        run: cargo publish --token ${{ secrets.CARGO_REGISTRY_TOKEN }}

.gitignore

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

.vscode/launch.json

@@ -0,0 +1,26 @@
+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "type": "lldb",
+            "request": "launch",
+            "name": "Debug example 'example_knob'",
+            "cargo": {
+                "args": [
+                    "build",
+                    "--example=example_knob",
+                    "--package=egui_knob"
+                ],
+                "filter": {
+                    "name": "example_knob",
+                    "kind": "example"
+                }
+            },
+            "args": [],
+            "cwd": "${workspaceFolder}"
+        },
+    ]
+}

CHANGELOG.md

@@ -0,0 +1,97 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+## [0.3.9] - 2026-01-13
+
+### 🚀 Features
+
+- added support for using mouse scroll wheel to change values ([#PR7](https://github.com/obsqrbtz/egui_knob/pull/7) by [maor1993](https://github.com/maor1993))
+
+## [0.3.8] - 2026-01-12
+
+### 🚀 Features
+
+- added `with_double_click_reset` option ([#PR6](https://github.com/obsqrbtz/egui_knob/pull/6) by [maor1993](https://github.com/maor1993))
+
+## [0.3.7] - 2026-01-06
+
+### 🛠 Maintenance
+
+- expose egui types
+
+## [0.3.6] - 2025-07-15
+
+### 🛠 Maintenance
+
+- cleaned up io a bit
+
+## [0.3.5] - 2025-07-15
+
+### 🛠 Maintenance
+
+- Restructured the project
+
+### 📚 Documentation
+
+- Updated readme, added contributing guidelines
+
+## [0.3.4] - 2025-07-15
+
+### 🛠 Maintenance
+
+- Bump egui version to 0.33
+
+### 📚 Documentation
+
+- Updated usage example in readme
+
+
+## [0.3.1] - 2025-07-15
+
+### 🚀 Features
+
+- Added background arc
+
+### 🐛 Bug Fixes
+
+- Sanitize NaNs
+
+## [0.3.1] - 2025-07-15
+
+### 🛠 Maintenance
+
+- Bump egui version to 0.32
+
+## [0.3.0] - 2025-07-07
+
+### 🚀 Features
+
+- Add configurable sweep range with `with_sweep_range()` method ([PR#2](https://github.com/obsqrbtz/egui_knob/pull/2) by [sacha-renault](https://github.com/sacha-renault))
+
+## [0.2.0] - 2025-05-12
+
+- Bump egui and eframe versions ([PR#1](https://github.com/obsqrbtz/egui_knob/pull/1) by [chloebrett](https://github.com/chloebrett))
+
+## [0.1.9] - 2025-02-04
+
+### 🚀 Features
+
+- Exposed label format
+- Add step size configuration
+
+### 🐛 Bug Fixes
+
+- Add label offsets and position in relative to the widget rect
+
+### 📚 Documentation
+
+- Added doc comments
+
+## [0.1.8] - 2025-02-03
+
+### 🐛 Bug Fixes
+
+- Mark response changed when knob was dragged
+
+<!-- generated by git-cliff -->

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.toml

@@ -1,10 +1,12 @@
 [package]
 name = "egui_knob"
-version = "0.1.4"
-edition = "2021"
+version = "0.3.9"
+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"]
@@ -19,7 +21,7 @@ name = "example_knob"
 path = "examples/example_knob.rs"
 
 [dependencies]
-egui = "0.30"
+egui = "0.33"
 
 [dev-dependencies]
-eframe = { version = "0.30.0", features = ["default_fonts"] }
+eframe = { version = "0.33", features = ["default_fonts"] }

README.md

@@ -1,17 +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.
-- Customizable colors for the knob and line.
-- Label positions (Top, Bottom, Left, Right).
-- Two styles: Wiper and Dot.
+- Adjustable size, font size, and stroke width
+- Customizable colors for the knob, indicator, and text
+- Label positions (Top, Bottom, Left, Right)
+- Custom label formatting
+- Two visual styles: Wiper and Dot
+- Configurable sweep range
+- Background arc with filled segments
+- Adjustable drag sensitivity
 
 ## Installation
 
@@ -19,27 +25,93 @@ To use the Knob widget in your project, add the following to your `Cargo.toml`:
 
 ```toml
 [dependencies]
-egui = "0.30"
-egui_knob = "*"
+egui = "0.33"
+eframe = "0.33"
+egui_knob = "0.3.9"
 ```
 
-## Usage example
+## Usage
+
+### Basic Example
 
 ```rust
-use egui::{Color32, Context};
-use egui_knob::Knob;
+use egui_knob::{Knob, KnobStyle, LabelPosition};
+use eframe::egui;
 
-// ..
+struct KnobApp {
+    value: f32,
+}
 
-let mut value: f32 = 0.5;
-let knob = Knob::new(&mut value, 0.0, 1.0, KnobStyle::Wiper)
-    .with_size(50.0)
-    .with_font_size(14.0)
-    .with_stroke_width(3.0)
-    .with_colors(Color32::GRAY, Color32::WHITE, Color32::WHITE)
-    .with_label("Volume", LabelPosition::Top);
+impl Default for KnobApp {
+    fn default() -> Self {
+        Self { value: 0.5 }
+    }
+}
 
-egui::CentralPanel::default().show(ctx, |ui| {
-    ui.add(knob);
-});
+impl eframe::App for KnobApp {
+    fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
+        egui::CentralPanel::default().show(ctx, |ui| {
+            let knob = Knob::new(&mut self.value, 0.0, 1.0, KnobStyle::Wiper)
+                .with_size(50.0)
+                .with_font_size(14.0)
+                .with_colors(egui::Color32::GRAY, egui::Color32::WHITE, egui::Color32::WHITE)
+                .with_stroke_width(3.0)
+                .with_label("Volume", LabelPosition::Top);
+
+            ui.add(knob);
+        });
+    }
+}
+
+fn main() -> eframe::Result<()> {
+    eframe::run_native(
+        "Knob Example",
+        eframe::NativeOptions::default(),
+        Box::new(|_cc| Ok(Box::new(KnobApp::default()))),
+    )
+}
 ```
+
+### 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

@@ -1,61 +1,123 @@
 use eframe::egui;
-use egui_knob::Knob;
+use egui_knob::{Knob, KnobStyle, LabelPosition};
 
 fn main() -> eframe::Result<()> {
+    let options = eframe::NativeOptions {
+        viewport: egui::ViewportBuilder::default()
+            .with_inner_size([600.0, 350.0])
+            .with_title("Knob demo"),
+        ..Default::default()
+    };
+
     eframe::run_native(
-        "Knob Example",
-        eframe::NativeOptions::default(),
-        Box::new(|_cc| Ok(Box::new(KnobExample::default()))),
+        "Knob demo",
+        options,
+        Box::new(|_cc| Ok(Box::new(KnobDemo::default()))),
     )
 }
 
-struct KnobExample {
-    value: f32,
+struct KnobDemo {
+    values: [f32; 6],
+    show_bg_arc: bool,
+    show_filled: bool,
+    use_step: bool,
+    knob_color: egui::Color32,
+    line_color: egui::Color32,
+    text_color: egui::Color32,
 }
 
-impl Default for KnobExample {
+impl Default for KnobDemo {
     fn default() -> Self {
-        Self { value: 0.0 }
+        Self {
+            values: [f32::NAN; 6],
+            show_bg_arc: true,
+            show_filled: true,
+            use_step: false,
+            knob_color: egui::Color32::DARK_GRAY,
+            line_color: egui::Color32::LIGHT_BLUE,
+            text_color: egui::Color32::WHITE,
+        }
     }
 }
 
-impl eframe::App for KnobExample {
+impl eframe::App for KnobDemo {
     fn update(&mut self, ctx: &egui::Context, _frame: &mut eframe::Frame) {
         egui::CentralPanel::default().show(ctx, |ui| {
+            ui.heading("Knob demo");
+            ui.separator();
+
             ui.horizontal(|ui| {
-                ui.add(
-                    Knob::new(&mut self.value, 0.0, 100.0, egui_knob::KnobStyle::Dot)
-                        .with_label("Gain", egui_knob::LabelPosition::Bottom)
-                        .with_size(50.0),
-                );
-                ui.add(
-                    Knob::new(&mut self.value, 0.0, 100.0, egui_knob::KnobStyle::Wiper)
-                        .with_label("Gain", egui_knob::LabelPosition::Bottom)
-                        .with_size(50.0),
-                );
-                ui.add_space(15.0);
-                ui.add(
-                    Knob::new(&mut self.value, 0.0, 100.0, egui_knob::KnobStyle::Dot)
-                        .with_label("Gain", egui_knob::LabelPosition::Bottom)
-                        .with_colors(
-                            egui::Color32::DARK_GRAY,
-                            egui::Color32::WHITE,
-                            egui::Color32::WHITE,
-                        )
-                        .with_size(50.0),
-                );
-                ui.add_space(15.0);
-                ui.add(
-                    Knob::new(&mut self.value, 0.0, 100.0, egui_knob::KnobStyle::Wiper)
-                        .with_label("Gain", egui_knob::LabelPosition::Bottom)
-                        .with_colors(
-                            egui::Color32::DARK_GRAY,
-                            egui::Color32::WHITE,
-                            egui::Color32::LIGHT_BLUE,
-                        )
-                        .with_size(50.0),
-                );
+                ui.label("Global Settings:");
+                ui.checkbox(&mut self.show_bg_arc, "Background arc");
+                ui.checkbox(&mut self.show_filled, "Filled segment");
+                ui.checkbox(&mut self.use_step, "Step (0.02)");
             });
+
+            ui.horizontal(|ui| {
+                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.add_space(10.0);
+            egui::Grid::new("knob_grid")
+                .num_columns(3)
+                .spacing([30.0, 20.0])
+                .show(ui, |ui| {
+                    for (i, (label, config)) in [
+                        ("Basic Dot", KnobStyle::Dot),
+                        ("Wiper, Sweep", KnobStyle::Wiper),
+                        ("Thick Stroke", KnobStyle::Wiper),
+                        ("360° Sweep", KnobStyle::Wiper),
+                        ("Multi-Turn", KnobStyle::Dot),
+                        ("Large Font", KnobStyle::Wiper),
+                    ]
+                    .iter()
+                    .enumerate()
+                    {
+                        ui.vertical(|ui| {
+                            let mut knob = Knob::new(&mut self.values[i], 0.0, 1.0, *config)
+                                .with_label(*label, LabelPosition::Bottom)
+                                .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(0.02))
+                                .with_double_click_reset(0.5)
+                                .with_middle_scroll();
+
+                            if *label == "Wiper, Sweep" {
+                                knob = knob.with_sweep_range(0.25, 0.75).with_size(50.0);
+                            }
+                            if *label == "Thick Stroke" {
+                                knob = knob.with_stroke_width(4.0).with_size(60.0);
+                            }
+                            if *label == "360° Sweep" {
+                                knob = knob.with_sweep_range(0.5, 1.0);
+                            }
+                            if *label == "Multi-Turn" {
+                                knob = knob.with_sweep_range(0.0, 2.5);
+                            }
+                            if *label == "Large Font" {
+                                knob = knob.with_size(70.0).with_font_size(18.0);
+                            }
+
+                            ui.add(knob);
+                        });
+
+                        if (i + 1) % 3 == 0 {
+                            ui.end_row();
+                        }
+                    }
+                });
+
+            ui.add_space(10.0);
+            ui.separator();
         });
     }
 }

src/config.rs

@@ -0,0 +1,45 @@
+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,
+    pub(crate) reset_value: Option<f32>,
+    pub(crate) allow_scroll: bool,
+}
+
+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,
+            reset_value: None,
+            allow_scroll:false
+        }
+    }
+}

src/lib.rs

@@ -1,188 +1,9 @@
-use egui::{Align2, Color32, Response, Sense, Stroke, Ui, Vec2, Widget};
+mod config;
+mod render;
+mod style;
+mod widget;
 
-pub enum LabelPosition {
-    Top,
-    Bottom,
-    Left,
-    Right,
-}
+pub use egui;
 
-pub enum KnobStyle {
-    Wiper,
-    Dot,
-}
-
-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,
-}
-
-impl<'a> Knob<'a> {
-    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,
-        }
-    }
-
-    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,
-        text_color: Color32,
-    ) -> Self {
-        self.knob_color = knob_color;
-        self.line_color = line_color;
-        self.text_color = text_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 knob_size = Vec2::splat(self.size);
-
-        let label_size = if let Some(label) = &self.label {
-            let font_id = egui::FontId::proportional(self.font_size);
-            ui.painter()
-                .layout(
-                    format!("{}: {:.2}", label, self.value),
-                    font_id,
-                    Color32::WHITE,
-                    f32::INFINITY,
-                )
-                .size()
-        } else {
-            Vec2::ZERO
-        };
-
-        let label_padding = 12.0;
-
-        let adjusted_size = match self.label_position {
-            LabelPosition::Top | LabelPosition::Bottom => {
-                Vec2::new(knob_size.x, knob_size.y + label_size.y + label_padding)
-            }
-            LabelPosition::Left | LabelPosition::Right => {
-                Vec2::new(knob_size.x + label_size.x + label_padding, knob_size.y)
-            }
-        };
-
-        let (rect, 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 = range * 0.005;
-            *self.value = (*self.value - delta * step).clamp(self.min, self.max);
-        }
-
-        let painter = ui.painter();
-        let center = rect.center();
-        let radius = knob_size.x / 2.0;
-        let angle = (*self.value - self.min) / (self.max - self.min) * std::f32::consts::PI * 1.5
-            - std::f32::consts::PI;
-
-        painter.circle_stroke(
-            center,
-            radius,
-            Stroke::new(self.stroke_width, self.knob_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}: {:.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 = label_padding;
-            let label_pos = match self.label_position {
-                LabelPosition::Top => {
-                    rect.center()
-                        + Vec2::new(-text_size.x / 2.0, -radius - label_offset - text_size.y)
-                }
-                LabelPosition::Bottom => {
-                    rect.center() + Vec2::new(-text_size.x / 2.0, radius + label_offset)
-                }
-                LabelPosition::Left => {
-                    rect.center()
-                        + Vec2::new(-radius - label_offset - text_size.x, -text_size.y / 2.0)
-                }
-                LabelPosition::Right => {
-                    rect.center() + Vec2::new(radius + label_offset, -text_size.y / 2.0)
-                }
-            };
-
-            ui.painter().text(
-                label_pos,
-                Align2::LEFT_TOP,
-                label_text,
-                font_id,
-                self.text_color,
-            );
-        }
-
-        response
-    }
-}
+pub use style::{KnobStyle, LabelPosition};
+pub use widget::Knob;

src/render.rs

@@ -0,0 +1,205 @@
+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(1.15)
+        } else {
+            self.config.colors.knob_color
+        };
+
+        // TODO: make an option
+        painter.circle_filled(
+            center,
+            radius - self.config.stroke_width / 2.0,
+            self.config.colors.knob_color.gamma_multiply(0.15),
+        );
+
+        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 * 0.65);
+                painter.line_segment(
+                    [center, pointer],
+                    Stroke::new(
+                        self.config.stroke_width * 1.2,
+                        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 * 1.8,
+                    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 = 128;
+        let arc_color = self.config.colors.knob_color.gamma_multiply(0.35);
+        let arc_radius = radius * 0.85;
+
+        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;
+
+            if filled_segments > 0 {
+                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 * 1.2,
+                        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 = 4.0;
+
+            let (label_pos, alignment) = match self.config.label_position {
+                LabelPosition::Top => (
+                    Vec2::new(rect.center().x, rect.min.y + label_padding),
+                    Align2::CENTER_TOP,
+                ),
+                LabelPosition::Bottom => (
+                    Vec2::new(rect.center().x, rect.max.y - label_padding),
+                    Align2::CENTER_BOTTOM,
+                ),
+                LabelPosition::Left => (
+                    Vec2::new(rect.min.x + label_padding, rect.center().y),
+                    Align2::LEFT_CENTER,
+                ),
+                LabelPosition::Right => (
+                    Vec2::new(rect.max.x - label_padding, 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 + self.config.stroke_width * 2.0);
+
+        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 = 8.0;
+
+        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 + self.config.label_offset,
+            ),
+            LabelPosition::Left | LabelPosition::Right => Vec2::new(
+                knob_size.x + label_size.x + label_padding + self.config.label_offset,
+                knob_size.y.max(label_size.y + label_padding),
+            ),
+        }
+    }
+
+    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 +1,238 @@
+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
+    }
+
+    /// Sets a reset value to return to on doubleclick event.
+    pub fn with_double_click_reset(mut self, reset_value: f32) -> Self {
+        self.config.reset_value = Some(reset_value);
+        self
+    }
+
+    /// Allows user to use scroll wheel to change knob value
+    /// Uses config.step for the increment value
+    pub fn with_middle_scroll(mut self) -> Self {
+        self.config.allow_scroll = true;
+        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::click_and_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();
+        } else if response.double_clicked() {
+            if let Some(reset_value) = self.config.reset_value {
+                *self.value = reset_value
+            }
+        } else if response.hovered() & self.config.allow_scroll {
+            if let Some(scoll) = ui.input(|input| {
+                input.events.iter().find_map(|e| match e {
+                    egui::Event::MouseWheel { delta, .. } => Some(*delta),
+                    _ => None,
+                })
+            }) {
+                *self.value = (*self.value
+                    + scoll.y * self.config.step.unwrap_or(self.config.drag_sensitivity))
+                .clamp(self.min, self.max);
+            }
+        }
+
+        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
+    }
+}