chore: restructured the project

docs: added contributing guidelines and updated rreadme

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,
+        }
+    }
+}