1 files changed, 123 insertions, 0 deletions
diff --git a/graphics/src/widget/slider.rs b/graphics/src/widget/slider.rs
new file mode 100644
index 00000000..aeceec3f
--- /dev/null
+++ b/graphics/src/widget/slider.rs
@@ -0,0 +1,123 @@
+//! Display an interactive selector of a single value from a range of values.
+//!
+//! A [`Slider`] has some local [`State`].
+use crate::{Backend, Primitive, Renderer};
+use iced_native::mouse;
+use iced_native::slider;
+use iced_native::{Background, Color, Point, Rectangle};
+
+pub use iced_native::slider::State;
+pub use iced_style::slider::{Handle, HandleShape, Style, StyleSheet};
+
+/// An horizontal bar and a handle that selects a single value from a range of
+/// values.
+///
+/// This is an alias of an `iced_native` slider with an `iced_wgpu::Renderer`.
+pub type Slider<'a, T, Message, Backend> =
+    iced_native::Slider<'a, T, Message, Renderer<Backend>>;
+
+impl<B> slider::Renderer for Renderer<B>
+where
+    B: Backend,
+{
+    type Style = Box<dyn StyleSheet>;
+
+    const DEFAULT_HEIGHT: u16 = 22;
+
+    fn draw(
+        &mut self,
+        bounds: Rectangle,
+        cursor_position: Point,
+        range: std::ops::RangeInclusive<f32>,
+        value: f32,
+        is_dragging: bool,
+        style_sheet: &Self::Style,
+    ) -> Self::Output {
+        let is_mouse_over = bounds.contains(cursor_position);
+
+        let style = if is_dragging {
+            style_sheet.dragging()
+        } else if is_mouse_over {
+            style_sheet.hovered()
+        } else {
+            style_sheet.active()
+        };
+
+        let rail_y = bounds.y + (bounds.height / 2.0).round();
+
+        let (rail_top, rail_bottom) = (
+            Primitive::Quad {
+                bounds: Rectangle {
+                    x: bounds.x,
+                    y: rail_y,
+                    width: bounds.width,
+                    height: 2.0,
+                },
+                background: Background::Color(style.rail_colors.0),
+                border_radius: 0.0,
+                border_width: 0.0,
+                border_color: Color::TRANSPARENT,
+            },
+            Primitive::Quad {
+                bounds: Rectangle {
+                    x: bounds.x,
+                    y: rail_y + 2.0,
+                    width: bounds.width,
+                    height: 2.0,
+                },
+                background: Background::Color(style.rail_colors.1),
+                border_radius: 0.0,
+                border_width: 0.0,
+                border_color: Color::TRANSPARENT,
+            },
+        );
+
+        let (handle_width, handle_height, handle_border_radius) = match style
+            .handle
+            .shape
+        {
+            HandleShape::Circle { radius } => {
+                (radius * 2.0, radius * 2.0, radius)
+            }
+            HandleShape::Rectangle {
+                width,
+                border_radius,
+            } => (f32::from(width), f32::from(bounds.height), border_radius),
+        };
+
+        let (range_start, range_end) = range.into_inner();
+
+        let handle_offset = if range_start >= range_end {
+            0.0
+        } else {
+            (bounds.width - handle_width) * (value - range_start)
+                / (range_end - range_start)
+        };
+
+        let handle = Primitive::Quad {
+            bounds: Rectangle {
+                x: bounds.x + handle_offset.round(),
+                y: rail_y - handle_height / 2.0,
+                width: handle_width,
+                height: handle_height,
+            },
+            background: Background::Color(style.handle.color),
+            border_radius: handle_border_radius,
+            border_width: style.handle.border_width,
+            border_color: style.handle.border_color,
+        };
+
+        (
+            Primitive::Group {
+                primitives: vec![rail_top, rail_bottom, handle],
+            },
+            if is_dragging {
+                mouse::Interaction::Grabbing
+            } else if is_mouse_over {
+                mouse::Interaction::Grab
+            } else {
+                mouse::Interaction::default()
+            },
+        )
+    }
+}