Support viewport-relative widget sizing

src/widget/vslider/mod.rs

@@ -2,7 +2,7 @@
 // Copyright (C) 2026 Liberux Labs, S. L. <info@liberux.net>
 
 use std::sync::Arc;
-use crate::types::Rect;
+use crate::types::{ Length, Rect };
 use crate::render::Canvas;
 use super::Element;
 use super::slider::intersect_clip;
@@ -65,10 +65,10 @@ pub struct VSlider<Msg: Clone>
 	/// Current value in `[0.0, 1.0]`. `0.0` paints no fill; `1.0` fills the
 	/// whole pill.
 	pub value:     f32,
-	/// Fixed width of the pill in pixels. Defaults to 56.
-	pub width:     f32,
-	/// Fixed height of the pill in pixels. Defaults to 160.
-	pub height:    f32,
+	/// Fixed width of the pill in logical units. Defaults to 56 px.
+	pub width:     Length,
+	/// Fixed height of the pill in logical units. Defaults to 160 px.
+	pub height:    Length,
 	/// Callback invoked with the new value when the slider is tapped or
 	/// dragged. `Arc` (not `Box`) so the layout pass can clone it into the
 	/// per-leaf handler snapshot for O(1) dispatch on input events.
@@ -93,8 +93,8 @@ impl<Msg: Clone> VSlider<Msg>
 		Self
 		{
 			value:         value.clamp( 0.0, 1.0 ),
-			width:         theme::WIDTH,
-			height:        theme::HEIGHT,
+			width:         Length::px( theme::WIDTH ),
+			height:        Length::px( theme::HEIGHT ),
 			on_change:     None,
 			track_surface: theme::SURFACE_TRACK,
 			fill_surface:  theme::SURFACE_FILL,
@@ -117,12 +117,13 @@ impl<Msg: Clone> VSlider<Msg>
 		self
 	}
 
-	/// Override the fixed pill `(width, height)` in pixels. Both are clamped
-	/// to a minimum of `2.0` so a rounded pill can always be drawn.
-	pub fn size( mut self, width: f32, height: f32 ) -> Self
+	/// Override the fixed pill `(width, height)` in logical units. Both are
+	/// clamped to a minimum of `2.0` after viewport-relative values resolve,
+	/// so a rounded pill can always be drawn.
+	pub fn size( mut self, width: impl Into<Length>, height: impl Into<Length> ) -> Self
 	{
-		self.width  = width.max( 2.0 );
-		self.height = height.max( 2.0 );
+		self.width  = width.into();
+		self.height = height.into();
 		self
 	}
 
@@ -135,9 +136,13 @@ impl<Msg: Clone> VSlider<Msg>
 
 	/// Return the preferred `(width, height)`. `max_width` is ignored — see
 	/// the type-level docs on intrinsic sizing.
-	pub fn preferred_size( &self, _max_width: f32, _canvas: &Canvas ) -> (f32, f32)
+	pub fn preferred_size( &self, _max_width: f32, canvas: &Canvas ) -> (f32, f32)
 	{
-		( self.width, self.height )
+		let viewport = canvas.viewport_logical();
+		(
+			self.width.resolve( viewport, Length::EM_BASE_DEFAULT ).max( 2.0 ),
+			self.height.resolve( viewport, Length::EM_BASE_DEFAULT ).max( 2.0 ),
+		)
 	}
 
 	/// Compute the value `[0.0, 1.0]` from a tap/drag y position within `rect`.

src/widget/vslider/tests.rs

@@ -100,8 +100,8 @@ fn preferred_size_ignores_max_width()
 fn default_dimensions_are_the_theme_constants()
 {
 	let s: VSlider<()> = vslider( 0.0 );
-	assert_eq!( s.width,  theme::WIDTH );
-	assert_eq!( s.height, theme::HEIGHT );
+	assert_eq!( s.width,  Length::px( theme::WIDTH ) );
+	assert_eq!( s.height, Length::px( theme::HEIGHT ) );
 }
 
 #[ test ]