Support viewport-relative widget sizing

src/widget/image/tests.rs

@@ -32,14 +32,14 @@ fn cover_builder_sets_cover_flag()
 fn size_builder_sets_explicit_display_size()
 {
 	let img = Image::new( solid_rgba( 4, 4 ), 4, 4 ).size( 120.0, 80.0 );
-	assert_eq!( img.display_size, Some( ( 120.0, 80.0 ) ) );
+	assert_eq!( img.display_size, Some( ( Length::px( 120.0 ), Length::px( 80.0 ) ) ) );
 }
 
 #[ test ]
-fn size_builder_clamps_negative_dimensions_to_zero()
+fn size_builder_keeps_length_values_for_later_viewport_resolution()
 {
 	let img = Image::new( solid_rgba( 4, 4 ), 4, 4 ).size( -10.0, -20.0 );
-	assert_eq!( img.display_size, Some( ( 0.0, 0.0 ) ) );
+	assert_eq!( img.display_size, Some( ( Length::px( -10.0 ), Length::px( -20.0 ) ) ) );
 }
 
 #[ test ]
@@ -57,7 +57,8 @@ fn preferred_size_default_scales_height_to_match_width_aspect()
 {
 	// 200×100 source image at max_width = 400 → scale = 2 → height 200.
 	let img = Image::new( solid_rgba( 200, 100 ), 200, 100 );
-	let ( w, h ) = img.preferred_size( 400.0 );
+	let canvas = Canvas::new( 480, 900 );
+	let ( w, h ) = img.preferred_size( 400.0, &canvas );
 	assert_eq!( w, 400.0 );
 	assert_eq!( h, 200.0 );
 }
@@ -66,7 +67,16 @@ fn preferred_size_default_scales_height_to_match_width_aspect()
 fn preferred_size_with_explicit_size_wins_over_aspect_logic()
 {
 	let img = Image::new( solid_rgba( 200, 100 ), 200, 100 ).size( 50.0, 25.0 );
-	assert_eq!( img.preferred_size( 1000.0 ), ( 50.0, 25.0 ) );
+	let canvas = Canvas::new( 480, 900 );
+	assert_eq!( img.preferred_size( 1000.0, &canvas ), ( 50.0, 25.0 ) );
+}
+
+#[ test ]
+fn preferred_size_resolves_explicit_viewport_lengths()
+{
+	let img = Image::new( solid_rgba( 200, 100 ), 200, 100 ).size( Length::vw( 10.0 ), Length::vh( 10.0 ) );
+	let canvas = Canvas::new( 480, 900 );
+	assert_eq!( img.preferred_size( 1000.0, &canvas ), ( 48.0, 90.0 ) );
 }
 
 #[ test ]
@@ -74,7 +84,8 @@ fn preferred_size_cover_mode_keeps_aspect_ratio()
 {
 	// 100×50 source in cover mode at max_width = 300 → height = 300 * (50/100) = 150.
 	let img = Image::new( solid_rgba( 100, 50 ), 100, 50 ).cover();
-	let ( w, h ) = img.preferred_size( 300.0 );
+	let canvas = Canvas::new( 480, 900 );
+	let ( w, h ) = img.preferred_size( 300.0, &canvas );
 	assert_eq!( w, 300.0 );
 	assert_eq!( h, 150.0 );
 }
@@ -87,7 +98,8 @@ fn preferred_size_cover_and_default_match_for_uniform_scaling()
 	// when the source is taller than wide.
 	let normal  = Image::new( solid_rgba( 100, 50 ), 100, 50 );
 	let covered = Image::new( solid_rgba( 100, 50 ), 100, 50 ).cover();
-	assert_eq!( normal.preferred_size( 200.0 ), covered.preferred_size( 200.0 ) );
+	let canvas = Canvas::new( 480, 900 );
+	assert_eq!( normal.preferred_size( 200.0, &canvas ), covered.preferred_size( 200.0, &canvas ) );
 }
 
 // ── Arc sharing ───────────────────────────────────────────────────────────