First commit. Version 0.1.0

tests/slider_math.rs

@@ -0,0 +1,65 @@
+use ltk::test_support::value_from_x_in_rect;
+use ltk::Rect;
+
+fn rect( x: f32, y: f32, w: f32, h: f32 ) -> Rect
+{
+	Rect { x, y, width: w, height: h }
+}
+
+#[ test ]
+fn left_edge_clamps_to_zero()
+{
+	let r = rect( 0.0, 0.0, 200.0, 36.0 );
+	assert_eq!( value_from_x_in_rect( r, 0.0 ), 0.0 );
+	assert_eq!( value_from_x_in_rect( r, -50.0 ), 0.0 );
+}
+
+#[ test ]
+fn right_edge_clamps_to_one()
+{
+	let r = rect( 0.0, 0.0, 200.0, 36.0 );
+	assert_eq!( value_from_x_in_rect( r, 200.0 ), 1.0 );
+	assert_eq!( value_from_x_in_rect( r, 999.0 ), 1.0 );
+}
+
+#[ test ]
+fn center_returns_half()
+{
+	// The thumb adds padding on both sides, so the geometric center of the
+	// rect produces ~0.5 (within the THUMB_SIZE/2 tolerance).
+	let r = rect( 0.0, 0.0, 200.0, 36.0 );
+	let v = value_from_x_in_rect( r, 100.0 );
+	assert!( ( v - 0.5 ).abs() < 0.1, "expected ~0.5 got {}", v );
+}
+
+#[ test ]
+fn rect_offset_translates_correctly()
+{
+	let r = rect( 500.0, 0.0, 200.0, 36.0 );
+	assert_eq!( value_from_x_in_rect( r, 500.0 ), 0.0 );
+	assert_eq!( value_from_x_in_rect( r, 700.0 ), 1.0 );
+	let v = value_from_x_in_rect( r, 600.0 );
+	assert!( ( v - 0.5 ).abs() < 0.1, "expected ~0.5 got {}", v );
+}
+
+#[ test ]
+fn output_is_always_in_unit_range()
+{
+	let r = rect( 10.0, 10.0, 300.0, 36.0 );
+	for x in -100i32 ..= 500
+	{
+		let v = value_from_x_in_rect( r, x as f32 );
+		assert!( ( 0.0..= 1.0 ).contains( &v ), "v={} out of range at x={}", v, x );
+	}
+}
+
+#[ test ]
+fn very_narrow_rect_does_not_divide_by_zero()
+{
+	// Width < THUMB_SIZE — track_w is clamped to 1.0 internally so the
+	// formula stays defined.
+	let r = rect( 0.0, 0.0, 4.0, 36.0 );
+	let v = value_from_x_in_rect( r, 2.0 );
+	assert!( v.is_finite() );
+	assert!( ( 0.0..= 1.0 ).contains( &v ) );
+}