Minor ergonomics refactor

ui.odin

@@ -15,7 +15,7 @@ rect2 :: struct {x, y, width, height: f32}
 @private ctx: ^Context
 
 Context :: struct {
-	container_position, element_position: v2,
+	element_position: v2,
 	container_stack: [dynamic]^Element,
 	elements: [dynamic]Element,
 	same_line: bool,
@@ -28,15 +28,19 @@ init :: proc(state: ^Context, element_capacity: int, allocator := context.alloca
 
 Element :: struct {
 	area: rect2,
+	using config: ElementConfiguration,
+	type: ElementType,
+}
+
+ElementConfiguration :: struct {
 	label: cstring,
 	color: [4]u8,
-	data: ElementData,
 	margin, padding: v2,
 }
 
-ElementData :: union {
-	ElementData_Container,
-	ElementData_Button,
+ElementType :: enum {
+	Container,
+	Button,
 }
 
 Size_Pixels :: distinct f32
@@ -57,7 +61,6 @@ Axis :: enum {X, Y}
 
 start :: proc(ui_context: ^Context, position: v2) {
 	ctx = ui_context
-	ctx.container_position = position
 	ctx.element_position = position
 	clear(&ctx.container_stack)
 	clear(&ctx.elements)
@@ -81,18 +84,12 @@ element_get_inner_area :: proc(element: Element) -> rect2 {
 	return rect_grow(element.area, -element.padding * 2.0)
 }
 
-ElementData_Container :: struct {
-	margin, padding: v2,
-}
-
-container_begin :: proc(dimensions: Dimensions, margin: v2, padding: v2, label: cstring, color: [4]u8) {
-	ctx.container_position += margin
-	size := _resolve_dimensions(dimensions) - margin * 2.0
-	area := rect2{**ctx.container_position, **size}
-	ctx.container_position += padding
-	ctx.element_position = ctx.container_position
-	data := ElementData_Container {margin = margin, padding = padding}
-	element := Element{area = area, color = color, label = label, data = data, margin = margin, padding = padding}
+container_begin :: proc(dimensions: Dimensions, config: ElementConfiguration) {
+	ctx.element_position += config.margin
+	size := _resolve_dimensions(dimensions) - config.margin * 2.0
+	area := rect2{**ctx.element_position, **size}
+	ctx.element_position += config.padding
+	element := Element{area = area, config = config, type = .Container}
 	append(&ctx.elements, element)
 	container := _element_last()
 	append(&ctx.container_stack, container)
@@ -101,12 +98,8 @@ container_begin :: proc(dimensions: Dimensions, margin: v2, padding: v2, label:
 container_end :: proc() {
 	container := pop(&ctx.container_stack)
 	// TODO: Set flex
-	data := container.data.(ElementData_Container)
-	ctx.container_position = rect_get_bl(container.area) + data.margin.y
-	ctx.element_position = ctx.container_position
-}
-
-ElementData_Button :: struct {
+	outer := element_get_outer_area(container^)
+	ctx.element_position = rect_get_bl(outer)
 }
 
 button :: proc(dimensions: Dimensions) {