Text widget changes (squash)

Use separate bool for layout_dirty vs box just opened, as these two states are not really mutually exclusive. Fixes a bug where the box was not considered just opened since the "open" state was overwritten by the "switch" state.

Use center vertical alignment for a just opened box. This is admittedly a subjective matter. However, it looked a bit weird to me how it would scroll past the first few elements when you select, say, just the second or third element. With center, both the first few, and the last items, are shown when selecting something near the beginning or the end respectively. This also feels more symmetrical when the selection box ends up being placed above the select element.

Source/Core/Elements/WidgetDropDown.cpp

@@ -48,7 +48,8 @@ WidgetDropDown::WidgetDropDown(ElementFormControl* element)
 
 	lock_selection = false;
 	selection_dirty = false;
-	box_layout_dirty = DropDownBoxLayoutType::None;
+	box_layout_dirty = false;
+	box_opened_since_last_format = false;
 	value_rml_dirty = false;
 	value_layout_dirty = false;
 	box_visible = false;
@@ -151,7 +152,7 @@ void WidgetDropDown::OnUpdate()
 
 void WidgetDropDown::OnRender()
 {
-	if (box_visible && box_layout_dirty != DropDownBoxLayoutType::None)
+	if (box_visible && box_layout_dirty)
 	{
 		// Layout the selection box.
 		// The following procedure should ensure that the selection box is never (partly) outside of the context's window.
@@ -235,13 +236,15 @@ void WidgetDropDown::OnRender()
 		// Scroll selected element into view, if we have one
 		if (selection != -1)
 		{
-			Rml::ScrollIntoViewOptions scrollOptions {
-				box_layout_dirty == DropDownBoxLayoutType::Open ? Rml::ScrollAlignment::Start : Rml::ScrollAlignment::Nearest
+			ScrollIntoViewOptions scroll_options = {
+				box_opened_since_last_format ? ScrollAlignment::Center : ScrollAlignment::Nearest,
+				ScrollAlignment::Nearest,
+				ScrollBehavior::Instant,
 			};
-			GetOption(selection)->ScrollIntoView(scrollOptions);
+			GetOption(selection)->ScrollIntoView(scroll_options);
 		}
-
-		box_layout_dirty = DropDownBoxLayoutType::None;
+		box_opened_since_last_format = false;
+		box_layout_dirty = false;
 	}
 
 	if (value_layout_dirty)
@@ -278,7 +281,7 @@ void WidgetDropDown::OnLayout()
 	value_element->SetOffset(parent_element->GetBox().GetPosition(BoxArea::Content), parent_element);
 	value_element->SetBox(Box(size));
 
-	box_layout_dirty = DropDownBoxLayoutType::Switch;
+	box_layout_dirty = true;
 	value_layout_dirty = true;
 }
 
@@ -460,7 +463,7 @@ void WidgetDropDown::OnChildAdd(Element* element)
 		SetSelection(element, true);
 
 	selection_dirty = true;
-	box_layout_dirty = DropDownBoxLayoutType::Switch;
+	box_layout_dirty = true;
 }
 
 void WidgetDropDown::OnChildRemove(Element* element)
@@ -474,7 +477,7 @@ void WidgetDropDown::OnChildRemove(Element* element)
 		SetSelection(nullptr);
 
 	selection_dirty = true;
-	box_layout_dirty = DropDownBoxLayoutType::Switch;
+	box_layout_dirty = true;
 }
 
 void WidgetDropDown::AttachScrollEvent()
@@ -629,7 +632,8 @@ void WidgetDropDown::ShowSelectBox()
 	selection_element->SetPseudoClass("checked", true);
 	value_element->SetPseudoClass("checked", true);
 	button_element->SetPseudoClass("checked", true);
-	box_layout_dirty = DropDownBoxLayoutType::Open;
+	box_layout_dirty = true;
+	box_opened_since_last_format = true;
 	AttachScrollEvent();
 
 	box_visible = true;

Source/Core/Elements/WidgetDropDown.h

@@ -40,12 +40,6 @@ class ElementFormControl;
     @author Lloyd Weehuizen
  */
 
-enum class DropDownBoxLayoutType {
-	None,
-	Open,  // we just opened the drop-down menu
-	Switch // we're switching the selected value
-};
-
 class WidgetDropDown : public EventListener {
 public:
 	WidgetDropDown(ElementFormControl* element);
@@ -105,7 +99,7 @@ class WidgetDropDown : public EventListener {
 
 	/// Processes the incoming event.
 	void ProcessEvent(Event& event) override;
-	
+
 	/// Shows the selection box.
 	void ShowSelectBox();
 	/// Hides the selection box.
@@ -114,7 +108,6 @@ class WidgetDropDown : public EventListener {
 	bool IsSelectBoxVisible();
 
 private:
-
 	void AttachScrollEvent();
 	void DetachScrollEvent();
 
@@ -130,7 +123,8 @@ class WidgetDropDown : public EventListener {
 	bool selection_dirty;
 	bool value_rml_dirty;
 	bool value_layout_dirty;
-	DropDownBoxLayoutType box_layout_dirty;
+	bool box_layout_dirty;
+	bool box_opened_since_last_format;
 	bool box_visible;
 };