Changeset - r28260:9b156672a764
[Not reviewed]
master
0 1 0
Peter Nelson - 12 months ago 2023-12-07 12:44:25
peter1138@openttd.org
Codechange: Move dropdown list size and position calculation to window.

This simplifies initialization of DropdownWindow, as instead of both the caller code and the class needing to know about list sizes and available space, only the DropdownWindow needs to know.
1 file changed with 78 insertions and 85 deletions:
0 comments (0 inline, 0 general)
src/widgets/dropdown.cpp
Show inline comments
 
@@ -24,7 +24,7 @@
 

	
 
static const NWidgetPart _nested_dropdown_menu_widgets[] = {
 
	NWidget(NWID_HORIZONTAL),
 
		NWidget(WWT_PANEL, COLOUR_END, WID_DM_ITEMS), SetMinimalSize(1, 1), SetScrollbar(WID_DM_SCROLL), EndContainer(),
 
		NWidget(WWT_PANEL, COLOUR_END, WID_DM_ITEMS), SetScrollbar(WID_DM_SCROLL), EndContainer(),
 
		NWidget(NWID_SELECTION, INVALID_COLOUR, WID_DM_SHOW_SCROLL),
 
			NWidget(NWID_VSCROLLBAR, COLOUR_END, WID_DM_SCROLL),
 
		EndContainer(),
 
@@ -41,6 +41,7 @@ static WindowDesc _dropdown_desc(__FILE_
 
/** Drop-down menu window */
 
struct DropdownWindow : Window {
 
	int parent_button;            ///< Parent widget number where the window is dropped from.
 
	Rect wi_rect;                 ///< Rect of the button that opened the dropdown.
 
	const DropDownList list;      ///< List with dropdown menu items.
 
	int selected_result;          ///< Result value of the selected item in the list.
 
	byte click_delay = 0;         ///< Timer to delay selection.
 
@@ -50,25 +51,25 @@ struct DropdownWindow : Window {
 
	Point position;               ///< Position of the topleft corner of the window.
 
	Scrollbar *vscroll;
 

	
 
	Dimension items_dim; ///< Calculated cropped and padded dimension for the items widget.
 

	
 
	/**
 
	 * Create a dropdown menu.
 
	 * @param parent        Parent window.
 
	 * @param list          Dropdown item list.
 
	 * @param selected      Initial selected result of the list.
 
	 * @param button        Widget of the parent window doing the dropdown.
 
	 * @param wi_rect       Rect of the button that opened the dropdown.
 
	 * @param instant_close Close the window when the mouse button is raised.
 
	 * @param position      Topleft position of the dropdown menu window.
 
	 * @param size          Size of the dropdown menu window.
 
	 * @param wi_colour     Colour of the parent widget.
 
	 * @param scroll        Dropdown menu has a scrollbar.
 
	 */
 
	DropdownWindow(Window *parent, DropDownList &&list, int selected, int button, bool instant_close, const Point &position, const Dimension &size, Colours wi_colour, bool scroll)
 
	DropdownWindow(Window *parent, DropDownList &&list, int selected, int button, const Rect wi_rect, bool instant_close, Colours wi_colour)
 
			: Window(&_dropdown_desc)
 
			, parent_button(button)
 
			, wi_rect(wi_rect)
 
			, list(std::move(list))
 
			, selected_result(selected)
 
			, instant_close(instant_close)
 
			, position(position)
 
	{
 
		assert(!this->list.empty());
 

	
 
@@ -76,30 +77,13 @@ struct DropdownWindow : Window {
 

	
 
		this->CreateNestedTree();
 

	
 
		this->GetWidget<NWidgetCore>(WID_DM_ITEMS)->colour = wi_colour;
 
		this->GetWidget<NWidgetCore>(WID_DM_SCROLL)->colour = wi_colour;
 
		this->vscroll = this->GetScrollbar(WID_DM_SCROLL);
 

	
 
		uint items_width = size.width - (scroll ? NWidgetScrollbar::GetVerticalDimension().width : 0);
 
		NWidgetCore *nwi = this->GetWidget<NWidgetCore>(WID_DM_ITEMS);
 
		nwi->SetMinimalSizeAbsolute(items_width, size.height + WidgetDimensions::scaled.dropdownlist.Vertical());
 
		nwi->colour = wi_colour;
 

	
 
		nwi = this->GetWidget<NWidgetCore>(WID_DM_SCROLL);
 
		nwi->colour = wi_colour;
 

	
 
		this->GetWidget<NWidgetStacked>(WID_DM_SHOW_SCROLL)->SetDisplayedPlane(scroll ? 0 : SZSP_NONE);
 
		this->UpdateSizeAndPosition();
 

	
 
		this->FinishInitNested(0);
 
		CLRBITS(this->flags, WF_WHITE_BORDER);
 

	
 
		/* Total length of list */
 
		int list_height = 0;
 
		for (const auto &item : this->list) {
 
			list_height += item->Height();
 
		}
 

	
 
		/* Capacity is the average number of items visible */
 
		this->vscroll->SetCapacity(size.height * this->list.size() / list_height);
 
		this->vscroll->SetCount(this->list.size());
 
	}
 

	
 
	void Close([[maybe_unused]] int data = 0) override
 
@@ -126,6 +110,73 @@ struct DropdownWindow : Window {
 
		}
 
	}
 

	
 
	/**
 
	 * Fit dropdown list into available height, rounding to average item size. Width is adjusted if scrollbar is present.
 
	 * @param[in,out] desired Desired dimensions of dropdown list.
 
	 * @param list Dimensions of the list itself, without padding or cropping.
 
	 * @param available_height Available height to fit list within.
 
	 */
 
	void FitAvailableHeight(Dimension &desired, const Dimension &list, uint available_height)
 
	{
 
		if (desired.height < available_height) return;
 

	
 
		/* If the dropdown doesn't fully fit, we a need a dropdown. */
 
		uint avg_height = list.height / (uint)this->list.size();
 
		uint rows = std::max((available_height - WidgetDimensions::scaled.dropdownlist.Vertical()) / avg_height, 1U);
 

	
 
		desired.width = std::max(list.width, desired.width - NWidgetScrollbar::GetVerticalDimension().width);
 
		desired.height = rows * avg_height + WidgetDimensions::scaled.dropdownlist.Vertical();
 
	}
 

	
 
	/**
 
	 * Update size and position of window to fit dropdown list into available space.
 
	 */
 
	void UpdateSizeAndPosition()
 
	{
 
		Rect button_rect = this->wi_rect.Translate(this->parent->left, this->parent->top);
 

	
 
		/* Get the dimensions required for the list. */
 
		Dimension list_dim = GetDropDownListDimension(this->list);
 

	
 
		/* Set up dimensions for the items widget. */
 
		Dimension widget_dim = list_dim;
 
		widget_dim.width += WidgetDimensions::scaled.dropdownlist.Horizontal();
 
		widget_dim.height += WidgetDimensions::scaled.dropdownlist.Vertical();
 

	
 
		/* Width should match at least the width of the parent widget. */
 
		widget_dim.width = std::max<uint>(widget_dim.width, button_rect.Width());
 

	
 
		/* Available height below (or above, if the dropdown is placed above the widget). */
 
		uint available_height_below = std::max(GetMainViewBottom() - button_rect.bottom - 1, 0);
 
		uint available_height_above = std::max(button_rect.top - 1 - GetMainViewTop(), 0);
 

	
 
		/* Is it better to place the dropdown above the widget? */
 
		if (widget_dim.height > available_height_below && available_height_above > available_height_below) {
 
			FitAvailableHeight(widget_dim, list_dim, available_height_above);
 
			this->position.y = button_rect.top - widget_dim.height;
 
		} else {
 
			FitAvailableHeight(widget_dim, list_dim, available_height_below);
 
			this->position.y = button_rect.bottom + 1;
 
		}
 

	
 
		this->position.x = (_current_text_dir == TD_RTL) ? button_rect.right + 1 - (int)widget_dim.width : button_rect.left;
 

	
 
		this->items_dim = widget_dim;
 
		this->GetWidget<NWidgetStacked>(WID_DM_SHOW_SCROLL)->SetDisplayedPlane(list_dim.height > widget_dim.height ? 0 : SZSP_NONE);
 

	
 
		/* Capacity is the average number of items visible */
 
		this->vscroll->SetCapacity((widget_dim.height - WidgetDimensions::scaled.dropdownlist.Vertical()) * this->list.size() / list_dim.height);
 
		this->vscroll->SetCount(this->list.size());
 

	
 
		/* If the dropdown is positioned above the parent widget, start selection at the bottom. */
 
		if (this->position.y < button_rect.top && list_dim.height > widget_dim.height) this->vscroll->UpdatePosition(INT_MAX);
 
	}
 

	
 
	void UpdateWidgetSize(int widget, Dimension *size, [[maybe_unused]] const Dimension &padding, [[maybe_unused]] Dimension *fill, [[maybe_unused]] Dimension *resize) override
 
	{
 
		if (widget == WID_DM_ITEMS) *size = this->items_dim;
 
	}
 

	
 
	Point OnInitialPosition([[maybe_unused]] int16_t sm_width, [[maybe_unused]] int16_t sm_height, [[maybe_unused]] int window_number) override
 
	{
 
		return this->position;
 
@@ -281,65 +332,7 @@ Dimension GetDropDownListDimension(const
 
void ShowDropDownListAt(Window *w, DropDownList &&list, int selected, int button, Rect wi_rect, Colours wi_colour, bool instant_close)
 
{
 
	CloseWindowByClass(WC_DROPDOWN_MENU);
 

	
 
	/* The preferred position is just below the dropdown calling widget */
 
	int top = w->top + wi_rect.bottom + 1;
 

	
 
	/* The preferred width equals the calling widget */
 
	uint width = wi_rect.Width();
 

	
 
	/* Get the height and width required for the list. */
 
	Dimension dim = GetDropDownListDimension(list);
 
	dim.width += WidgetDimensions::scaled.dropdownlist.Horizontal();
 

	
 
	/* Scrollbar needed? */
 
	bool scroll = false;
 

	
 
	/* Is it better to place the dropdown above the widget? */
 
	bool above = false;
 

	
 
	/* Available height below (or above, if the dropdown is placed above the widget). */
 
	uint available_height = std::max(GetMainViewBottom() - top - (int)WidgetDimensions::scaled.dropdownlist.Vertical(), 0);
 

	
 
	/* If the dropdown doesn't fully fit below the widget... */
 
	if (dim.height > available_height) {
 

	
 
		uint available_height_above = std::max(w->top + wi_rect.top - GetMainViewTop() - (int)WidgetDimensions::scaled.dropdownlist.Vertical(), 0);
 

	
 
		/* Put the dropdown above if there is more available space. */
 
		if (available_height_above > available_height) {
 
			above = true;
 
			available_height = available_height_above;
 
		}
 

	
 
		/* If the dropdown doesn't fully fit, we need a dropdown. */
 
		if (dim.height > available_height) {
 
			scroll = true;
 
			uint avg_height = dim.height / (uint)list.size();
 

	
 
			/* Fit the list; create at least one row, even if there is no height available. */
 
			uint rows = std::max<uint>(available_height / avg_height, 1);
 
			dim.height = rows * avg_height;
 

	
 
			/* Add space for the scrollbar. */
 
			dim.width += NWidgetScrollbar::GetVerticalDimension().width;
 
		}
 

	
 
		/* Set the top position if needed. */
 
		if (above) {
 
			top = w->top + wi_rect.top - dim.height - WidgetDimensions::scaled.dropdownlist.Vertical();
 
		}
 
	}
 

	
 
	dim.width = std::max(width, dim.width);
 

	
 
	Point dw_pos = { w->left + (_current_text_dir == TD_RTL ? wi_rect.right + 1 - (int)width : wi_rect.left), top};
 
	DropdownWindow *dropdown = new DropdownWindow(w, std::move(list), selected, button, instant_close, dw_pos, dim, wi_colour, scroll);
 

	
 
	/* The dropdown starts scrolling downwards when opening it towards
 
	 * the top and holding down the mouse button. It can be fooled by
 
	 * opening the dropdown scrolled to the very bottom.  */
 
	if (above && scroll) dropdown->vscroll->UpdatePosition(INT_MAX);
 
	new DropdownWindow(w, std::move(list), selected, button, wi_rect, instant_close, wi_colour);
 
}
 

	
 
/**
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