Method BeginListBox

KBotExt/imgui/imgui_widgets.cpp:6606–6643

Tip: To have a list filling the entire window width, use size.x = -FLT_MIN and pass an non-visible label e.g. "##empty" Tip: If your vertical size is calculated from an item count (e.g. 10 * item_height) consider adding a fractional part to facilitate seeing scrolling boundaries (e.g. 10.25 * item_height).

// Tip: To have a list filling the entire window width, use size.x = -FLT_MIN and pass an non-visible label e.g. "##empty"
// Tip: If your vertical size is calculated from an item count (e.g. 10 * item_height) consider adding a fractional part to facilitate seeing scrolling boundaries (e.g. 10.25 * item_height).
bool ImGui::BeginListBox(const char* label, const ImVec2& size_arg)
{
	ImGuiContext& g = *GImGui;
	ImGuiWindow* window = GetCurrentWindow();
	if (window->SkipItems)
		return false;

	const ImGuiStyle& style = g.Style;
	const ImGuiID id = GetID(label);
	const ImVec2 label_size = CalcTextSize(label, NULL, true);

	// Size default to hold ~7.25 items.
	// Fractional number of items helps seeing that we can scroll down/up without looking at scrollbar.
	ImVec2 size = ImFloor(CalcItemSize(size_arg, CalcItemWidth(), GetTextLineHeightWithSpacing() * 7.25f + style.FramePadding.y * 2.0f));
	ImVec2 frame_size = ImVec2(size.x, ImMax(size.y, label_size.y));
	ImRect frame_bb(window->DC.CursorPos, window->DC.CursorPos + frame_size);
	ImRect bb(frame_bb.Min, frame_bb.Max + ImVec2(label_size.x > 0.0f ? style.ItemInnerSpacing.x + label_size.x : 0.0f, 0.0f));
	g.NextItemData.ClearFlags();

	if (!IsRectVisible(bb.Min, bb.Max))
	{
		ItemSize(bb.GetSize(), style.FramePadding.y);
		ItemAdd(bb, 0, &frame_bb);
		return false;
	}

	// FIXME-OPT: We could omit the BeginGroup() if label_size.x but would need to omit the EndGroup() as well.
	BeginGroup();
	if (label_size.x > 0.0f)
	{
		ImVec2 label_pos = ImVec2(frame_bb.Max.x + style.ItemInnerSpacing.x, frame_bb.Min.y + style.FramePadding.y);
		RenderText(label_pos, label);
		window->DC.CursorMaxPos = ImMax(window->DC.CursorMaxPos, label_pos + label_size);
	}

	BeginChildFrame(id, frame_bb.GetSize());
	return true;
}

void ImGui::EndListBox()
{