Method ControlOverrideBkColor

source/script_gui.cpp:9827–9849

GuiControlType *GuiType::ControlOverrideBkColor(GuiControlType &aControl)
// Caller has ensured that aControl.type is something for which the window's or tab control's background
// should apply (e.g. Progress or Text).
{
	GuiControlType *ptab_control;
	if (!mTabControlCount || !(ptab_control = FindTabControl(aControl.tab_control_index))
		|| ptab_control->background_color == CLR_INVALID) // Relies on short-circuit boolean order.
		return NULL;  // Override not needed because control isn't on a tab, or it's tab has same color as window.
	if (GetParent(aControl.hwnd) != mHwnd)
		// Even if the control doesn't lie entirely within the tab control's display area,
		// it is only visible within that area due to the parent-child relationship.
		return ptab_control;
	// Does this control lie mostly inside the tab?  Note that controls can belong to a tab page even though
	// they aren't physically located inside the page.
	RECT overlap_rect, tab_rect, control_rect;
	GetWindowRect(ptab_control->hwnd, &tab_rect);
	GetWindowRect(aControl.hwnd, &control_rect);
	IntersectRect(&overlap_rect, &tab_rect, &control_rect);
	// Returns true if more than 50% of control's area is inside the tab:
	return (overlap_rect.right - overlap_rect.left) * (overlap_rect.bottom - overlap_rect.top)
		> 0.5 * (control_rect.right - control_rect.left) * (control_rect.bottom - control_rect.top)
		? ptab_control : NULL;
}