ListBox: tweaked default height calculation. simplifying code internally (rework passing of full rect). Should have no visible side-effects + misc comments.
// FIXME: In principle this function should be called BeginListBox(). We should rename it after re-evaluating if we want to keep the same signature.
// Helper to calculate the size of a listbox and display a label on the right.
// Tip: To have a list filling the entire window width, PushItemWidth(-1) and pass an non-visible label e.g. "##empty"
// 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).
// We add +25% worth of item height to allow the user to see at a glance if there are more items up/down, without looking at the scrollbar.
// We don't add this extra bit if items_count <= height_in_items. It is slightly dodgy, because it means a dynamic list of items will make the widget resize occasionally when it crosses that size.
// I am expecting that someone will come and complain about this behavior in a remote future, then we can advise on a better solution.
// We include ItemSpacing.y so that a list sized for the exact number of items doesn't make a scrollbar appears. We could also enforce that by passing a flag to BeginChild().
// FIXME: In principle this function should be called EndListBox(). We should rename it after re-evaluating if we want to keep the same signature.
voidImGui::ListBoxFooter()
{
ImGuiWindow*window=GetCurrentWindow();
ImGuiContext&g=*GImGui;
ImGuiWindow*window=g.CurrentWindow;
IM_ASSERT((window->Flags&ImGuiWindowFlags_ChildWindow)&&"Mismatched ListBoxHeader/ListBoxFooter calls. Did you test the return value of ListBoxHeader()?");
ImGuiWindow*parent_window=window->ParentWindow;
constImRectbb=parent_window->DC.LastItemRect;
constImGuiStyle&style=GetStyle();
EndChildFrame();
// Redeclare item size so that it includes the label (we have stored the full size in LastItemRect)
// We call SameLine() to restore DC.CurrentLine* data
SameLine();
parent_window->DC.CursorPos=bb.Min;
ItemSize(bb,style.FramePadding.y);
EndGroup();
EndGroup();// This is only required to be able to do IsItemXXX query on the whole ListBox including label
// Assume all items have even height (= 1 line of text). If you need items of different or variable sizes you can create a custom version of ListBox() in your code without using the clipper.
// Assume all items have even height (= 1 line of text). If you need items of different height,
// you can create a custom version of ListBox() in your code without using the clipper.
ocornut
4 years ago