Method TreeNodeBehavior

src/imgui/imgui_widgets.cpp:6755–7034

When using public API, currently 'id == storage_id' is always true, but we separate the values to facilitate advanced user code doing storage queries outside of UI loop.

// When using public API, currently 'id == storage_id' is always true, but we separate the values to facilitate advanced user code doing storage queries outside of UI loop.
bool ImGui::TreeNodeBehavior(ImGuiID id, ImGuiTreeNodeFlags flags, const char* label, const char* label_end)
{
    ImGuiWindow* window = GetCurrentWindow();
    if (window->SkipItems)
        return false;

    ImGuiContext& g = *GImGui;
    const ImGuiStyle& style = g.Style;
    const bool display_frame = (flags & ImGuiTreeNodeFlags_Framed) != 0;
    const ImVec2 padding = (display_frame || (flags & ImGuiTreeNodeFlags_FramePadding)) ? style.FramePadding : ImVec2(style.FramePadding.x, ImMin(window->DC.CurrLineTextBaseOffset, style.FramePadding.y));

    if (!label_end)
        label_end = FindRenderedTextEnd(label);
    const ImVec2 label_size = CalcTextSize(label, label_end, false);

    const float text_offset_x = g.FontSize + (display_frame ? padding.x * 3 : padding.x * 2);   // Collapsing arrow width + Spacing
    const float text_offset_y = ImMax(padding.y, window->DC.CurrLineTextBaseOffset);            // Latch before ItemSize changes it
    const float text_width = g.FontSize + label_size.x + padding.x * 2;                         // Include collapsing arrow

    // We vertically grow up to current line height up the typical widget height.
    const float frame_height = ImMax(ImMin(window->DC.CurrLineSize.y, g.FontSize + style.FramePadding.y * 2), label_size.y + padding.y * 2);
    const bool span_all_columns = (flags & ImGuiTreeNodeFlags_SpanAllColumns) != 0 && (g.CurrentTable != NULL);
    const bool span_all_columns_label = (flags & ImGuiTreeNodeFlags_LabelSpanAllColumns) != 0 && (g.CurrentTable != NULL);
    ImRect frame_bb;
    frame_bb.Min.x = span_all_columns ? window->ParentWorkRect.Min.x : (flags & ImGuiTreeNodeFlags_SpanFullWidth) ? window->WorkRect.Min.x : window->DC.CursorPos.x;
    frame_bb.Min.y = window->DC.CursorPos.y;
    frame_bb.Max.x = span_all_columns ? window->ParentWorkRect.Max.x : (flags & ImGuiTreeNodeFlags_SpanLabelWidth) ? window->DC.CursorPos.x + text_width + padding.x : window->WorkRect.Max.x;
    frame_bb.Max.y = window->DC.CursorPos.y + frame_height;
    if (display_frame)
    {
        const float outer_extend = IM_TRUNC(window->WindowPadding.x * 0.5f); // Framed header expand a little outside of current limits
        frame_bb.Min.x -= outer_extend;
        frame_bb.Max.x += outer_extend;
    }

    ImVec2 text_pos(window->DC.CursorPos.x + text_offset_x, window->DC.CursorPos.y + text_offset_y);
    ItemSize(ImVec2(text_width, frame_height), padding.y);

    // For regular tree nodes, we arbitrary allow to click past 2 worth of ItemSpacing
    ImRect interact_bb = frame_bb;
    if ((flags & (ImGuiTreeNodeFlags_Framed | ImGuiTreeNodeFlags_SpanAvailWidth | ImGuiTreeNodeFlags_SpanFullWidth | ImGuiTreeNodeFlags_SpanLabelWidth | ImGuiTreeNodeFlags_SpanAllColumns)) == 0)
        interact_bb.Max.x = frame_bb.Min.x + text_width + (label_size.x > 0.0f ? style.ItemSpacing.x * 2.0f : 0.0f);

    // Compute open and multi-select states before ItemAdd() as it clear NextItem data.
    ImGuiID storage_id = (g.NextItemData.HasFlags & ImGuiNextItemDataFlags_HasStorageID) ? g.NextItemData.StorageId : id;
    bool is_open = TreeNodeUpdateNextOpen(storage_id, flags);

    bool is_visible;
    if (span_all_columns || span_all_columns_label)
    {
        // Modify ClipRect for the ItemAdd(), faster than doing a PushColumnsBackground/PushTableBackgroundChannel for every Selectable..
        const float backup_clip_rect_min_x = window->ClipRect.Min.x;
        const float backup_clip_rect_max_x = window->ClipRect.Max.x;
        window->ClipRect.Min.x = window->ParentWorkRect.Min.x;
        window->ClipRect.Max.x = window->ParentWorkRect.Max.x;
        is_visible = ItemAdd(interact_bb, id);
        window->ClipRect.Min.x = backup_clip_rect_min_x;
        window->ClipRect.Max.x = backup_clip_rect_max_x;