Function CalcWindowAutoFitSize

ImGUI GLFW Tutorial/imgui/imgui.cpp:5230–5266

}

static ImVec2 CalcWindowAutoFitSize(ImGuiWindow* window, const ImVec2& size_contents)
{
    ImGuiContext& g = *GImGui;
    ImGuiStyle& style = g.Style;
    const float decoration_up_height = window->TitleBarHeight() + window->MenuBarHeight();
    ImVec2 size_pad = window->WindowPadding * 2.0f;
    ImVec2 size_desired = size_contents + size_pad + ImVec2(0.0f, decoration_up_height);
    if (window->Flags & ImGuiWindowFlags_Tooltip)
    {
        // Tooltip always resize
        return size_desired;
    }
    else
    {
        // Maximum window size is determined by the viewport size or monitor size
        const bool is_popup = (window->Flags & ImGuiWindowFlags_Popup) != 0;
        const bool is_menu = (window->Flags & ImGuiWindowFlags_ChildMenu) != 0;
        ImVec2 size_min = style.WindowMinSize;
        if (is_popup || is_menu) // Popups and menus bypass style.WindowMinSize by default, but we give then a non-zero minimum size to facilitate understanding problematic cases (e.g. empty popups)
            size_min = ImMin(size_min, ImVec2(4.0f, 4.0f));

        // FIXME-VIEWPORT-WORKAREA: May want to use GetWorkSize() instead of Size depending on the type of windows?
        ImVec2 avail_size = ImGui::GetMainViewport()->Size;
        ImVec2 size_auto_fit = ImClamp(size_desired, size_min, ImMax(size_min, avail_size - style.DisplaySafeAreaPadding * 2.0f));

        // When the window cannot fit all contents (either because of constraints, either because screen is too small),
        // we are growing the size on the other axis to compensate for expected scrollbar. FIXME: Might turn bigger than ViewportSize-WindowPadding.
        ImVec2 size_auto_fit_after_constraint = CalcWindowSizeAfterConstraint(window, size_auto_fit);
        bool will_have_scrollbar_x = (size_auto_fit_after_constraint.x - size_pad.x - 0.0f                 < size_contents.x && !(window->Flags & ImGuiWindowFlags_NoScrollbar) && (window->Flags & ImGuiWindowFlags_HorizontalScrollbar)) || (window->Flags & ImGuiWindowFlags_AlwaysHorizontalScrollbar);
        bool will_have_scrollbar_y = (size_auto_fit_after_constraint.y - size_pad.y - decoration_up_height < size_contents.y && !(window->Flags & ImGuiWindowFlags_NoScrollbar)) || (window->Flags & ImGuiWindowFlags_AlwaysVerticalScrollbar);
        if (will_have_scrollbar_x)
            size_auto_fit.y += style.ScrollbarSize;
        if (will_have_scrollbar_y)
            size_auto_fit.x += style.ScrollbarSize;
        return size_auto_fit;
    }
}

ImVec2 ImGui::CalcWindowNextAutoFitSize(ImGuiWindow* window)
{