Method TableUpdateLayout

src/imgui/imgui_tables.cpp:803–1281

Layout columns for the frame. This is in essence the followup to BeginTable() and this is our largest function. Runs on the first call to TableNextRow(), to give a chance for TableSetupColumn() and other TableSetupXXXXX() functions to be called first. FIXME-TABLE: Our width (and therefore our WorkRect) will be minimal in the first frame for _WidthAuto columns. Increase feedback side-effect with wi

// FIXME-TABLE: Our width (and therefore our WorkRect) will be minimal in the first frame for _WidthAuto columns.
// Increase feedback side-effect with widgets relying on WorkRect.Max.x... Maybe provide a default distribution for _WidthAuto columns?
void ImGui::TableUpdateLayout(ImGuiTable* table)
{
    ImGuiContext& g = *GImGui;
    IM_ASSERT(table->IsLayoutLocked == false);

    const ImGuiTableFlags table_sizing_policy = (table->Flags & ImGuiTableFlags_SizingMask_);
    table->IsDefaultDisplayOrder = true;
    table->ColumnsEnabledCount = 0;
    ImBitArrayClearAllBits(table->EnabledMaskByIndex, table->ColumnsCount);
    ImBitArrayClearAllBits(table->EnabledMaskByDisplayOrder, table->ColumnsCount);
    table->LeftMostEnabledColumn = -1;
    table->MinColumnWidth = ImMax(1.0f, g.Style.FramePadding.x * 1.0f); // g.Style.ColumnsMinSpacing; // FIXME-TABLE

    // [Part 1] Apply/lock Enabled and Order states. Calculate auto/ideal width for columns. Count fixed/stretch columns.
    // Process columns in their visible orders as we are building the Prev/Next indices.
    int count_fixed = 0;                // Number of columns that have fixed sizing policies
    int count_stretch = 0;              // Number of columns that have stretch sizing policies
    int prev_visible_column_idx = -1;
    bool has_auto_fit_request = false;
    bool has_resizable = false;
    float stretch_sum_width_auto = 0.0f;
    float fixed_max_width_auto = 0.0f;
    for (int order_n = 0; order_n < table->ColumnsCount; order_n++)
    {
        const int column_n = table->DisplayOrderToIndex[order_n];
        if (column_n != order_n)
            table->IsDefaultDisplayOrder = false;
        ImGuiTableColumn* column = &table->Columns[column_n];

        // Clear column setup if not submitted by user. Currently we make it mandatory to call TableSetupColumn() every frame.
        // It would easily work without but we're not ready to guarantee it since e.g. names need resubmission anyway.
        // We take a slight shortcut but in theory we could be calling TableSetupColumn() here with dummy values, it should yield the same effect.
        if (table->DeclColumnsCount <= column_n)
        {
            TableSetupColumnFlags(table, column, ImGuiTableColumnFlags_None);
            column->NameOffset = -1;
            column->UserID = 0;
            column->InitStretchWeightOrWidth = -1.0f;
        }

        // Update Enabled state, mark settings and sort specs dirty
        if (!(table->Flags & ImGuiTableFlags_Hideable) || (column->Flags & ImGuiTableColumnFlags_NoHide))
            column->IsUserEnabledNextFrame = true;
        if (column->IsUserEnabled != column->IsUserEnabledNextFrame)
        {
            column->IsUserEnabled = column->IsUserEnabledNextFrame;
            table->IsSettingsDirty = true;
        }
        column->IsEnabled = column->IsUserEnabled && (column->Flags & ImGuiTableColumnFlags_Disabled) == 0;

        if (column->SortOrder != -1 && !column->IsEnabled)
            table->IsSortSpecsDirty = true;
        if (column->SortOrder > 0 && !(table->Flags & ImGuiTableFlags_SortMulti))
            table->IsSortSpecsDirty = true;

        // Auto-fit unsized columns
        const bool start_auto_fit = (column->Flags & ImGuiTableColumnFlags_WidthFixed) ? (column->WidthRequest < 0.0f) : (column->StretchWeight < 0.0f);
        if (start_auto_fit)