Method TableUpdateLayout

ImGUI GLFW Tutorial/imgui/imgui_tables.cpp:719–1132

Layout columns for the frame. This is in essence the followup to BeginTable(). Runs on the first call to TableNextRow(), to give a chance for TableSetupColumn() 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 widgets relying on WorkRect.Max.x... Maybe provide a default distribution

// 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;
    table->EnabledMaskByIndex = 0x00;
    table->EnabledMaskByDisplayOrder = 0x00;
    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/sortspecs dirty
        if (!(table->Flags & ImGuiTableFlags_Hideable) || (column->Flags & ImGuiTableColumnFlags_NoHide))
            column->IsEnabledNextFrame = true;
        if (column->IsEnabled != column->IsEnabledNextFrame)
        {
            column->IsEnabled = column->IsEnabledNextFrame;
            table->IsSettingsDirty = true;
            if (!column->IsEnabled && column->SortOrder != -1)
                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)
            column->AutoFitQueue = column->CannotSkipItemsQueue = (1 << 3) - 1; // Fit for three frames