Method BeginColumns

extern/imgui/imgui_tables.cpp:3856–3931

}

void ImGui::BeginColumns(const char* str_id, int columns_count, ImGuiOldColumnFlags flags)
{
    ImGuiContext& g = *GImGui;
    ImGuiWindow* window = GetCurrentWindow();

    IM_ASSERT(columns_count >= 1);
    IM_ASSERT(window->DC.CurrentColumns == NULL);   // Nested columns are currently not supported

    // Acquire storage for the columns set
    ImGuiID id = GetColumnsID(str_id, columns_count);
    ImGuiOldColumns* columns = FindOrCreateColumns(window, id);
    IM_ASSERT(columns->ID == id);
    columns->Current = 0;
    columns->Count = columns_count;
    columns->Flags = flags;
    window->DC.CurrentColumns = columns;

    columns->HostCursorPosY = window->DC.CursorPos.y;
    columns->HostCursorMaxPosX = window->DC.CursorMaxPos.x;
    columns->HostInitialClipRect = window->ClipRect;
    columns->HostBackupParentWorkRect = window->ParentWorkRect;
    window->ParentWorkRect = window->WorkRect;

    // Set state for first column
    // We aim so that the right-most column will have the same clipping width as other after being clipped by parent ClipRect
    const float column_padding = g.Style.ItemSpacing.x;
    const float half_clip_extend_x = ImFloor(ImMax(window->WindowPadding.x * 0.5f, window->WindowBorderSize));
    const float max_1 = window->WorkRect.Max.x + column_padding - ImMax(column_padding - window->WindowPadding.x, 0.0f);
    const float max_2 = window->WorkRect.Max.x + half_clip_extend_x;
    columns->OffMinX = window->DC.Indent.x - column_padding + ImMax(column_padding - window->WindowPadding.x, 0.0f);
    columns->OffMaxX = ImMax(ImMin(max_1, max_2) - window->Pos.x, columns->OffMinX + 1.0f);
    columns->LineMinY = columns->LineMaxY = window->DC.CursorPos.y;

    // Clear data if columns count changed
    if (columns->Columns.Size != 0 && columns->Columns.Size != columns_count + 1)
        columns->Columns.resize(0);

    // Initialize default widths
    columns->IsFirstFrame = (columns->Columns.Size == 0);
    if (columns->Columns.Size == 0)
    {
        columns->Columns.reserve(columns_count + 1);
        for (int n = 0; n < columns_count + 1; n++)
        {
            ImGuiOldColumnData column;
            column.OffsetNorm = n / (float)columns_count;
            columns->Columns.push_back(column);
        }
    }

    for (int n = 0; n < columns_count; n++)
    {
        // Compute clipping rectangle
        ImGuiOldColumnData* column = &columns->Columns[n];
        float clip_x1 = IM_ROUND(window->Pos.x + GetColumnOffset(n));
        float clip_x2 = IM_ROUND(window->Pos.x + GetColumnOffset(n + 1) - 1.0f);
        column->ClipRect = ImRect(clip_x1, -FLT_MAX, clip_x2, +FLT_MAX);
        column->ClipRect.ClipWithFull(window->ClipRect);