Method BeginGroup

imgui_tiny_app/imgui/imgui.cpp:12356–12384

Lock horizontal starting position + capture group bounding box into one "item" (so you can use IsItemHovered() or layout primitives such as SameLine() on whole group, etc.) Groups are currently a mishmash of functionalities which should perhaps be clarified and separated. FIXME-OPT: Could we safely early out on ->SkipItems?

// Groups are currently a mishmash of functionalities which should perhaps be clarified and separated.
// FIXME-OPT: Could we safely early out on ->SkipItems?
void ImGui::BeginGroup()
{
    ImGuiContext& g = *GImGui;
    ImGuiWindow* window = g.CurrentWindow;

    g.GroupStack.resize(g.GroupStack.Size + 1);
    ImGuiGroupData& group_data = g.GroupStack.back();
    group_data.WindowID = window->ID;
    group_data.BackupCursorPos = window->DC.CursorPos;
    group_data.BackupCursorPosPrevLine = window->DC.CursorPosPrevLine;
    group_data.BackupCursorMaxPos = window->DC.CursorMaxPos;
    group_data.BackupIndent = window->DC.Indent;
    group_data.BackupGroupOffset = window->DC.GroupOffset;
    group_data.BackupCurrLineSize = window->DC.CurrLineSize;
    group_data.BackupCurrLineTextBaseOffset = window->DC.CurrLineTextBaseOffset;
    group_data.BackupActiveIdIsAlive = g.ActiveIdIsAlive;
    group_data.BackupHoveredIdIsAlive = g.HoveredId != 0;
    group_data.BackupIsSameLine = window->DC.IsSameLine;
    group_data.BackupActiveIdHasBeenEditedThisFrame = g.ActiveIdHasBeenEditedThisFrame;
    group_data.BackupDeactivatedIdIsAlive = g.DeactivatedItemData.IsAlive;
    group_data.EmitItem = true;

    window->DC.GroupOffset.x = window->DC.CursorPos.x - window->Pos.x - window->DC.ColumnsOffset.x;
    window->DC.Indent = window->DC.GroupOffset;
    window->DC.CursorMaxPos = window->DC.CursorPos;
    window->DC.CurrLineSize = ImVec2(0.0f, 0.0f);
    if (g.LogEnabled)
        g.LogLinePosY = -FLT_MAX; // To enforce a carriage return
}

void ImGui::EndGroup()
{