Method DockNodeTreeUpdateSplitter

imgui_tiny_app/imgui/imgui.cpp:20304–20419

(Depth-First, Pre-Order)

// (Depth-First, Pre-Order)
void ImGui::DockNodeTreeUpdateSplitter(ImGuiDockNode* node)
{
    if (node->IsLeafNode())
        return;

    ImGuiContext& g = *GImGui;

    ImGuiDockNode* child_0 = node->ChildNodes[0];
    ImGuiDockNode* child_1 = node->ChildNodes[1];
    if (child_0->IsVisible && child_1->IsVisible)
    {
        // Bounding box of the splitter cover the space between both nodes (w = Spacing, h = Size[xy^1] for when splitting horizontally)
        const ImGuiAxis axis = (ImGuiAxis)node->SplitAxis;
        IM_ASSERT(axis != ImGuiAxis_None);
        ImRect bb;
        bb.Min = child_0->Pos;
        bb.Max = child_1->Pos;
        bb.Min[axis] += child_0->Size[axis];
        bb.Max[axis ^ 1] += child_1->Size[axis ^ 1];
        //if (g.IO.KeyCtrl) GetForegroundDrawList(g.CurrentWindow->Viewport)->AddRect(bb.Min, bb.Max, IM_COL32(255,0,255,255));

        const ImGuiDockNodeFlags merged_flags = child_0->MergedFlags | child_1->MergedFlags; // Merged flags for BOTH childs
        const ImGuiDockNodeFlags no_resize_axis_flag = (axis == ImGuiAxis_X) ? ImGuiDockNodeFlags_NoResizeX : ImGuiDockNodeFlags_NoResizeY;
        if ((merged_flags & ImGuiDockNodeFlags_NoResize) || (merged_flags & no_resize_axis_flag))
        {
            ImGuiWindow* window = g.CurrentWindow;
            window->DrawList->AddRectFilled(bb.Min, bb.Max, GetColorU32(ImGuiCol_Separator), g.Style.FrameRounding);
        }
        else
        {
            //bb.Min[axis] += 1; // Display a little inward so highlight doesn't connect with nearby tabs on the neighbor node.
            //bb.Max[axis] -= 1;
            PushID(node->ID);

            // Find resizing limits by gathering list of nodes that are touching the splitter line.
            ImVector<ImGuiDockNode*> touching_nodes[2];
            float min_size = g.Style.WindowMinSize[axis];
            float resize_limits[2];
            resize_limits[0] = node->ChildNodes[0]->Pos[axis] + min_size;
            resize_limits[1] = node->ChildNodes[1]->Pos[axis] + node->ChildNodes[1]->Size[axis] - min_size;

            ImGuiID splitter_id = GetID("##Splitter");
            if (g.ActiveId == splitter_id) // Only process when splitter is active
            {
                DockNodeTreeUpdateSplitterFindTouchingNode(child_0, axis, 1, &touching_nodes[0]);
                DockNodeTreeUpdateSplitterFindTouchingNode(child_1, axis, 0, &touching_nodes[1]);
                for (int touching_node_n = 0; touching_node_n < touching_nodes[0].Size; touching_node_n++)
                    resize_limits[0] = ImMax(resize_limits[0], touching_nodes[0][touching_node_n]->Rect().Min[axis] + min_size);
                for (int touching_node_n = 0; touching_node_n < touching_nodes[1].Size; touching_node_n++)
                    resize_limits[1] = ImMin(resize_limits[1], touching_nodes[1][touching_node_n]->Rect().Max[axis] - min_size);

                // [DEBUG] Render touching nodes & limits
                /*
                ImDrawList* draw_list = node->HostWindow ? GetForegroundDrawList(node->HostWindow) : GetForegroundDrawList(GetMainViewport());
                for (int n = 0; n < 2; n++)
                {
                    for (int touching_node_n = 0; touching_node_n < touching_nodes[n].Size; touching_node_n++)
                        draw_list->AddRect(touching_nodes[n][touching_node_n]->Pos, touching_nodes[n][touching_node_n]->Pos + touching_nodes[n][touching_node_n]->Size, IM_COL32(0, 255, 0, 255));