Method DockContextProcessDock

imgui_tiny_app/imgui/imgui.cpp:18280–18416

}

void ImGui::DockContextProcessDock(ImGuiContext* ctx, ImGuiDockRequest* req)
{
    IM_ASSERT((req->Type == ImGuiDockRequestType_Dock && req->DockPayload != NULL) || (req->Type == ImGuiDockRequestType_Split && req->DockPayload == NULL));
    IM_ASSERT(req->DockTargetWindow != NULL || req->DockTargetNode != NULL);

    ImGuiContext& g = *ctx;
    IM_UNUSED(g);

    ImGuiWindow* payload_window = req->DockPayload;     // Optional
    ImGuiWindow* target_window = req->DockTargetWindow;
    ImGuiDockNode* node = req->DockTargetNode;
    if (payload_window)
        IMGUI_DEBUG_LOG_DOCKING("[docking] DockContextProcessDock node 0x%08X target '%s' dock window '%s', split_dir %d\n", node ? node->ID : 0, target_window ? target_window->Name : "NULL", payload_window->Name, req->DockSplitDir);
    else
        IMGUI_DEBUG_LOG_DOCKING("[docking] DockContextProcessDock node 0x%08X, split_dir %d\n", node ? node->ID : 0, req->DockSplitDir);

    // Decide which Tab will be selected at the end of the operation
    ImGuiID next_selected_id = 0;
    ImGuiDockNode* payload_node = NULL;
    if (payload_window)
    {
        payload_node = payload_window->DockNodeAsHost;
        payload_window->DockNodeAsHost = NULL; // Important to clear this as the node will have its life as a child which might be merged/deleted later.
        if (payload_node && payload_node->IsLeafNode())
            next_selected_id = payload_node->TabBar->NextSelectedTabId ? payload_node->TabBar->NextSelectedTabId : payload_node->TabBar->SelectedTabId;
        if (payload_node == NULL)
            next_selected_id = payload_window->TabId;
    }

    // FIXME-DOCK: When we are trying to dock an existing single-window node into a loose window, transfer Node ID as well
    // When processing an interactive split, usually LastFrameAlive will be < g.FrameCount. But DockBuilder operations can make it ==.
    if (node)
        IM_ASSERT(node->LastFrameAlive <= g.FrameCount);
    if (node && target_window && node == target_window->DockNodeAsHost)
        IM_ASSERT(node->Windows.Size > 0 || node->IsSplitNode() || node->IsCentralNode());

    // Create new node and add existing window to it
    if (node == NULL)
    {
        node = DockContextAddNode(ctx, 0);
        node->Pos = target_window->Pos;
        node->Size = target_window->Size;
        if (target_window->DockNodeAsHost == NULL)
        {
            DockNodeAddWindow(node, target_window, true);
            node->TabBar->Tabs[0].Flags &= ~ImGuiTabItemFlags_Unsorted;
            target_window->DockIsActive = true;
        }
    }

    ImGuiDir split_dir = req->DockSplitDir;
    if (split_dir != ImGuiDir_None)
    {
        // Split into two, one side will be our payload node unless we are dropping a loose window
        const ImGuiAxis split_axis = (split_dir == ImGuiDir_Left || split_dir == ImGuiDir_Right) ? ImGuiAxis_X : ImGuiAxis_Y;
        const int split_inheritor_child_idx = (split_dir == ImGuiDir_Left || split_dir == ImGuiDir_Up) ? 1 : 0; // Current contents will be moved to the opposite side
        const float split_ratio = req->DockSplitRatio;
        DockNodeTreeSplit(ctx, node, split_axis, split_inheritor_child_idx, split_ratio, payload_node);  // payload_node may be NULL here!