Docking: Added experimental flags to perform more docking filtering and disable resize per axis. Designed for toolbar patterns.

The local/shared flags specs, saving and inheriting rules are pretty inconsistent at the moment.

imgui.cpp

@@ -13486,22 +13486,27 @@ static void ImGui::DockNodePreviewDockSetup(ImGuiWindow* host_window, ImGuiDockN
         IM_ASSERT(ref_node_for_rect->IsVisible);
 
     // Filter, figure out where we are allowed to dock
-    ImGuiDockNodeFlags host_node_flags = host_node ? host_node->GetMergedFlags() : 0;
+    ImGuiDockNodeFlags src_node_flags = root_payload_as_host ? root_payload_as_host->GetMergedFlags() : root_payload->WindowClass.DockNodeFlagsOverrideSet;
+    ImGuiDockNodeFlags dst_node_flags = host_node ? host_node->GetMergedFlags() : host_window->WindowClass.DockNodeFlagsOverrideSet;
     data->IsCenterAvailable = true;
     if (is_outer_docking)
         data->IsCenterAvailable = false;
-    else if (host_node && (host_node_flags & ImGuiDockNodeFlags_NoDocking))
+    else if (dst_node_flags & ImGuiDockNodeFlags_NoDocking)
         data->IsCenterAvailable = false;
-    else if (host_node && (host_node_flags & ImGuiDockNodeFlags_NoDockingInCentralNode) && host_node->IsCentralNode())
+    else if (host_node && (dst_node_flags & ImGuiDockNodeFlags_NoDockingInCentralNode) && host_node->IsCentralNode())
         data->IsCenterAvailable = false;
     else if ((!host_node || !host_node->IsEmpty()) && root_payload_as_host && root_payload_as_host->IsSplitNode() && (root_payload_as_host->OnlyNodeWithWindows == NULL)) // Is _visibly_ split?
         data->IsCenterAvailable = false;
+    else if ((dst_node_flags & ImGuiDockNodeFlags_NoDockingOverMe) || (src_node_flags & ImGuiDockNodeFlags_NoDockingOverOther))
+        data->IsCenterAvailable = false;
 
     data->IsSidesAvailable = true;
-    if ((host_node && (host_node_flags & ImGuiDockNodeFlags_NoSplit)) || g.IO.ConfigDockingNoSplit)
+    if ((dst_node_flags & ImGuiDockNodeFlags_NoSplit) || g.IO.ConfigDockingNoSplit)
         data->IsSidesAvailable = false;
     else if (!is_outer_docking && host_node && host_node->ParentNode == NULL && host_node->IsCentralNode())
         data->IsSidesAvailable = false;
+    else if ((dst_node_flags & ImGuiDockNodeFlags_NoDockingSplitMe) || (src_node_flags & ImGuiDockNodeFlags_NoDockingSplitOther))
+        data->IsSidesAvailable = false;
 
     // Build a tentative future node (reuse same structure because it is practical. Shape will be readjusted when previewing a split)
     data->FutureNode.HasCloseButton = (host_node ? host_node->HasCloseButton : host_window->HasCloseButton) || (root_payload->HasCloseButton);
@@ -13877,7 +13882,9 @@ void ImGui::DockNodeTreeUpdateSplitter(ImGuiDockNode* node)
         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));
 
-        if ((child_0->GetMergedFlags() | child_1->GetMergedFlags()) & ImGuiDockNodeFlags_NoResize)
+        const ImGuiDockNodeFlags merged_flags = child_0->GetMergedFlags() | child_1->GetMergedFlags();
+        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);
@@ -15603,6 +15610,8 @@ void ImGui::ShowMetricsWindow(bool* p_open)
                     ImGui::CheckboxFlags("LocalFlags: NoDocking", (ImU32*)&node->LocalFlags, ImGuiDockNodeFlags_NoDocking);
                     ImGui::CheckboxFlags("LocalFlags: NoSplit", (ImU32*)&node->LocalFlags, ImGuiDockNodeFlags_NoSplit);
                     ImGui::CheckboxFlags("LocalFlags: NoResize", (ImU32*)&node->LocalFlags, ImGuiDockNodeFlags_NoResize);
+                    ImGui::CheckboxFlags("LocalFlags: NoResizeX", (ImU32*)&node->LocalFlags, ImGuiDockNodeFlags_NoResizeX);
+                    ImGui::CheckboxFlags("LocalFlags: NoResizeY", (ImU32*)&node->LocalFlags, ImGuiDockNodeFlags_NoResizeY);
                     ImGui::CheckboxFlags("LocalFlags: NoTabBar", (ImU32*)&node->LocalFlags, ImGuiDockNodeFlags_NoTabBar);
                     ImGui::CheckboxFlags("LocalFlags: HiddenTabBar", (ImU32*)&node->LocalFlags, ImGuiDockNodeFlags_HiddenTabBar);
                     ImGui::CheckboxFlags("LocalFlags: NoWindowMenuButton", (ImU32*)&node->LocalFlags, ImGuiDockNodeFlags_NoWindowMenuButton);

imgui.h

@@ -1739,7 +1739,7 @@ struct ImGuiWindowClass
     ImGuiDockNodeFlags  DockNodeFlagsOverrideSet;   // [EXPERIMENTAL] Dock node flags to set when a window of this class is hosted by a dock node (it doesn't have to be selected!)
     ImGuiDockNodeFlags  DockNodeFlagsOverrideClear; // [EXPERIMENTAL]
     bool                DockingAlwaysTabBar;        // Set to true to enforce single floating windows of this class always having their own docking node (equivalent of setting the global io.ConfigDockingAlwaysTabBar)
-    bool                DockingAllowUnclassed;      // Set to true to allow windows of this class to be docked/merged with an unclassed window.
+    bool                DockingAllowUnclassed;      // Set to true to allow windows of this class to be docked/merged with an unclassed window. // FIXME-DOCK: Move to DockNodeFlags override?
 
     ImGuiWindowClass() { ClassId = 0; ParentViewportId = 0; ViewportFlagsOverrideSet = ViewportFlagsOverrideClear = 0x00; DockNodeFlagsOverrideSet = DockNodeFlagsOverrideClear = 0x00; DockingAlwaysTabBar = false; DockingAllowUnclassed = true; }
 };

imgui_internal.h

@@ -1086,10 +1086,17 @@ enum ImGuiDockNodeFlagsPrivate_
     ImGuiDockNodeFlags_NoWindowMenuButton       = 1 << 14,  // Local, Saved  // Disable window/docking menu (that one that appears instead of the collapse button)
     ImGuiDockNodeFlags_NoCloseButton            = 1 << 15,  // Local, Saved  //
     ImGuiDockNodeFlags_NoDocking                = 1 << 16,  // Local, Saved  // Disable any form of docking in this dockspace or individual node. (On a whole dockspace, this pretty much defeat the purpose of using a dockspace at all). Note: when turned on, existing docked nodes will be preserved.
+    ImGuiDockNodeFlags_NoDockingSplitMe         = 1 << 17,  // [EXPERIMENTAL] Prevent another window/node from splitting this node.
+    ImGuiDockNodeFlags_NoDockingSplitOther      = 1 << 18,  // [EXPERIMENTAL] Prevent this node from splitting another window/node.
+    ImGuiDockNodeFlags_NoDockingOverMe          = 1 << 19,  // [EXPERIMENTAL] Prevent another window/node to be docked over this node.
+    ImGuiDockNodeFlags_NoDockingOverOther       = 1 << 20,  // [EXPERIMENTAL] Prevent this node to be docked over another window/node.
+    ImGuiDockNodeFlags_NoResizeX                = 1 << 21,  // [EXPERIMENTAL] 
+    ImGuiDockNodeFlags_NoResizeY                = 1 << 22,  // [EXPERIMENTAL] 
     ImGuiDockNodeFlags_SharedFlagsInheritMask_  = ~0,
-    ImGuiDockNodeFlags_LocalFlagsMask_          = ImGuiDockNodeFlags_NoSplit | ImGuiDockNodeFlags_NoResize | ImGuiDockNodeFlags_AutoHideTabBar | ImGuiDockNodeFlags_DockSpace | ImGuiDockNodeFlags_CentralNode | ImGuiDockNodeFlags_NoTabBar | ImGuiDockNodeFlags_HiddenTabBar | ImGuiDockNodeFlags_NoWindowMenuButton | ImGuiDockNodeFlags_NoCloseButton | ImGuiDockNodeFlags_NoDocking,
+    ImGuiDockNodeFlags_NoResizeFlagsMask_       = ImGuiDockNodeFlags_NoResize | ImGuiDockNodeFlags_NoResizeX | ImGuiDockNodeFlags_NoResizeY,
+    ImGuiDockNodeFlags_LocalFlagsMask_          = ImGuiDockNodeFlags_NoSplit | ImGuiDockNodeFlags_NoResizeFlagsMask_ | ImGuiDockNodeFlags_AutoHideTabBar | ImGuiDockNodeFlags_DockSpace | ImGuiDockNodeFlags_CentralNode | ImGuiDockNodeFlags_NoTabBar | ImGuiDockNodeFlags_HiddenTabBar | ImGuiDockNodeFlags_NoWindowMenuButton | ImGuiDockNodeFlags_NoCloseButton | ImGuiDockNodeFlags_NoDocking,
     ImGuiDockNodeFlags_LocalFlagsTransferMask_  = ImGuiDockNodeFlags_LocalFlagsMask_ & ~ImGuiDockNodeFlags_DockSpace,  // When splitting those flags are moved to the inheriting child, never duplicated
-    ImGuiDockNodeFlags_SavedFlagsMask_          = ImGuiDockNodeFlags_NoResize | ImGuiDockNodeFlags_DockSpace | ImGuiDockNodeFlags_CentralNode | ImGuiDockNodeFlags_NoTabBar | ImGuiDockNodeFlags_HiddenTabBar | ImGuiDockNodeFlags_NoWindowMenuButton | ImGuiDockNodeFlags_NoCloseButton | ImGuiDockNodeFlags_NoDocking
+    ImGuiDockNodeFlags_SavedFlagsMask_          = ImGuiDockNodeFlags_NoResizeFlagsMask_ | ImGuiDockNodeFlags_DockSpace | ImGuiDockNodeFlags_CentralNode | ImGuiDockNodeFlags_NoTabBar | ImGuiDockNodeFlags_HiddenTabBar | ImGuiDockNodeFlags_NoWindowMenuButton | ImGuiDockNodeFlags_NoCloseButton | ImGuiDockNodeFlags_NoDocking
 };
 
 // Store the source authority (dock node vs window) of a field