Docking: reinstate io.ConfigDockingWithShift option. (#4643)

This more or less reverts commit 3ed07a8f0b.

docs/CHANGELOG.txt

@@ -99,6 +99,15 @@ Other changes:
   Note that Linux/Mac still have inconsistent support for multi-viewports. If you want to help see https://github.com/ocornut/imgui/issues/2117.
 
 
+-----------------------------------------------------------------------
+ VERSION 1.86 WIP (In Progress)
+-----------------------------------------------------------------------
+
+Docking+Viewports Branch:
+
+- Revert removal of io.ConfigDockingWithShift config option (removed in 1.83). (#4643)
+
+
 -----------------------------------------------------------------------
  VERSION 1.85 (Released 2021-10-12)
 -----------------------------------------------------------------------

imgui.cpp

@@ -1124,6 +1124,7 @@ ImGuiIO::ImGuiIO()
 
     // Docking options (when ImGuiConfigFlags_DockingEnable is set)
     ConfigDockingNoSplit = false;
+    ConfigDockingWithShift = false;
     ConfigDockingAlwaysTabBar = false;
     ConfigDockingTransparentPayload = false;
 
@@ -6836,7 +6837,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         {
             // Docking: Dragging a dockable window (or any of its child) turns it into a drag and drop source.
             // We need to do this _before_ we overwrite window->DC.LastItemId below because BeginDockableDragDropSource() also overwrites it.
-            if (g.MovingWindow == window && g.IO.KeyShift == false)
+            if ((g.MovingWindow == window) && (g.IO.ConfigDockingWithShift == g.IO.KeyShift))
                 if ((window->RootWindowDockTree->Flags & ImGuiWindowFlags_NoDocking) == 0)
                     BeginDockableDragDropSource(window);
 
@@ -14781,9 +14782,9 @@ static void ImGui::DockNodePreviewDockSetup(ImGuiWindow* host_window, ImGuiDockN
             }
         }
 
-    // We only allow and preview docking when hovering over a drop rect or over the title bar
+    // When docking without holding Shift, we only allow and preview docking when hovering over a drop rect or over the title bar
     data->IsDropAllowed = (data->SplitDir != ImGuiDir_None) || (data->IsCenterAvailable);
-    if (!is_explicit_target && !data->IsSplitDirExplicit)
+    if (!is_explicit_target && !data->IsSplitDirExplicit && !g.IO.ConfigDockingWithShift)
         data->IsDropAllowed = false;
 
     // Calculate split area
@@ -16078,7 +16079,7 @@ void ImGui::BeginDockableDragDropSource(ImGuiWindow* window)
     g.LastItemData.ID = window->MoveId;
     window = window->RootWindowDockTree;
     IM_ASSERT((window->Flags & ImGuiWindowFlags_NoDocking) == 0);
-    bool is_drag_docking = ImRect(0, 0, window->SizeFull.x, GetFrameHeight()).Contains(g.ActiveIdClickOffset); // FIXME-DOCKING: Need to make this stateful and explicit
+    bool is_drag_docking = (g.IO.ConfigDockingWithShift) || ImRect(0, 0, window->SizeFull.x, GetFrameHeight()).Contains(g.ActiveIdClickOffset); // FIXME-DOCKING: Need to make this stateful and explicit
     if (is_drag_docking && BeginDragDropSource(ImGuiDragDropFlags_SourceNoPreviewTooltip | ImGuiDragDropFlags_SourceNoHoldToOpenOthers | ImGuiDragDropFlags_SourceAutoExpirePayload))
     {
         SetDragDropPayload(IMGUI_PAYLOAD_TYPE_WINDOW, &window, sizeof(window));
@@ -16139,7 +16140,7 @@ void ImGui::BeginDockableDragDropTarget(ImGuiWindow* window)
         }
 
         const ImRect explicit_target_rect = (node && node->TabBar && !node->IsHiddenTabBar() && !node->IsNoTabBar()) ? node->TabBar->BarRect : ImRect(window->Pos, window->Pos + ImVec2(window->Size.x, GetFrameHeight()));
-        const bool is_explicit_target = IsMouseHoveringRect(explicit_target_rect.Min, explicit_target_rect.Max);
+        const bool is_explicit_target = g.IO.ConfigDockingWithShift || IsMouseHoveringRect(explicit_target_rect.Min, explicit_target_rect.Max);
 
         // Preview docking request and find out split direction/ratio
         //const bool do_preview = true;     // Ignore testing for payload->IsPreview() which removes one frame of delay, but breaks overlapping drop targets within the same window.

imgui.h

@@ -65,7 +65,7 @@ Index of this file:
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
 #define IMGUI_VERSION               "1.85"
-#define IMGUI_VERSION_NUM           18500
+#define IMGUI_VERSION_NUM           18501
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 #define IMGUI_HAS_TABLE
 #define IMGUI_HAS_VIEWPORT          // Viewport WIP branch
@@ -805,8 +805,9 @@ namespace ImGui
     // Docking
     // [BETA API] Enable with io.ConfigFlags |= ImGuiConfigFlags_DockingEnable.
     // Note: You can use most Docking facilities without calling any API. You DO NOT need to call DockSpace() to use Docking!
-    // - Drag from window title bar or their tab to dock/undock. Hold SHIFT to disable docking.
+    // - Drag from window title bar or their tab to dock/undock. Hold SHIFT to disable docking/undocking.
     // - Drag from window menu button (upper-left button) to undock an entire node (all windows).
+    // - When io.ConfigDockingWithShift == true, you instead need to hold SHIFT to _enable_ docking/undocking.
     // About dockspaces:
     // - Use DockSpace() to create an explicit dock node _within_ an existing window. See Docking demo for details.
     // - Use DockSpaceOverViewport() to create an explicit dock node covering the screen or a specific viewport.
@@ -1922,6 +1923,7 @@ struct ImGuiIO
 
     // Docking options (when ImGuiConfigFlags_DockingEnable is set)
     bool        ConfigDockingNoSplit;           // = false          // Simplified docking mode: disable window splitting, so docking is limited to merging multiple windows together into tab-bars.
+    bool        ConfigDockingWithShift;         // = false          // Enable docking with holding Shift key (reduce visual noise, allows dropping in wider space)
     bool        ConfigDockingAlwaysTabBar;      // = false          // [BETA] [FIXME: This currently creates regression with auto-sizing and general overhead] Make every single floating window display within a docking node.
     bool        ConfigDockingTransparentPayload;// = false          // [BETA] Make window or viewport transparent when docking and only display docking boxes on the target viewport. Useful if rendering of multiple viewport cannot be synced. Best used with ConfigViewportsNoAutoMerge.
 

imgui_demo.cpp

@@ -465,12 +465,18 @@ void ImGui::ShowDemoWindow(bool* p_open)
             ImGui::SameLine(); HelpMarker("Instruct backend to not alter mouse cursor shape and visibility.");
 
             ImGui::CheckboxFlags("io.ConfigFlags: DockingEnable", &io.ConfigFlags, ImGuiConfigFlags_DockingEnable);
-            ImGui::SameLine(); HelpMarker("Drag from window title bar or their tab to dock/undock. Hold SHIFT to disable docking.\n\nDrag from window menu button (upper-left button) to undock an entire node (all windows).");
+            ImGui::SameLine();
+            if (io.ConfigDockingWithShift)
+                HelpMarker("Drag from window title bar or their tab to dock/undock. Hold SHIFT to enable docking.\n\nDrag from window menu button (upper-left button) to undock an entire node (all windows).");
+            else
+                HelpMarker("Drag from window title bar or their tab to dock/undock. Hold SHIFT to disable docking.\n\nDrag from window menu button (upper-left button) to undock an entire node (all windows).");
             if (io.ConfigFlags & ImGuiConfigFlags_DockingEnable)
             {
                 ImGui::Indent();
                 ImGui::Checkbox("io.ConfigDockingNoSplit", &io.ConfigDockingNoSplit);
                 ImGui::SameLine(); HelpMarker("Simplified docking mode: disable window splitting, so docking is limited to merging multiple windows together into tab-bars.");
+                ImGui::Checkbox("io.ConfigDockingWithShift", &io.ConfigDockingWithShift);
+                ImGui::SameLine(); HelpMarker("Enable docking when holding Shift only (allow to drop in wider space, reduce visual noise)");
                 ImGui::Checkbox("io.ConfigDockingAlwaysTabBar", &io.ConfigDockingAlwaysTabBar);
                 ImGui::SameLine(); HelpMarker("Create a docking node and tab-bar on single floating windows.");
                 ImGui::Checkbox("io.ConfigDockingTransparentPayload", &io.ConfigDockingTransparentPayload);
@@ -5848,6 +5854,7 @@ void ImGui::ShowAboutWindow(bool* p_open)
         if (io.ConfigViewportsNoDecoration)                             ImGui::Text("io.ConfigViewportsNoDecoration");
         if (io.ConfigViewportsNoDefaultParent)                          ImGui::Text("io.ConfigViewportsNoDefaultParent");
         if (io.ConfigDockingNoSplit)                                    ImGui::Text("io.ConfigDockingNoSplit");
+        if (io.ConfigDockingWithShift)                                  ImGui::Text("io.ConfigDockingWithShift");
         if (io.ConfigDockingAlwaysTabBar)                               ImGui::Text("io.ConfigDockingAlwaysTabBar");
         if (io.ConfigDockingTransparentPayload)                         ImGui::Text("io.ConfigDockingTransparentPayload");
         if (io.ConfigMacOSXBehaviors)                                   ImGui::Text("io.ConfigMacOSXBehaviors");
@@ -7475,6 +7482,7 @@ static void ShowExampleAppCustomRendering(bool* p_open)
 // Note: You can use most Docking facilities without calling any API. You DO NOT need to call DockSpace() to use Docking!
 // - Drag from window title bar or their tab to dock/undock. Hold SHIFT to disable docking.
 // - Drag from window menu button (upper-left button) to undock an entire node (all windows).
+// - When io.ConfigDockingWithShift == true, you instead need to hold SHIFT to _enable_ docking/undocking.
 // About dockspaces:
 // - Use DockSpace() to create an explicit dock node _within_ an existing window.
 // - Use DockSpaceOverViewport() to create an explicit dock node covering the screen or a specific viewport.
@@ -7579,8 +7587,9 @@ void ShowExampleAppDockSpace(bool* p_open)
             "When docking is enabled, you can ALWAYS dock MOST window into another! Try it now!" "\n"
             "- Drag from window title bar or their tab to dock/undock." "\n"
             "- Drag from window menu button (upper-left button) to undock an entire node (all windows)." "\n"
-            "- Hold SHIFT to disable docking." "\n"
-            "This demo app has nothing to do with it!" "\n\n"
+            "- Hold SHIFT to disable docking (if io.ConfigDockingWithShift == false, default)" "\n"
+            "- Hold SHIFT to enable docking (if io.ConfigDockingWithShift == true)" "\n"
+            "This demo app has nothing to do with enabling docking!" "\n\n"
             "This demo app only demonstrate the use of ImGui::DockSpace() which allows you to manually create a docking node _within_ another window." "\n\n"
             "Read comments in ShowExampleAppDockSpace() for more details.");