[graphics] introducing gtk4canvas component

.github/workflows/root-ci-config/buildconfig/global.txt

@@ -71,6 +71,7 @@ pyroot=ON
 pythia8=OFF
 qt6web=OFF
 qt6canv=OFF
+gtk4canv=OFF
 roofit=ON
 root7=ON
 rootbench=OFF

cmake/modules/RootBuildOptions.cmake

@@ -155,6 +155,7 @@ ROOT_BUILD_OPTION(opengl ON "Enable support for OpenGL (requires libGL and libGL
 ROOT_BUILD_OPTION(pyroot ON "Enable support for automatic Python bindings (PyROOT)")
 ROOT_BUILD_OPTION(pythia8 OFF "Enable support for Pythia 8.x [GPL]")
 ROOT_BUILD_OPTION(qt6canv OFF "Enable Qt6 canvas (requires Qt6::Gui)")
+ROOT_BUILD_OPTION(gtk4canv OFF "Enable GTK4 canvas (requires GTK4)")
 ROOT_BUILD_OPTION(qt6web OFF "Enable support for Qt6 web-based display (requires Qt6::WebEngineCore and Qt6::WebEngineWidgets)")
 ROOT_BUILD_OPTION(roofit ON "Build the advanced fitting package RooFit, and RooStats for statistical tests. If xml is available, also build HistFactory.")
 ROOT_BUILD_OPTION(root7 ON "Build ROOT 7 experimental components of ROOT")
@@ -245,6 +246,7 @@ if(all)
  set(pythia8_defvalue ON)
  set(pyroot_defvalue ON)
  set(qt6canv_defvalue ON)
+ set(gtk4canv_defvalue ON)
  set(qt6web_defvalue ON)
  set(r_defvalue ON)
  set(roofit_defvalue ON)

etc/plugins/TCanvasImp/P030_TGtk4Canvas.C

@@ -0,0 +1,5 @@
+void P030_TGtk4Canvas()
+{
+   gPluginMgr->AddHandler("TCanvasImp", "TGtk4Canvas", "ROOT::Experimental::TGtk4Canvas",
+      "ROOTGtk4Canvas", "NewCanvas(TCanvas *, const char *, Int_t, Int_t, UInt_t, UInt_t)");
+}

etc/plugins/TGuiFactory/P030_TGtk4GuiFactory.C

@@ -0,0 +1,5 @@
+void P030_TGtk4GuiFactory()
+{
+   gPluginMgr->AddHandler("TGuiFactory", "gtk4", "ROOT::Experimental::TGtk4GuiFactory",
+      "ROOTGtk4Canvas", "TGtk4GuiFactory()");
+}

etc/plugins/TVirtualPadEditor/P030_TGtk4GedEditor.C

@@ -0,0 +1,5 @@
+void P030_TGtk4GedEditor()
+{
+   gPluginMgr->AddHandler("TVirtualPadEditor", "gtk4", "ROOT::Experimental::TGtk4GedEditor",
+      "ROOTGtk4Canvas", "TGtk4GedEditor(TCanvas*)");
+}

gui/CMakeLists.txt

@@ -16,6 +16,10 @@ if(qt6canv)
   add_subdirectory(qt6canvas)
 endif()
 
+if(gtk4canv)
+  add_subdirectory(gtk4canvas)
+endif()
+
 if(webgui)
    if(cefweb)
       add_subdirectory(cefdisplay)

gui/gtk4canvas/CMakeLists.txt

@@ -0,0 +1,46 @@
+# Copyright (C) 1995-2026, Rene Brun and Fons Rademakers.
+# All rights reserved.
+#
+# For the licensing terms see $ROOTSYS/LICENSE.
+# For the list of contributors see $ROOTSYS/README/CREDITS.
+
+############################################################################
+# CMakeLists.txt file for building ROOT gui/gtk4canvas package
+############################################################################
+
+find_package(PkgConfig)
+
+pkg_check_modules(GTKMM REQUIRED IMPORTED_TARGET gtkmm-4.0)
+
+if(NOT GTKMM_FOUND)
+  if(fail-on-missing)
+    message(FATAL_ERROR "Could NOT find gtkmm-4.0 components")
+  else()
+    message(WARNING "GTKMM not found, disabling option 'gtk4canv'")
+    set(gtk4canv OFF CACHE BOOL "Disabled because GTKMM not found" FORCE)
+    return()
+  endif()
+endif()
+
+
+ROOT_STANDARD_LIBRARY_PACKAGE(ROOTGtk4Canvas
+  HEADERS
+    TGtk4Canvas.h
+    TGtk4GuiFactory.h
+    TGtk4PadPainter.h
+    TGtk4GedEditor.h
+  SOURCES
+    Gtk4DrawArea.cxx
+    Gtk4CanvasWindow.cxx
+    Gtk4MethodDialog.cxx
+    TGtk4ContextMenu.cxx
+    TGtk4Canvas.cxx
+    TGtk4GuiFactory.cxx
+    TGtk4PadPainter.cxx
+    TGtk4GedEditor.cxx
+  LIBRARIES
+    PkgConfig::GTKMM
+  DEPENDENCIES
+    Core
+    Gpad
+)

gui/gtk4canvas/inc/LinkDef.h

@@ -0,0 +1,22 @@
+// Author: Sergey Linev, GSI   12/08/2026
+
+/*************************************************************************
+ * Copyright (C) 1995-2026, Rene Brun and Fons Rademakers.               *
+ * All rights reserved.                                                  *
+ *                                                                       *
+ * For the licensing terms see $ROOTSYS/LICENSE.                         *
+ * For the list of contributors see $ROOTSYS/README/CREDITS.             *
+ *************************************************************************/
+
+#ifdef __CLING__
+
+#pragma link off all globals;
+#pragma link off all classes;
+#pragma link off all functions;
+
+#pragma link C++ class ROOT::Experimental::TGtk4Canvas+;
+#pragma link C++ class ROOT::Experimental::TGtk4PadPainter+;
+#pragma link C++ class ROOT::Experimental::TGtk4GuiFactory+;
+#pragma link C++ class ROOT::Experimental::TGtk4GedEditor+;
+
+#endif

gui/gtk4canvas/inc/TGtk4Canvas.h

@@ -0,0 +1,84 @@
+// Author: Sergey Linev, GSI   12/08/2026
+
+/*************************************************************************
+ * Copyright (C) 1995-2026, Rene Brun and Fons Rademakers.               *
+ * All rights reserved.                                                  *
+ *                                                                       *
+ * For the licensing terms see $ROOTSYS/LICENSE.                         *
+ * For the list of contributors see $ROOTSYS/README/CREDITS.             *
+ *************************************************************************/
+
+#ifndef ROOT_TGtk4Canvas
+#define ROOT_TGtk4Canvas
+
+#include "TCanvasImp.h"
+
+class Gtk4CanvasWindow;
+class Gtk4DrawArea;
+
+namespace ROOT {
+namespace Experimental {
+
+
+class TGtk4Canvas : public TCanvasImp {
+
+protected:
+
+   Gtk4CanvasWindow *fCanvasWindow = nullptr;
+   Gtk4DrawArea *fDrawArea = nullptr;
+
+   Bool_t fFixedSize = kFALSE;      ///<! true when fixed-size canvas is configured
+   UInt_t fClientBits = 0;          ///<! latest status bits from client like editor visible or not
+
+   Bool_t PerformUpdate(Bool_t async) override;
+   TVirtualPadPainter *CreatePadPainter() override;
+
+   void AssignStatusBits(UInt_t bits);
+
+
+public:
+   TGtk4Canvas(TCanvas *c, const char *name, Int_t x, Int_t y, UInt_t width, UInt_t height);
+   ~TGtk4Canvas() override;
+
+   Gtk4DrawArea *GetDrawArea() const { return fDrawArea; }
+
+   Int_t InitWindow() override;
+   void Close() override;
+   void Show() override;
+
+   UInt_t GetWindowGeometry(Int_t &x, Int_t &y, UInt_t &w, UInt_t &h) override;
+   void GetCanvasGeometry(Int_t wid, UInt_t &w, UInt_t &h) override;
+   void ResizeCanvasWindow(Int_t) override {}
+   void UpdateDisplay(Int_t = 0, Bool_t = kFALSE) override {}
+
+   void ShowMenuBar(Bool_t = kTRUE) override { }
+   void ShowStatusBar(Bool_t = kTRUE) override { }
+   void ShowEditor(Bool_t = kTRUE) override {  }
+   void ShowToolBar(Bool_t = kTRUE) override { }
+   void ShowToolTips(Bool_t  = kTRUE) override { }
+
+   void ForceUpdate() override;
+
+   void SetWindowPosition(Int_t x, Int_t y) override;
+   void SetWindowSize(UInt_t w, UInt_t h) override;
+   void SetWindowTitle(const char *newTitle) override;
+   void SetCanvasSize(UInt_t w, UInt_t h) override;
+   void SetCursor(ECursor cursor) override;
+   void Iconify() override;
+   void RaiseWindow() override;
+
+   Bool_t HasEditor() const override;
+   Bool_t HasMenuBar() const override;
+   Bool_t HasStatusBar() const override;
+   Bool_t HasToolBar() const override { return kFALSE; }
+   Bool_t HasToolTips() const override;
+
+   static TCanvasImp *NewCanvas(TCanvas *c, const char *name, Int_t x, Int_t y, UInt_t width, UInt_t height);
+
+   ClassDefOverride(TGtk4Canvas, 0) // Gtk4 implementation for TCanvasImp
+};
+
+} // namespace Experimental
+} // namespace ROOT
+
+#endif

gui/gtk4canvas/inc/TGtk4GedEditor.h

@@ -0,0 +1,105 @@
+// Author: Sergey Linev, GSI   30/10/2026
+
+/*************************************************************************
+ * Copyright (C) 1995-2026, Rene Brun and Fons Rademakers.               *
+ * All rights reserved.                                                  *
+ *                                                                       *
+ * For the licensing terms see $ROOTSYS/LICENSE.                         *
+ * For the list of contributors see $ROOTSYS/README/CREDITS.             *
+ *************************************************************************/
+
+#ifndef ROOT_TGtk4GedEditor
+#define ROOT_TGtk4GedEditor
+
+#include "TVirtualPadEditor.h"
+#include "TQObject.h"
+
+#include <functional>
+
+class TVirtualPad;
+class TAttMarker;
+class TAttText;
+class TAttLine;
+class TAttFill;
+class TClass;
+
+class Gtk4MethodDialog;
+
+namespace Gtk {
+   class DropDown;
+   class SpinButton;
+   class ColorDialogButton;
+}
+
+
+namespace ROOT {
+namespace Experimental {
+
+class TGtk4GedEditor : public TVirtualPadEditor, public TObject, public TQObject {
+
+   protected:
+
+      TCanvas *fCanvas = nullptr;
+      TVirtualPad *fPad = nullptr;
+      TObject *fModel = nullptr;
+      Bool_t fGlobal = kTRUE;
+
+      Gtk4MethodDialog *fDialog = nullptr;
+
+      TAttLine *fAttLine = nullptr;
+      TAttFill *fAttFill = nullptr;
+      TAttText *fAttText = nullptr;
+      TAttMarker *fAttMarker = nullptr;
+
+      Gtk::ColorDialogButton* m_line_color = nullptr;
+      Gtk::DropDown *m_line_style = nullptr;
+      Gtk::SpinButton *m_line_width = nullptr;
+
+      Gtk::ColorDialogButton* m_fill_color = nullptr;
+      Gtk::ColorDialogButton* m_text_color = nullptr;
+      Gtk::ColorDialogButton* m_marker_color = nullptr;
+
+      Int_t GetRootColor(Gtk::ColorDialogButton* btn);
+
+      void FillDialogsElements();
+
+      void ModifiedPad();
+
+      void FillGed(TClass *cl);
+
+      void on_ok_button_clicked();
+
+   public:
+
+      TGtk4GedEditor(TCanvas *c = nullptr);
+      virtual ~TGtk4GedEditor();
+
+      Bool_t   IsGlobal() const override { return fGlobal; }
+      void     SetGlobal(Bool_t on) override { fGlobal = on; }
+
+      TCanvas* GetCanvas() const override { return fCanvas; }
+
+      void ConnectToCanvas(TCanvas *c);
+      void DisconnectFromCanvas();
+      void SetCanvas(TCanvas *c);
+
+      void Show() override;
+      void Hide() override;
+
+      void RecursiveRemove(TObject* obj) override;
+
+      virtual void SetModel(TVirtualPad* pad, TObject* obj, Int_t event);
+
+      // specific editors
+      void AddTAttLine(TAttLine *);
+      void AddTAttFill(TAttFill *);
+      void AddTAttText(TAttText *);
+      void AddTAttMarker(TAttMarker *);
+
+   ClassDefOverride(TGtk4GedEditor, 0) // Implementation for Ged Editor with GTK4
+};
+
+} // namespace Experimental
+} // namespace ROOT
+
+#endif

gui/gtk4canvas/inc/TGtk4GuiFactory.h

@@ -0,0 +1,41 @@
+// Author: Sergey Linev   12/08/2026
+
+/*************************************************************************
+ * Copyright (C) 1995-2026, Rene Brun and Fons Rademakers.               *
+ * All rights reserved.                                                  *
+ *                                                                       *
+ * For the licensing terms see $ROOTSYS/LICENSE.                         *
+ * For the list of contributors see $ROOTSYS/README/CREDITS.             *
+ *************************************************************************/
+
+#ifndef ROOT_TGtk4GuiFactory
+#define ROOT_TGtk4GuiFactory
+
+#include "TGuiFactory.h"
+
+namespace ROOT {
+namespace Experimental {
+
+class TGtk4GuiFactory : public TGuiFactory {
+
+public:
+   TGtk4GuiFactory(const char *name = "gtk4", const char *title = "ROOT Gtk4 GUI Factory");
+   ~TGtk4GuiFactory() override {}
+
+   Bool_t UseVirtualX() const override { return kFALSE; }
+
+   TApplicationImp *CreateApplicationImp(const char *classname, int *argc, char **argv) override;
+
+   TCanvasImp *CreateCanvasImp(TCanvas *c, const char *title, UInt_t width, UInt_t height) override;
+   TCanvasImp *CreateCanvasImp(TCanvas *c, const char *title, Int_t x, Int_t y, UInt_t width, UInt_t height) override;
+
+   TContextMenuImp *CreateContextMenuImp(TContextMenu *c, const char *name, const char *title) override;
+
+   ClassDefOverride(TGtk4GuiFactory,0)  //Factory for Gtk4 GUI components
+};
+
+} //  namespace Experimental
+} // namespace ROOT
+
+
+#endif