fixes #9134: Points Merge doesn't keep Color information

src/Mod/Points/App/CMakeLists.txt

@@ -48,6 +48,7 @@ SET(Points_SRCS
     PropertyPointKernel.h
     Structured.cpp
     Structured.h
+    Tools.h
 )
 
 set(Points_Scripts

src/Mod/Points/App/Tools.h

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+/***************************************************************************
+ *   Copyright (c) 2023 Werner Mayer <wmayer[at]users.sourceforge.net>     *
+ *                                                                         *
+ *   This file is part of FreeCAD.                                         *
+ *                                                                         *
+ *   FreeCAD is free software: you can redistribute it and/or modify it    *
+ *   under the terms of the GNU Lesser General Public License as           *
+ *   published by the Free Software Foundation, either version 2.1 of the  *
+ *   License, or (at your option) any later version.                       *
+ *                                                                         *
+ *   FreeCAD is distributed in the hope that it will be useful, but        *
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
+ *   Lesser General Public License for more details.                       *
+ *                                                                         *
+ *   You should have received a copy of the GNU Lesser General Public      *
+ *   License along with FreeCAD. If not, see                               *
+ *   <https://www.gnu.org/licenses/>.                                      *
+ *                                                                         *
+ **************************************************************************/
+
+#ifndef POINTS_TOOLS_H
+#define POINTS_TOOLS_H
+
+#include <algorithm>
+#include <App/DocumentObject.h>
+
+namespace Points {
+
+template<typename PropertyT>
+bool copyProperty(App::DocumentObject* target,
+                  std::vector<App::DocumentObject*> source,
+                  const char* propertyName)
+{
+    // check for properties
+    if (std::all_of(std::begin(source), std::end(source), [=](auto obj) {
+            return dynamic_cast<PropertyT*>(obj->getPropertyByName(propertyName)) != nullptr;
+        })) {
+
+        auto target_prop = dynamic_cast<PropertyT*>
+            (target->addDynamicProperty(PropertyT::getClassTypeId().getName(), propertyName));
+        if (target_prop) {
+            auto values = target_prop->getValues();
+            for (auto it : source) {
+                auto source_prop = dynamic_cast<PropertyT*>
+                    (it->getPropertyByName(propertyName));
+                if (source_prop) {
+                    auto source_values = source_prop->getValues();
+                    values.insert(values.end(), source_values.begin(), source_values.end());
+                }
+            }
+
+            target_prop->setValues(values);
+            return true;
+        }
+    }
+
+    return false;
+}
+
+}
+
+#endif // POINTS_TOOLS_H

src/Mod/Points/Gui/Command.cpp

@@ -41,11 +41,13 @@
 #include <Gui/Selection.h>
 #include <Gui/View3DInventor.h>
 #include <Gui/View3DInventorViewer.h>
+#include <Gui/ViewProviderDocumentObject.h>
 #include <Gui/WaitCursor.h>
 
 #include "../App/PointsFeature.h"
 #include "../App/Structured.h"
 #include "../App/Properties.h"
+#include "../App/Tools.h"
 
 #include "DlgPointsReadImp.h"
 #include "ViewProvider.h"
@@ -323,8 +325,8 @@ void CmdPointsMerge::activated(int iMsg)
     Points::PointKernel* kernel = pts->Points.startEditing();
 
     std::vector<App::DocumentObject*> docObj = Gui::Selection().getObjectsOfType(Points::Feature::getClassTypeId());
-    for (std::vector<App::DocumentObject*>::iterator it = docObj.begin(); it != docObj.end(); ++it) {
-        const Points::PointKernel& k = static_cast<Points::Feature*>(*it)->Points.getValue();
+    for (auto it : docObj) {
+        const Points::PointKernel& k = static_cast<Points::Feature*>(it)->Points.getValue();
         std::size_t numPts = kernel->size();
         kernel->resize(numPts + k.size());
         for (std::size_t i=0; i<k.size(); ++i) {
@@ -333,6 +335,24 @@ void CmdPointsMerge::activated(int iMsg)
     }
 
     pts->Points.finishEditing();
+
+    // Add properties
+    std::string displayMode = "Points";
+    if (Points::copyProperty<App::PropertyColorList>(pts, docObj, "Color")) {
+        displayMode = "Color";
+    }
+    if (Points::copyProperty<Points::PropertyNormalList>(pts, docObj, "Normal")) {
+        displayMode = "Shaded";
+    }
+    if (Points::copyProperty<Points::PropertyGreyValueList>(pts, docObj, "Intensity")) {
+        displayMode = "Intensity";
+    }
+
+    if (auto vp = dynamic_cast<Gui::ViewProviderDocumentObject*>
+            (Gui::Application::Instance->getViewProvider(pts))) {
+        vp->DisplayMode.setValue(displayMode.c_str());
+    }
+
     doc->commitTransaction();
     updateActive();
 }