Core: Convert transparency to alpha value for old project files

src/App/PropertyStandard.cpp

@@ -29,6 +29,7 @@
 #include <Base/Console.h>
 #include <Base/Exception.h>
 #include <Base/Interpreter.h>
+#include <Base/ProgramVersion.h>
 #include <Base/Reader.h>
 #include <Base/Writer.h>
 #include <Base/Quantity.h>
@@ -2390,6 +2391,11 @@ void PropertyColor::Restore(Base::XMLReader& reader)
     reader.readElement("PropertyColor");
     // get the value of my Attribute
     unsigned long rgba = reader.getAttributeAsUnsigned("value");
+    if (Base::getVersion(reader.ProgramVersion) < Base::Version::v1_1) {
+        // Convert transparency / alpha value
+        unsigned long alpha = 0xff - (rgba & 0xff);
+        rgba = rgba - (rgba & 0xff) + alpha;
+    }
     setValue(rgba);
 }
 
@@ -2471,6 +2477,8 @@ void PropertyColorList::Restore(Base::XMLReader& reader)
             // initiate a file read
             reader.addFile(file.c_str(), this);
         }
+
+        oldProgramVersion = Base::getVersion(reader.ProgramVersion) < Base::Version::v1_1;
     }
 }
 
@@ -2495,6 +2503,11 @@ void PropertyColorList::RestoreDocFile(Base::Reader& reader)
         str >> value;
         it.setPackedValue(value);
     }
+    if (oldProgramVersion) {
+        for (auto& it : values) {
+            it.a = 1.0F - it.a;
+        }
+    }
     setValues(values);
 }
 
@@ -2725,6 +2738,12 @@ void PropertyMaterial::Restore(Base::XMLReader& reader)
     _cMat.emissiveColor.setPackedValue(reader.getAttributeAsUnsigned("emissiveColor"));
     _cMat.shininess = (float)reader.getAttributeAsFloat("shininess");
     _cMat.transparency = (float)reader.getAttributeAsFloat("transparency");
+    if (Base::getVersion(reader.ProgramVersion) < Base::Version::v1_1) {
+        _cMat.ambientColor.a = 1.0F - _cMat.ambientColor.a;
+        _cMat.diffuseColor.a = 1.0F - _cMat.diffuseColor.a;
+        _cMat.specularColor.a = 1.0F - _cMat.specularColor.a;
+        _cMat.emissiveColor.a = 1.0F - _cMat.emissiveColor.a;
+    }
     if (reader.hasAttribute("image")) {
         _cMat.image = reader.getAttribute("image");
     }
@@ -3270,6 +3289,8 @@ void PropertyMaterialList::Restore(Base::XMLReader& reader)
             // initiate a file read
             reader.addFile(file.c_str(), this);
         }
+
+        oldProgramVersion = Base::getVersion(reader.ProgramVersion) < Base::Version::v1_1;
     }
 }
 
@@ -3353,6 +3374,7 @@ void PropertyMaterialList::RestoreDocFileV0(uint32_t count, Base::Reader& reader
         str >> valueF;
         it.transparency = valueF;
     }
+    convertAlpha(values);
     setValues(values);
 }
 
@@ -3383,9 +3405,22 @@ void PropertyMaterialList::RestoreDocFileV3(Base::Reader& reader)
         readString(str, it.imagePath);
         readString(str, it.uuid);
     }
+    convertAlpha(values);
     setValues(values);
 }
 
+void PropertyMaterialList::convertAlpha(std::vector<App::Material>& materials)
+{
+    if (oldProgramVersion) {
+        for (auto& it : materials) {
+            it.ambientColor.a = 1.0F - it.ambientColor.a;
+            it.diffuseColor.a = 1.0F - it.diffuseColor.a;
+            it.specularColor.a = 1.0F - it.specularColor.a;
+            it.emissiveColor.a = 1.0F - it.emissiveColor.a;
+        }
+    }
+}
+
 void PropertyMaterialList::readString(Base::InputStream& str, std::string& value)
 {
     uint32_t uCt {};

src/App/PropertyStandard.h

@@ -1092,6 +1092,9 @@ class AppExport PropertyColorList: public PropertyListsT<Color>
 
 protected:
     Color getPyValue(PyObject* py) const override;
+
+private:
+    bool oldProgramVersion {false};
 };
 
 
@@ -1295,8 +1298,10 @@ class AppExport PropertyMaterialList: public PropertyListsT<Material>
     void verifyIndex(int index) const;
     void setMinimumSizeOne();
     int resizeByOneIfNeeded(int index);
+    void convertAlpha(std::vector<App::Material>& materials);
 
     Format formatVersion {Version_0};
+    bool oldProgramVersion {false};
 };
 
 

src/Base/ProgramVersion.h

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+/***************************************************************************
+ *   Copyright (c) 2024 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 BASE_PROGRAM_VERSION_H
+#define BASE_PROGRAM_VERSION_H
+
+#include <array>
+#include <map>
+#include <string_view>
+#include <FCGlobal.h>
+
+namespace Base
+{
+
+enum class Version
+{
+    v0_1x,
+    v0_16,
+    v0_17,
+    v0_18,
+    v0_19,
+    v0_20,
+    v0_21,
+    v0_22,
+    v1_0,
+    v1_1,
+    v1_x,
+};
+
+BaseExport Version getVersion(std::string_view str)
+{
+    // clang-format off
+    using VersionItem = std::pair<std::string_view, Version>;
+    static constexpr std::array<VersionItem, 9> items = {{
+        {"0.16", Version::v0_16},
+        {"0.17", Version::v0_17},
+        {"0.18", Version::v0_18},
+        {"0.19", Version::v0_19},
+        {"0.20", Version::v0_20},
+        {"0.21", Version::v0_21},
+        {"0.22", Version::v0_22},
+        {"1.0" , Version::v1_0 },
+        {"1.1" , Version::v1_1 },
+    }};
+    // clang-format on
+    auto it = std::find_if(items.begin(), items.end(), [str](const auto& item) {
+        return str.compare(0, item.first.size(), item.first) == 0;
+    });
+    if (it != items.end()) {
+        return it->second;
+    }
+    if (!str.empty() && str[0] == '0') {
+        return Version::v0_1x;
+    }
+    return Version::v1_x;
+}
+
+}  // namespace Base
+
+#endif  // BASE_PROGRAM_VERSION_H