From c19e1398f260fcd519cb75da4350108cecee0fdb Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Thu, 7 Oct 2021 14:23:46 +0800
Subject: [PATCH 1/9] Import: fix STEP color problem caused by OCC 7.5

Fixes #0004744
---
 src/Mod/Import/App/ExportOCAF.cpp  | 14 +++++++---
 src/Mod/Import/App/ImportOCAF2.cpp | 43 ++++++++++++++++++++----------
 2 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/src/Mod/Import/App/ExportOCAF.cpp b/src/Mod/Import/App/ExportOCAF.cpp
index 2baa95e2f4..bce4ff03b8 100644
--- a/src/Mod/Import/App/ExportOCAF.cpp
+++ b/src/Mod/Import/App/ExportOCAF.cpp
@@ -95,6 +95,12 @@
 #include <App/DocumentObject.h>
 #include <App/DocumentObjectGroup.h>
 
+#if OCC_VERSION_HEX >= 0x070500
+// See https://dev.opencascade.org/content/occt-3d-viewer-becomes-srgb-aware
+#   define OCC_COLOR_SPACE Quantity_TOC_sRGB
+#else
+#   define OCC_COLOR_SPACE Quantity_TOC_RGB
+#endif
 
 using namespace Import;
 
@@ -321,7 +327,7 @@ int ExportOCAF::saveShape(Part::Feature* part, const std::vector<App::Color>& co
                     mat[0] = color.r;
                     mat[1] = color.g;
                     mat[2] = color.b;
-                    col.SetValues(mat[0],mat[1],mat[2],Quantity_TOC_RGB);
+                    col.SetValues(mat[0],mat[1],mat[2],OCC_COLOR_SPACE);
                     aColorTool->SetColor(faceLabel, col, XCAFDoc_ColorSurf);
                 }
             }
@@ -334,7 +340,7 @@ int ExportOCAF::saveShape(Part::Feature* part, const std::vector<App::Color>& co
         mat[0] = color.r;
         mat[1] = color.g;
         mat[2] = color.b;
-        col.SetValues(mat[0],mat[1],mat[2],Quantity_TOC_RGB);
+        col.SetValues(mat[0],mat[1],mat[2],OCC_COLOR_SPACE);
         aColorTool->SetColor(shapeLabel, col, XCAFDoc_ColorGen);
     }
 
@@ -437,7 +443,7 @@ void ExportOCAF::reallocateFreeShape(std::vector <App::DocumentObject*> hierarch
                             mat[0] = color.r;
                             mat[1] = color.g;
                             mat[2] = color.b;
-                            col.SetValues(mat[0],mat[1],mat[2],Quantity_TOC_RGB);
+                            col.SetValues(mat[0],mat[1],mat[2],OCC_COLOR_SPACE);
                             aColorTool->SetColor(faceLabel, col, XCAFDoc_ColorSurf);
                         }
                     }
@@ -451,7 +457,7 @@ void ExportOCAF::reallocateFreeShape(std::vector <App::DocumentObject*> hierarch
                 mat[0] = color.r;
                 mat[1] = color.g;
                 mat[2] = color.b;
-                col.SetValues(mat[0],mat[1],mat[2],Quantity_TOC_RGB);
+                col.SetValues(mat[0],mat[1],mat[2],OCC_COLOR_SPACE);
                 aColorTool->SetColor(label, col, XCAFDoc_ColorGen);
             }
         }
diff --git a/src/Mod/Import/App/ImportOCAF2.cpp b/src/Mod/Import/App/ImportOCAF2.cpp
index 4de3b10adb..d3684e747e 100644
--- a/src/Mod/Import/App/ImportOCAF2.cpp
+++ b/src/Mod/Import/App/ImportOCAF2.cpp
@@ -71,12 +71,31 @@
 #include <App/DocumentObject.h>
 #include <App/DocumentObjectGroup.h>
 
+#if OCC_VERSION_HEX >= 0x070500
+// See https://dev.opencascade.org/content/occt-3d-viewer-becomes-srgb-aware
+#   define OCC_COLOR_SPACE Quantity_TOC_sRGB
+#else
+#   define OCC_COLOR_SPACE Quantity_TOC_RGB
+#endif
+
 FC_LOG_LEVEL_INIT("Import",true,true)
 
 using namespace Import;
 
 /////////////////////////////////////////////////////////////////////
 
+static inline App::Color convertColor(const Quantity_Color &c)
+{
+    Standard_Real r, g, b;
+    c.Values(r, g, b, OCC_COLOR_SPACE);
+    return App::Color(static_cast<float>(r), static_cast<float>(g), static_cast<float>(b));
+}
+
+static inline Quantity_Color convertColor(const App::Color &c)
+{
+    return Quantity_Color(c.r, c.g, c.b, OCC_COLOR_SPACE);
+}
+
 static std::string labelName(TDF_Label label) {
     std::string txt;
     Handle(TDataStd_Name) name;
@@ -229,12 +248,11 @@ void ImportOCAF2::setObjectName(Info &info, TDF_Label label) {
     }
 }
 
-
 bool ImportOCAF2::getColor(const TopoDS_Shape &shape, Info &info, bool check, bool noDefault) {
     bool ret = false;
     Quantity_Color aColor;
     if(aColorTool->GetColor(shape, XCAFDoc_ColorSurf, aColor)) {
-        App::Color c(aColor.Red(),aColor.Green(),aColor.Blue());
+        App::Color c = convertColor(aColor);
         if(!check || info.faceColor!=c) {
             info.faceColor = c;
             info.hasFaceColor = true;
@@ -242,7 +260,7 @@ bool ImportOCAF2::getColor(const TopoDS_Shape &shape, Info &info, bool check, bo
         }
     }
     if(!noDefault && !info.hasFaceColor && aColorTool->GetColor(shape, XCAFDoc_ColorGen, aColor)) {
-        App::Color c(aColor.Red(),aColor.Green(),aColor.Blue());
+        App::Color c = convertColor(aColor);
         if(!check || info.faceColor!=c) {
             info.faceColor = c;
             info.hasFaceColor = true;
@@ -250,7 +268,7 @@ bool ImportOCAF2::getColor(const TopoDS_Shape &shape, Info &info, bool check, bo
         }
     }
     if(aColorTool->GetColor(shape, XCAFDoc_ColorCurv, aColor)) {
-        App::Color c(aColor.Red(),aColor.Green(),aColor.Blue());
+        App::Color c = convertColor(aColor);
         // Some STEP include a curve color with the same value of the face
         // color. And this will look weird in FC. So for shape with face
         // we'll ignore the curve color, if it is the same as the face color.
@@ -369,11 +387,11 @@ bool ImportOCAF2::createObject(App::Document *doc, TDF_Label label,
                 if(aColorTool->GetColor(l, XCAFDoc_ColorSurf, aColor) ||
                    aColorTool->GetColor(l, XCAFDoc_ColorGen, aColor))
                 {
-                    faceColor = App::Color(aColor.Red(),aColor.Green(),aColor.Blue());
+                    faceColor = convertColor(aColor);
                     foundFaceColor = true;
                 }
                 if(aColorTool->GetColor(l, XCAFDoc_ColorCurv, aColor)) {
-                    edgeColor = App::Color(aColor.Red(),aColor.Green(),aColor.Blue());
+                    edgeColor = convertColor(aColor);
                     foundEdgeColor = true;
                     if(j==0 && foundFaceColor && faceColors.size() && edgeColor==faceColor) {
                         // Do not set edge the same color as face
@@ -652,7 +670,7 @@ void ImportOCAF2::getSHUOColors(TDF_Label label,
             if(aColorTool->GetColor(slabel, XCAFDoc_ColorSurf, aColor) ||
                aColorTool->GetColor(slabel, XCAFDoc_ColorGen, aColor))
             {
-                colors.emplace(subname,App::Color(aColor.Red(),aColor.Green(),aColor.Blue()));
+                colors.emplace(subname,convertColor(aColor));
             }
         }
     }
@@ -784,10 +802,7 @@ bool ImportOCAF2::createAssembly(App::Document *_doc,
         childInfo.plas.emplace_back(Part::TopoShape::convert(childShape.Location().Transformation()));
         Quantity_Color aColor;
         if (aColorTool->GetColor(childShape, XCAFDoc_ColorSurf, aColor)) {
-            auto &color = childInfo.colors[childInfo.plas.size()-1];
-            color.r = (float)aColor.Red();
-            color.g = (float)aColor.Green();
-            color.b = (float)aColor.Blue();
+            childInfo.colors[childInfo.plas.size()-1] = convertColor(aColor); 
         }
     }
     assert(visibilities.size() == children.size());
@@ -1036,7 +1051,7 @@ void ExportOCAF2::setupObject(TDF_Label label, App::DocumentObject *obj,
                 continue;
             }
             const App::Color& c = vv.second;
-            Quantity_Color color(c.r,c.g,c.b,Quantity_TOC_RGB);
+            Quantity_Color color = convertColor(c);
             auto colorType = vv.first[0]=='F'?XCAFDoc_ColorSurf:XCAFDoc_ColorCurv;
             if(vv.first=="Face" || vv.first=="Edge") {
                 aColorTool->SetColor(nodeLabel, color, colorType);
@@ -1277,7 +1292,7 @@ TDF_Label ExportOCAF2::exportObject(App::DocumentObject* parentObj,
             // Work around OCCT bug. If no color setting here, it will crash.
             // The culprit is at STEPCAFControl_Writer::1093 as shown below
             //
-            // surfColor = Styles.EncodeColor(Quantity_Color(1,1,1,Quantity_TOC_RGB),DPDCs,ColRGBs);
+            // surfColor = Styles.EncodeColor(Quantity_Color(1,1,1,OCC_COLOR_SPACE),DPDCs,ColRGBs);
             // PSA = Styles.MakeColorPSA ( item, surfColor, curvColor, isComponent );
             // if ( isComponent )
             //     setDefaultInstanceColor( override, PSA);
@@ -1293,7 +1308,7 @@ TDF_Label ExportOCAF2::exportObject(App::DocumentObject* parentObj,
                !aColorTool->GetInstanceColor(childShape,XCAFDoc_ColorCurv,col)) 
             {
                 auto &c = defaultColor;
-                aColorTool->SetColor(childLabel, Quantity_Color(c.r,c.g,c.b,Quantity_TOC_RGB), XCAFDoc_ColorGen);
+                aColorTool->SetColor(childLabel, convertColor(c), XCAFDoc_ColorGen);
                 FC_WARN(labelName(childLabel) << " set default color");
             }
             aColorTool->SetVisibility(childLabel,Standard_False);

From c3e3ff3c8b35bc8763bc460f4683cddc167dbb9f Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Thu, 7 Oct 2021 15:46:14 +0800
Subject: [PATCH 2/9] Part: set transparency in ViewProviderExt::DiffuseColor

For single color shape
---
 src/Mod/Part/Gui/ViewProviderExt.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/Mod/Part/Gui/ViewProviderExt.cpp b/src/Mod/Part/Gui/ViewProviderExt.cpp
index ba197f1811..c43bb64fad 100644
--- a/src/Mod/Part/Gui/ViewProviderExt.cpp
+++ b/src/Mod/Part/Gui/ViewProviderExt.cpp
@@ -443,7 +443,9 @@ void ViewProviderPartExt::onChanged(const App::Property* prop)
     else if (prop == &ShapeMaterial || prop == &ShapeColor) {
         pcFaceBind->value = SoMaterialBinding::OVERALL;
         ViewProviderGeometryObject::onChanged(prop);
-        DiffuseColor.setValue(ShapeColor.getValue());
+        App::Color c = ShapeColor.getValue();
+        c.a = Transparency.getValue()/100.0f;
+        DiffuseColor.setValue(c);
     }
     else if (prop == &Transparency) {
         const App::Material& Mat = ShapeMaterial.getValue();
@@ -795,6 +797,7 @@ std::map<std::string,App::Color> ViewProviderPartExt::getElementColors(const cha
             }
             if(size && singleColor) {
                 color = DiffuseColor[0];
+                color.a = Transparency.getValue()/100.0f;
                 ret.clear();
             }
             ret["Face"] = color;

From b9a76cc8e4e3c89863693ddee3fe1322d21c5433 Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Thu, 7 Oct 2021 15:47:01 +0800
Subject: [PATCH 3/9] Import: support transparency for STEP import and export

---
 src/Mod/Import/App/ImportOCAF2.cpp    | 35 +++++++++++++++------------
 src/Mod/Import/Gui/AppImportGuiPy.cpp |  5 ++--
 2 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/src/Mod/Import/App/ImportOCAF2.cpp b/src/Mod/Import/App/ImportOCAF2.cpp
index d3684e747e..b68f82c0f5 100644
--- a/src/Mod/Import/App/ImportOCAF2.cpp
+++ b/src/Mod/Import/App/ImportOCAF2.cpp
@@ -41,7 +41,7 @@
 # include <TDF_LabelSequence.hxx>
 # include <TDF_ChildIterator.hxx>
 # include <TDataStd_Name.hxx>
-# include <Quantity_Color.hxx>
+# include <Quantity_ColorRGBA.hxx>
 # include <TopoDS_Iterator.hxx>
 # include <Interface_Static.hxx>
 # include <TDF_AttributeSequence.hxx>
@@ -84,16 +84,19 @@ using namespace Import;
 
 /////////////////////////////////////////////////////////////////////
 
-static inline App::Color convertColor(const Quantity_Color &c)
+static inline App::Color convertColor(const Quantity_ColorRGBA &c)
 {
     Standard_Real r, g, b;
-    c.Values(r, g, b, OCC_COLOR_SPACE);
-    return App::Color(static_cast<float>(r), static_cast<float>(g), static_cast<float>(b));
+    c.GetRGB().Values(r, g, b, OCC_COLOR_SPACE);
+    return App::Color(static_cast<float>(r),
+                      static_cast<float>(g),
+                      static_cast<float>(b),
+                      static_cast<float>(c.Alpha()));
 }
 
-static inline Quantity_Color convertColor(const App::Color &c)
+static inline Quantity_ColorRGBA convertColor(const App::Color &c)
 {
-    return Quantity_Color(c.r, c.g, c.b, OCC_COLOR_SPACE);
+    return Quantity_ColorRGBA(Quantity_Color(c.r, c.g, c.b, OCC_COLOR_SPACE), c.a);
 }
 
 static std::string labelName(TDF_Label label) {
@@ -135,13 +138,13 @@ static void printLabel(TDF_Label label, Handle(XCAFDoc_ShapeTool) aShapeTool,
             ss << ", " << Part::TopoShape::shapeName(shape.ShapeType(),true);
     }
     if(aShapeTool->IsShape(label)) {
-        Quantity_Color c;
+        Quantity_ColorRGBA c;
         if(aColorTool->GetColor(label,XCAFDoc_ColorGen,c))
-            ss << ", gc: " << c.StringName(c.Name());
+            ss << ", gc: " << c.ColorToHex(c);
         if(aColorTool->GetColor(label,XCAFDoc_ColorSurf,c))
-            ss << ", sc: " << c.StringName(c.Name());
+            ss << ", sc: " << c.ColorToHex(c);
         if(aColorTool->GetColor(label,XCAFDoc_ColorCurv,c))
-            ss << ", cc: " << c.StringName(c.Name());
+            ss << ", cc: " << c.ColorToHex(c);
     }
 
     ss << std::endl;
@@ -250,7 +253,7 @@ void ImportOCAF2::setObjectName(Info &info, TDF_Label label) {
 
 bool ImportOCAF2::getColor(const TopoDS_Shape &shape, Info &info, bool check, bool noDefault) {
     bool ret = false;
-    Quantity_Color aColor;
+    Quantity_ColorRGBA aColor;
     if(aColorTool->GetColor(shape, XCAFDoc_ColorSurf, aColor)) {
         App::Color c = convertColor(aColor);
         if(!check || info.faceColor!=c) {
@@ -383,7 +386,7 @@ bool ImportOCAF2::createObject(App::Document *doc, TDF_Label label,
 
                 bool foundFaceColor=false,foundEdgeColor=false;
                 App::Color faceColor,edgeColor;
-                Quantity_Color aColor;
+                Quantity_ColorRGBA aColor;
                 if(aColorTool->GetColor(l, XCAFDoc_ColorSurf, aColor) ||
                    aColorTool->GetColor(l, XCAFDoc_ColorGen, aColor))
                 {
@@ -666,7 +669,7 @@ void ImportOCAF2::getSHUOColors(TDF_Label label,
             subname += App::DocumentObject::hiddenMarker();
             colors.emplace(subname,App::Color());
         } else {
-            Quantity_Color aColor;
+            Quantity_ColorRGBA aColor;
             if(aColorTool->GetColor(slabel, XCAFDoc_ColorSurf, aColor) ||
                aColorTool->GetColor(slabel, XCAFDoc_ColorGen, aColor))
             {
@@ -800,7 +803,7 @@ bool ImportOCAF2::createAssembly(App::Document *_doc,
         childInfo.vis.push_back(vis);
         childInfo.labels.push_back(childLabel);
         childInfo.plas.emplace_back(Part::TopoShape::convert(childShape.Location().Transformation()));
-        Quantity_Color aColor;
+        Quantity_ColorRGBA aColor;
         if (aColorTool->GetColor(childShape, XCAFDoc_ColorSurf, aColor)) {
             childInfo.colors[childInfo.plas.size()-1] = convertColor(aColor); 
         }
@@ -1051,7 +1054,7 @@ void ExportOCAF2::setupObject(TDF_Label label, App::DocumentObject *obj,
                 continue;
             }
             const App::Color& c = vv.second;
-            Quantity_Color color = convertColor(c);
+            Quantity_ColorRGBA color = convertColor(c);
             auto colorType = vv.first[0]=='F'?XCAFDoc_ColorSurf:XCAFDoc_ColorCurv;
             if(vv.first=="Face" || vv.first=="Edge") {
                 aColorTool->SetColor(nodeLabel, color, colorType);
@@ -1302,7 +1305,7 @@ TDF_Label ExportOCAF2::exportObject(App::DocumentObject* parentObj,
             //     setDefaultInstanceColor( override, PSA);
             //
             auto childShape = aShapeTool->GetShape(childLabel);
-            Quantity_Color col;
+            Quantity_ColorRGBA col;
             if(!aColorTool->GetInstanceColor(childShape,XCAFDoc_ColorGen,col) &&
                !aColorTool->GetInstanceColor(childShape,XCAFDoc_ColorSurf,col) &&
                !aColorTool->GetInstanceColor(childShape,XCAFDoc_ColorCurv,col)) 
diff --git a/src/Mod/Import/Gui/AppImportGuiPy.cpp b/src/Mod/Import/Gui/AppImportGuiPy.cpp
index 6601973cc2..72e5de3417 100644
--- a/src/Mod/Import/Gui/AppImportGuiPy.cpp
+++ b/src/Mod/Import/Gui/AppImportGuiPy.cpp
@@ -322,9 +322,10 @@ private:
             return;
         }
         // vp->MapFaceColor.setValue(false);
-        if(colors.size() == 1)
+        if(colors.size() == 1) {
             vp->ShapeColor.setValue(colors.front());
-        else 
+            vp->Transparency.setValue(100 * colors.front().a);
+        } else 
             vp->DiffuseColor.setValues(colors);
     }
     virtual void applyEdgeColors(Part::Feature* part, const std::vector<App::Color>& colors) override {

From 329a682a8e42bc4bfd433e92c8e7bc3e41ff20f2 Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Thu, 7 Oct 2021 18:08:00 +0800
Subject: [PATCH 4/9] Import: fix STEP color and add transparency in legacy
 importer/exporter

---
 src/Mod/Import/App/ExportOCAF.cpp | 35 ++++++++++-----------------
 src/Mod/Import/App/ImportOCAF.cpp | 39 +++++++++++++++++++------------
 src/Mod/Import/App/ImportOCAF.h   |  4 ++--
 3 files changed, 38 insertions(+), 40 deletions(-)

diff --git a/src/Mod/Import/App/ExportOCAF.cpp b/src/Mod/Import/App/ExportOCAF.cpp
index bce4ff03b8..9ba1a4d0ae 100644
--- a/src/Mod/Import/App/ExportOCAF.cpp
+++ b/src/Mod/Import/App/ExportOCAF.cpp
@@ -58,7 +58,7 @@
 # include <TDF_LabelSequence.hxx>
 # include <TDF_ChildIterator.hxx>
 # include <TDataStd_Name.hxx>
-# include <Quantity_Color.hxx>
+# include <Quantity_ColorRGBA.hxx>
 # include <STEPCAFControl_Reader.hxx>
 # include <STEPControl_Writer.hxx>
 # include <IGESCAFControl_Reader.hxx>
@@ -102,6 +102,11 @@
 #   define OCC_COLOR_SPACE Quantity_TOC_RGB
 #endif
 
+static inline Quantity_ColorRGBA convertColor(const App::Color &c)
+{
+    return Quantity_ColorRGBA(Quantity_Color(c.r, c.g, c.b, OCC_COLOR_SPACE), c.a);
+}
+
 using namespace Import;
 
 
@@ -290,7 +295,7 @@ int ExportOCAF::saveShape(Part::Feature* part, const std::vector<App::Color>& co
 */
 
     // Add color information
-    Quantity_Color col;
+    Quantity_ColorRGBA col;
 
     std::set<int> face_index;
     TopTools_IndexedMapOfShape faces;
@@ -323,11 +328,7 @@ int ExportOCAF::saveShape(Part::Feature* part, const std::vector<App::Color>& co
 
                 if (!faceLabel.IsNull()) {
                     const App::Color& color = colors[index-1];
-                    Standard_Real mat[3];
-                    mat[0] = color.r;
-                    mat[1] = color.g;
-                    mat[2] = color.b;
-                    col.SetValues(mat[0],mat[1],mat[2],OCC_COLOR_SPACE);
+                    col = convertColor(color);
                     aColorTool->SetColor(faceLabel, col, XCAFDoc_ColorSurf);
                 }
             }
@@ -336,11 +337,7 @@ int ExportOCAF::saveShape(Part::Feature* part, const std::vector<App::Color>& co
     }
     else if (!colors.empty()) {
         App::Color color = colors.front();
-        Standard_Real mat[3];
-        mat[0] = color.r;
-        mat[1] = color.g;
-        mat[2] = color.b;
-        col.SetValues(mat[0],mat[1],mat[2],OCC_COLOR_SPACE);
+        col = convertColor(color);
         aColorTool->SetColor(shapeLabel, col, XCAFDoc_ColorGen);
     }
 
@@ -406,7 +403,7 @@ void ExportOCAF::reallocateFreeShape(std::vector <App::DocumentObject*> hierarch
             TopoDS_Shape baseShape = part->Shape.getValue();
 
             // Add color information
-            Quantity_Color col;
+            Quantity_ColorRGBA col;
 
             std::set<int> face_index;
             TopTools_IndexedMapOfShape faces;
@@ -439,11 +436,7 @@ void ExportOCAF::reallocateFreeShape(std::vector <App::DocumentObject*> hierarch
 
                         if (!faceLabel.IsNull()) {
                             const App::Color& color = colors[index-1];
-                            Standard_Real mat[3];
-                            mat[0] = color.r;
-                            mat[1] = color.g;
-                            mat[2] = color.b;
-                            col.SetValues(mat[0],mat[1],mat[2],OCC_COLOR_SPACE);
+                            col = convertColor(color);
                             aColorTool->SetColor(faceLabel, col, XCAFDoc_ColorSurf);
                         }
                     }
@@ -453,11 +446,7 @@ void ExportOCAF::reallocateFreeShape(std::vector <App::DocumentObject*> hierarch
             }
             else if (!colors.empty()) {
                 App::Color color = colors.front();
-                Standard_Real mat[3];
-                mat[0] = color.r;
-                mat[1] = color.g;
-                mat[2] = color.b;
-                col.SetValues(mat[0],mat[1],mat[2],OCC_COLOR_SPACE);
+                col = convertColor(color);
                 aColorTool->SetColor(label, col, XCAFDoc_ColorGen);
             }
         }
diff --git a/src/Mod/Import/App/ImportOCAF.cpp b/src/Mod/Import/App/ImportOCAF.cpp
index 17cc74f906..f92e7300b3 100644
--- a/src/Mod/Import/App/ImportOCAF.cpp
+++ b/src/Mod/Import/App/ImportOCAF.cpp
@@ -60,7 +60,7 @@
 # include <TDF_LabelSequence.hxx>
 # include <TDF_ChildIterator.hxx>
 # include <TDataStd_Name.hxx>
-# include <Quantity_Color.hxx>
+# include <Quantity_ColorRGBA.hxx>
 # include <STEPCAFControl_Reader.hxx>
 # include <STEPControl_Writer.hxx>
 # include <IGESCAFControl_Reader.hxx>
@@ -108,6 +108,23 @@
 
 using namespace Import;
 
+#if OCC_VERSION_HEX >= 0x070500
+// See https://dev.opencascade.org/content/occt-3d-viewer-becomes-srgb-aware
+#   define OCC_COLOR_SPACE Quantity_TOC_sRGB
+#else
+#   define OCC_COLOR_SPACE Quantity_TOC_RGB
+#endif
+
+static inline App::Color convertColor(const Quantity_ColorRGBA &c)
+{
+    Standard_Real r, g, b;
+    c.GetRGB().Values(r, g, b, OCC_COLOR_SPACE);
+    return App::Color(static_cast<float>(r),
+                      static_cast<float>(g),
+                      static_cast<float>(b),
+                      static_cast<float>(c.Alpha()));
+}
+
 #define OCAF_KEEP_PLACEMENT
 
 ImportOCAF::ImportOCAF(Handle(TDocStd_Document) h, App::Document* d, const std::string& name)
@@ -439,14 +456,12 @@ void ImportOCAF::createShape(const TopoDS_Shape& aShape, const TopLoc_Location&
 
 void ImportOCAF::loadColors(Part::Feature* part, const TopoDS_Shape& aShape)
 {
-    Quantity_Color aColor;
+    Quantity_ColorRGBA aColor;
     App::Color color(0.8f,0.8f,0.8f);
     if (aColorTool->GetColor(aShape, XCAFDoc_ColorGen, aColor) ||
         aColorTool->GetColor(aShape, XCAFDoc_ColorSurf, aColor) ||
         aColorTool->GetColor(aShape, XCAFDoc_ColorCurv, aColor)) {
-        color.r = (float)aColor.Red();
-        color.g = (float)aColor.Green();
-        color.b = (float)aColor.Blue();
+        color = convertColor(aColor);
         std::vector<App::Color> colors;
         colors.push_back(color);
         applyColors(part, colors);
@@ -468,9 +483,7 @@ void ImportOCAF::loadColors(Part::Feature* part, const TopoDS_Shape& aShape)
             aColorTool->GetColor(xp.Current(), XCAFDoc_ColorSurf, aColor) ||
             aColorTool->GetColor(xp.Current(), XCAFDoc_ColorCurv, aColor)) {
             int index = faces.FindIndex(xp.Current());
-            color.r = (float)aColor.Red();
-            color.g = (float)aColor.Green();
-            color.b = (float)aColor.Blue();
+            color = convertColor(aColor);
             faceColors[index-1] = color;
             found_face_color = true;
         }
@@ -551,7 +564,7 @@ void ImportXCAF::createShape(const TopoDS_Shape& shape, bool perface, bool setna
     part = static_cast<Part::Feature*>(doc->addObject("Part::Feature", default_name.c_str()));
     part->Label.setValue(default_name);
     part->Shape.setValue(shape);
-    std::map<Standard_Integer, Quantity_Color>::const_iterator jt;
+    std::map<Standard_Integer, Quantity_ColorRGBA>::const_iterator jt;
     jt = myColorMap.find(shape.HashCode(INT_MAX));
 
     App::Color partColor(0.8f,0.8f,0.8f);
@@ -596,11 +609,7 @@ void ImportXCAF::createShape(const TopoDS_Shape& shape, bool perface, bool setna
             jt = myColorMap.find(xp.Current().HashCode(INT_MAX));
             if (jt != myColorMap.end()) {
                 int index = faces.FindIndex(xp.Current());
-                App::Color color;
-                color.r = (float)jt->second.Red();
-                color.g = (float)jt->second.Green();
-                color.b = (float)jt->second.Blue();
-                faceColors[index-1] = color;
+                faceColors[index-1] = convertColor(jt->second);
                 found_face_color = true;
             }
             xp.Next();
@@ -653,7 +662,7 @@ void ImportXCAF::loadShapes(const TDF_Label& label)
         }
 
         // getting color
-        Quantity_Color col;
+        Quantity_ColorRGBA col;
         if (hColors->GetColor(label, XCAFDoc_ColorGen, col) ||
             hColors->GetColor(label, XCAFDoc_ColorSurf, col) ||
             hColors->GetColor(label, XCAFDoc_ColorCurv, col)) {
diff --git a/src/Mod/Import/App/ImportOCAF.h b/src/Mod/Import/App/ImportOCAF.h
index 8c4d609265..4f30d921a9 100644
--- a/src/Mod/Import/App/ImportOCAF.h
+++ b/src/Mod/Import/App/ImportOCAF.h
@@ -27,7 +27,7 @@
 #include <TDocStd_Document.hxx>
 #include <XCAFDoc_ColorTool.hxx>
 #include <XCAFDoc_ShapeTool.hxx>
-#include <Quantity_Color.hxx>
+#include <Quantity_ColorRGBA.hxx>
 #include <TopoDS_Shape.hxx>
 #include <TDF_LabelMapHasher.hxx>
 #include <climits>
@@ -117,7 +117,7 @@ private:
     std::map<Standard_Integer, TopoDS_Shape> myShells;
     std::map<Standard_Integer, TopoDS_Shape> myCompds;
     std::map<Standard_Integer, TopoDS_Shape> myShapes;
-    std::map<Standard_Integer, Quantity_Color> myColorMap;
+    std::map<Standard_Integer, Quantity_ColorRGBA> myColorMap;
     std::map<Standard_Integer, std::string> myNameMap;
 };
 

From 709181d9091ff7ee22153576c0af994ec8e74a6e Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Fri, 8 Oct 2021 07:51:00 +0800
Subject: [PATCH 5/9] Import: avoid using Quantity_ColorRGBA::ColorToHex()

For using older OCCT
---
 src/Mod/Import/App/ImportOCAF2.cpp | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/Mod/Import/App/ImportOCAF2.cpp b/src/Mod/Import/App/ImportOCAF2.cpp
index b68f82c0f5..f997187f36 100644
--- a/src/Mod/Import/App/ImportOCAF2.cpp
+++ b/src/Mod/Import/App/ImportOCAF2.cpp
@@ -50,6 +50,7 @@
 
 #include <XCAFDoc_ShapeMapTool.hxx>
 
+#include <boost/format.hpp>
 #include <boost/regex.hpp>
 #include <boost/algorithm/string.hpp>
 #include <Base/Parameter.h>
@@ -99,6 +100,12 @@ static inline Quantity_ColorRGBA convertColor(const App::Color &c)
     return Quantity_ColorRGBA(Quantity_Color(c.r, c.g, c.b, OCC_COLOR_SPACE), c.a);
 }
 
+static inline std::ostream& operator<<(std::ostream& os, const Quantity_ColorRGBA &c) {
+    App::Color color = convertColor(c);
+    auto toHex = [](float v) {return boost::format("%02X") % static_cast<int>(v*255);};
+    return os << "#" << toHex(color.r) << toHex(color.g) << toHex(color.b) << toHex(color.a);
+}
+
 static std::string labelName(TDF_Label label) {
     std::string txt;
     Handle(TDataStd_Name) name;
@@ -140,11 +147,11 @@ static void printLabel(TDF_Label label, Handle(XCAFDoc_ShapeTool) aShapeTool,
     if(aShapeTool->IsShape(label)) {
         Quantity_ColorRGBA c;
         if(aColorTool->GetColor(label,XCAFDoc_ColorGen,c))
-            ss << ", gc: " << c.ColorToHex(c);
+            ss << ", gc: " << c;
         if(aColorTool->GetColor(label,XCAFDoc_ColorSurf,c))
-            ss << ", sc: " << c.ColorToHex(c);
+            ss << ", sc: " << c;
         if(aColorTool->GetColor(label,XCAFDoc_ColorCurv,c))
-            ss << ", cc: " << c.ColorToHex(c);
+            ss << ", cc: " << c;
     }
 
     ss << std::endl;

From beea1d364477424e4f24d9411f9ba36f61f849af Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Sat, 9 Oct 2021 15:53:51 +0800
Subject: [PATCH 6/9] Import: fix single shape STEP export with per face color

---
 src/Mod/Import/App/ImportOCAF2.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/Mod/Import/App/ImportOCAF2.cpp b/src/Mod/Import/App/ImportOCAF2.cpp
index f997187f36..3b0d6ea49a 100644
--- a/src/Mod/Import/App/ImportOCAF2.cpp
+++ b/src/Mod/Import/App/ImportOCAF2.cpp
@@ -1244,8 +1244,17 @@ TDF_Label ExportOCAF2::exportObject(App::DocumentObject* parentObj,
             // not call setupObject() on a non-located baseshape like above,
             // because OCCT does not respect shape style sharing when not
             // exporting assembly
-            if(!keepPlacement) 
+            if(!keepPlacement || shape.getPlacement() == Base::Placement())
                 shape.setShape(shape.getShape().Located(TopLoc_Location()));
+            else {
+                Base::Matrix4D mat = shape.getTransform();
+                shape.setShape(shape.getShape().Located(TopLoc_Location()));
+                // Transform with copy to conceal the transformation
+                shape.transformShape(mat, true);
+                // Even if the shape has no transformation, TopoShape still sets
+                // a TopLoc_Location, so we need to clear it again.
+                shape.setShape(shape.getShape().Located(TopLoc_Location()));
+            }
             label = aShapeTool->AddShape(shape.getShape(),Standard_False, Standard_False);
             auto o = name?parentObj:obj;
             if(o!=linked)

From c01878c174ad7548996a4ec78f67d96bf3836263 Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Sat, 9 Oct 2021 20:43:24 +0800
Subject: [PATCH 7/9] Import: fix transparency STEP export/import

App::Color::a in FreeCAD is actually interpreted as transparency
instead of alpha.
---
 src/Mod/Import/App/ExportOCAF.cpp  | 2 +-
 src/Mod/Import/App/ImportOCAF.cpp  | 2 +-
 src/Mod/Import/App/ImportOCAF2.cpp | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Mod/Import/App/ExportOCAF.cpp b/src/Mod/Import/App/ExportOCAF.cpp
index 9ba1a4d0ae..3a76769b42 100644
--- a/src/Mod/Import/App/ExportOCAF.cpp
+++ b/src/Mod/Import/App/ExportOCAF.cpp
@@ -104,7 +104,7 @@
 
 static inline Quantity_ColorRGBA convertColor(const App::Color &c)
 {
-    return Quantity_ColorRGBA(Quantity_Color(c.r, c.g, c.b, OCC_COLOR_SPACE), c.a);
+    return Quantity_ColorRGBA(Quantity_Color(c.r, c.g, c.b, OCC_COLOR_SPACE), 1.0 - c.a);
 }
 
 using namespace Import;
diff --git a/src/Mod/Import/App/ImportOCAF.cpp b/src/Mod/Import/App/ImportOCAF.cpp
index f92e7300b3..a6c392f0b7 100644
--- a/src/Mod/Import/App/ImportOCAF.cpp
+++ b/src/Mod/Import/App/ImportOCAF.cpp
@@ -122,7 +122,7 @@ static inline App::Color convertColor(const Quantity_ColorRGBA &c)
     return App::Color(static_cast<float>(r),
                       static_cast<float>(g),
                       static_cast<float>(b),
-                      static_cast<float>(c.Alpha()));
+                      1.0f - static_cast<float>(c.Alpha()));
 }
 
 #define OCAF_KEEP_PLACEMENT
diff --git a/src/Mod/Import/App/ImportOCAF2.cpp b/src/Mod/Import/App/ImportOCAF2.cpp
index 3b0d6ea49a..1c803be05c 100644
--- a/src/Mod/Import/App/ImportOCAF2.cpp
+++ b/src/Mod/Import/App/ImportOCAF2.cpp
@@ -92,12 +92,12 @@ static inline App::Color convertColor(const Quantity_ColorRGBA &c)
     return App::Color(static_cast<float>(r),
                       static_cast<float>(g),
                       static_cast<float>(b),
-                      static_cast<float>(c.Alpha()));
+                      1.0f - static_cast<float>(c.Alpha()));
 }
 
 static inline Quantity_ColorRGBA convertColor(const App::Color &c)
 {
-    return Quantity_ColorRGBA(Quantity_Color(c.r, c.g, c.b, OCC_COLOR_SPACE), c.a);
+    return Quantity_ColorRGBA(Quantity_Color(c.r, c.g, c.b, OCC_COLOR_SPACE), 1.0f - c.a);
 }
 
 static inline std::ostream& operator<<(std::ostream& os, const Quantity_ColorRGBA &c) {

From 498b40800e308e895fbb0e783d2558c79da68512 Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Sun, 10 Oct 2021 22:01:25 +0800
Subject: [PATCH 8/9] Part: sync ViewProviderExt::DiffuseColor on Transparency
 change

---
 src/Mod/Part/Gui/ViewProviderExt.cpp | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/src/Mod/Part/Gui/ViewProviderExt.cpp b/src/Mod/Part/Gui/ViewProviderExt.cpp
index c43bb64fad..47257f6958 100644
--- a/src/Mod/Part/Gui/ViewProviderExt.cpp
+++ b/src/Mod/Part/Gui/ViewProviderExt.cpp
@@ -452,17 +452,10 @@ void ViewProviderPartExt::onChanged(const App::Property* prop)
         long value = (long)(100*Mat.transparency);
         if (value != Transparency.getValue()) {
             float trans = Transparency.getValue()/100.0f;
-            if (pcFaceBind->value.getValue() == SoMaterialBinding::PER_PART) {
-                int cnt = pcShapeMaterial->diffuseColor.getNum();
-                pcShapeMaterial->transparency.setNum(cnt);
-                float *t = pcShapeMaterial->transparency.startEditing();
-                for (int i=0; i<cnt; i++)
-                    t[i] = trans;
-                pcShapeMaterial->transparency.finishEditing();
-            }
-            else {
-                pcShapeMaterial->transparency = trans;
-            }
+            auto colors = DiffuseColor.getValues();
+            for (auto &c : colors)
+                c.a = Transparency.getValue()/100.0f;
+            DiffuseColor.setValues(colors);
 
             App::PropertyContainer* parent = ShapeMaterial.getContainer();
             ShapeMaterial.setContainer(0);
@@ -731,7 +724,7 @@ void ViewProviderPartExt::setHighlightedFaces(const std::vector<App::Color>& col
     else if (colors.size() == 1) {
         pcFaceBind->value = SoMaterialBinding::OVERALL;
         pcShapeMaterial->diffuseColor.setValue(colors[0].r, colors[0].g, colors[0].b);
-        //pcShapeMaterial->transparency = colors[0].a; do not get transparency from DiffuseColor in this case
+        pcShapeMaterial->transparency = Transparency.getValue()/100.f;
     }
 }
 

From 45d06607277dcebe7e6edbcc88ad0a2ee3ff6c1d Mon Sep 17 00:00:00 2001
From: "Zheng, Lei" <realthunder.dev@gmail.com>
Date: Mon, 11 Oct 2021 06:02:54 +0800
Subject: [PATCH 9/9] Part: minor change on transparency setting

---
 src/Mod/Part/Gui/ViewProviderExt.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Mod/Part/Gui/ViewProviderExt.cpp b/src/Mod/Part/Gui/ViewProviderExt.cpp
index 47257f6958..dd0cf77a53 100644
--- a/src/Mod/Part/Gui/ViewProviderExt.cpp
+++ b/src/Mod/Part/Gui/ViewProviderExt.cpp
@@ -454,7 +454,7 @@ void ViewProviderPartExt::onChanged(const App::Property* prop)
             float trans = Transparency.getValue()/100.0f;
             auto colors = DiffuseColor.getValues();
             for (auto &c : colors)
-                c.a = Transparency.getValue()/100.0f;
+                c.a = trans;
             DiffuseColor.setValues(colors);
 
             App::PropertyContainer* parent = ShapeMaterial.getContainer();