ViewProvider: add set/getElementColors() API

The API is to expose element color mangement to the core. This patch
provides implementation in Gui::ViewProviderLink and
PartGui::ViewProviderPartExt. ViewProviderLink uses this API to support
color and visibility override functionality, which is required to
implement STEP SHUO (Specified Higher Usage Occurrence) styling.

src/App/DocumentObject.cpp

@@ -958,3 +958,19 @@ std::string DocumentObject::getElementMapVersion(const App::Property *_prop) con
     ss << prop->getComplexData()->getElementMapVersion();
     return ss.str();
 }
+
+const std::string &DocumentObject::hiddenMarker() {
+    static std::string marker("!hide");
+    return marker;
+}
+
+const char *DocumentObject::hasHiddenMarker(const char *subname) {
+    if(!subname) return 0;
+    const char *marker = strrchr(subname,'.');
+    if(!marker)
+        marker = subname;
+    else
+        ++marker;
+    return hiddenMarker()==marker?marker:0;
+}
+

src/App/DocumentObject.h

@@ -419,6 +419,15 @@ class AppExport DocumentObject: public App::TransactionalObject
 
     virtual void onUpdateElementReference(const Property *) {}
 
+    /** Sepecial marker to mark the object has hidden
+     *
+     * It is used by Gui::ViewProvider::getElementColors(), but exposed here
+     * for convenience
+     */
+    static const std::string &hiddenMarker();
+    /// Check if the subname reference ends with hidden marker.
+    static const char *hasHiddenMarker(const char *subname);
+
 protected:
     /// recompute only this object
     virtual App::DocumentObjectExecReturn *recompute(void);

src/App/Link.h

@@ -120,6 +120,10 @@ class AppExport LinkBaseExtension : public App::DocumentObjectExtension
 #define LINK_PARAM_MODE(...) \
     (LinkMode, long, App::PropertyEnumeration, ((long)0), "Link group mode", ##__VA_ARGS__)
 
+#define LINK_PARAM_COLORED_ELEMENTS(...) \
+    (ColoredElements, App::DocumentObject*, App::PropertyLinkSubHidden, \
+     0, "Link colored elements", ##__VA_ARGS__)
+
 #define LINK_PARAM(_param) (LINK_PARAM_##_param())
 
 #define LINK_PNAME(_param) BOOST_PP_TUPLE_ELEM(0,_param)
@@ -145,7 +149,8 @@ class AppExport LinkBaseExtension : public App::DocumentObjectExtension
     LINK_PARAM(COUNT)\
     LINK_PARAM(ELEMENTS)\
     LINK_PARAM(SHOW_ELEMENT)\
-    LINK_PARAM(MODE)
+    LINK_PARAM(MODE)\
+    LINK_PARAM(COLORED_ELEMENTS)
 
     enum PropIndex {
 #define LINK_PINDEX_DEFINE(_1,_2,_param) LINK_PINDEX(_param),
@@ -404,7 +409,8 @@ class AppExport Link : public App::DocumentObject, public App::LinkExtension
     LINK_PARAM_EXT(PLACEMENT)\
     LINK_PARAM_EXT(SUB_ELEMENT)\
     LINK_PARAM_EXT(SHOW_ELEMENT)\
-    LINK_PARAM_EXT_TYPE(COUNT,App::PropertyIntegerConstraint)
+    LINK_PARAM_EXT_TYPE(COUNT,App::PropertyIntegerConstraint)\
+    LINK_PARAM_EXT_ATYPE(COLORED_ELEMENTS,App::Prop_Hidden)
 
     LINK_PROPS_DEFINE(LINK_PARAMS_LINK)
 
@@ -466,7 +472,8 @@ class AppExport LinkGroup : public App::DocumentObject, public App::LinkBaseExte
     LINK_PARAM_EXT(ELEMENTS)\
     LINK_PARAM_EXT(PLACEMENT)\
     LINK_PARAM_EXT(VISIBILITIES)\
-    LINK_PARAM_EXT(MODE)
+    LINK_PARAM_EXT(MODE)\
+    LINK_PARAM_EXT_ATYPE(COLORED_ELEMENTS,App::Prop_Hidden)
 
     // defines the actual properties
     LINK_PROPS_DEFINE(LINK_PARAMS_GROUP)

src/Gui/CMakeLists.txt

@@ -300,6 +300,7 @@ set(Gui_MOC_HDRS
     TaskView/TaskView.h
     DAGView/DAGView.h
     DAGView/DAGModel.h
+    TaskElementColors.h
 )
 
 fc_wrap_cpp(Gui_MOC_SRCS ${Gui_MOC_HDRS})
@@ -370,6 +371,7 @@ SET(Gui_UIC_SRCS
     TextureMapping.ui
     TaskView/TaskAppearance.ui
     TaskView/TaskSelectLinkProperty.ui
+    TaskElementColors.ui
 )
 
 SET(Gui_RES_SRCS
@@ -442,6 +444,7 @@ SET(Dialog_CPP_SRCS
     DownloadItem.cpp
     DownloadManager.cpp
     DocumentRecovery.cpp
+    TaskElementColors.cpp
 )
 
 SET(Dialog_HPP_SRCS
@@ -474,6 +477,7 @@ SET(Dialog_HPP_SRCS
     DownloadItem.h
     DownloadManager.h
     DocumentRecovery.h
+    TaskElementColors.h
 )
 
 SET(Dialog_SRCS
@@ -508,6 +512,7 @@ SET(Dialog_SRCS
     Placement.ui
     SceneInspector.ui
     TextureMapping.ui
+    TaskElementColors.ui
 )
 SOURCE_GROUP("Dialog" FILES ${Dialog_SRCS})