+ fixes #0000870: Center sketch to a constraint that has been double clicked in the constraint list.

src/Mod/Sketcher/Gui/TaskSketcherConstrains.cpp

@@ -166,6 +166,9 @@ void ConstraintView::contextMenuEvent (QContextMenuEvent* event)
         );
     rename->setEnabled(item != 0);
 
+    QAction* center = menu.addAction(tr("Center sketch"), this, SLOT(centerSelectedItems()));
+    center->setEnabled(item != 0);
+
     QAction* remove = menu.addAction(tr("Delete"), this, SLOT(deleteSelectedItems()),
         QKeySequence(QKeySequence::Delete));
     remove->setEnabled(!items.isEmpty());
@@ -198,6 +201,11 @@ void ConstraintView::renameCurrentItem()
         editItem(item);
 }
 
+void ConstraintView::centerSelectedItems()
+{
+    Q_EMIT emitCenterSelectedItems();
+}
+
 void ConstraintView::deleteSelectedItems()
 {
     App::Document* doc = App::GetApplication().getActiveDocument();
@@ -245,6 +253,10 @@ TaskSketcherConstrains::TaskSketcherConstrains(ViewProviderSketch *sketchView)
         ui->listWidgetConstraints, SIGNAL(itemChanged(QListWidgetItem *)),
         this                     , SLOT  (on_listWidgetConstraints_itemChanged(QListWidgetItem *))
        );
+    QObject::connect(
+        ui->listWidgetConstraints, SIGNAL(emitCenterSelectedItems()),
+        this                     , SLOT  (on_listWidgetConstraints_emitCenterSelectedItems())
+       );
     QObject::connect(
         ui->listWidgetConstraints, SIGNAL(onUpdateDrivingStatus(QListWidgetItem *, bool)),
         this                     , SLOT  (on_listWidgetConstraints_updateDrivingStatus(QListWidgetItem *, bool))
@@ -312,6 +324,11 @@ void TaskSketcherConstrains::on_comboBoxFilter_currentIndexChanged(int)
     slotConstraintsChanged();
 }
 
+void TaskSketcherConstrains::on_listWidgetConstraints_emitCenterSelectedItems()
+{
+    sketchView->centerSelection();
+}
+
 void TaskSketcherConstrains::on_listWidgetConstraints_itemSelectionChanged(void)
 {
     std::string doc_name = sketchView->getSketchObject()->getDocument()->getName();

src/Mod/Sketcher/Gui/TaskSketcherConstrains.h

@@ -51,10 +51,12 @@ protected:
 
 Q_SIGNALS:
     void onUpdateDrivingStatus(QListWidgetItem *item, bool status);
+    void emitCenterSelectedItems();
 
 protected Q_SLOTS:
     void modifyCurrentItem();
     void renameCurrentItem();
+    void centerSelectedItems();
     void deleteSelectedItems();
     void doSelectConstraints();
     void updateDrivingStatus();
@@ -76,10 +78,11 @@ private:
 
 public Q_SLOTS:
     void on_comboBoxFilter_currentIndexChanged(int);
-    void on_listWidgetConstraints_itemSelectionChanged(void); 
+    void on_listWidgetConstraints_itemSelectionChanged(void);
     void on_listWidgetConstraints_itemActivated(QListWidgetItem *item);
     void on_listWidgetConstraints_itemChanged(QListWidgetItem * item);
     void on_listWidgetConstraints_updateDrivingStatus(QListWidgetItem *item, bool status);
+    void on_listWidgetConstraints_emitCenterSelectedItems(void);
 
 protected:
     void changeEvent(QEvent *e);

src/Mod/Sketcher/Gui/ViewProviderSketch.cpp

@@ -1821,6 +1821,40 @@ SbVec3s ViewProviderSketch::getDisplayedSize(const SoImage *iconPtr) const
     return iconSize;
 }
 
+void ViewProviderSketch::centerSelection()
+{
+    Gui::Document* doc = Gui::Application::Instance->getDocument(getObject()->getDocument());
+    Gui::View3DInventor* view = qobject_cast<Gui::View3DInventor*>(doc->getFirstViewOfViewProvider(this));
+    if (!view || !edit)
+        return;
+
+    SoGroup* group = new SoGroup();
+    group->ref();
+
+    for (int i=0; i < edit->constrGroup->getNumChildren(); i++) {
+        if (edit->SelConstraintSet.find(i) != edit->SelConstraintSet.end()) {
+            SoSeparator *sep = dynamic_cast<SoSeparator *>(edit->constrGroup->getChild(i));
+            group->addChild(sep);
+        }
+    }
+
+    Gui::View3DInventorViewer* viewer = view->getViewer();
+    SoGetBoundingBoxAction action(viewer->getSoRenderManager()->getViewportRegion());
+    action.apply(group);
+    group->unref();
+
+    SbBox3f box = action.getBoundingBox();
+    if (!box.isEmpty()) {
+        // get cirumscribing sphere
+        SoCamera* camera = viewer->getSoRenderManager()->getCamera();
+        SbVec3f direction;
+        camera->orientation.getValue().multVec(SbVec3f(0, 0, 1), direction);
+        SbVec3f box_cnt = box.getCenter();
+        SbVec3f cam_pos = box_cnt + camera->focalDistance.getValue() * direction;
+        camera->position.setValue(cam_pos);
+    }
+}
+
 void ViewProviderSketch::doBoxSelection(const SbVec2s &startPos, const SbVec2s &endPos,
                                         const Gui::View3DInventorViewer *viewer)
 {

src/Mod/Sketcher/Gui/ViewProviderSketch.h

@@ -165,6 +165,9 @@ public:
                                            const Gui::View3DInventorViewer *viewer,
                                            const SbVec2s &cursorPos);
 
+    /*! Look at the center of the bounding of all selected items */
+    void centerSelection();
+
     /// box selection method
     void doBoxSelection(const SbVec2s &startPos, const SbVec2s &endPos,
                         const Gui::View3DInventorViewer *viewer);