Enable graphics-unify only for selections containing graphics insets.

Follow-up of
https://www.mail-archive.com/lyx-devel@lists.lyx.org/msg204907.html

src/BufferView.cpp

@@ -1154,7 +1154,7 @@ bool BufferView::getStatus(FuncRequest const & cmd, FuncStatus & flag)
 		break;
 
 	case LFUN_GRAPHICS_UNIFY:
-		flag.setEnabled(cur.selection());
+		flag.setEnabled(cur.countInsetsInSelection(GRAPHICS_CODE)>1);
 		break;
 
 	case LFUN_WORD_FINDADV: {

src/Cursor.cpp

@@ -496,6 +496,56 @@ void CursorData::clearSelection()
 }
 
 
+int CursorData::countInsetsInSelection(InsetCode const & inset_code)
+{
+	if (!selection_)
+		return 0;
+
+	DocIterator from, to;
+	from = selectionBegin();
+	to = selectionEnd();
+
+	int count = 0;
+
+	if (!from.nextInset())      //move to closest inset
+		from.forwardInset();
+
+	while (!from.empty() && from < to) {
+		Inset * inset = from.nextInset();
+		if (!inset)
+			break;
+		if (inset->lyxCode() == inset_code)
+			count ++;
+		from.forwardInset();
+	}
+	return count;
+}
+
+
+bool CursorData::insetInSelection(InsetCode const & inset_code)
+{
+	if (!selection_)
+		return false;
+
+	DocIterator from, to;
+	from = selectionBegin();
+	to = selectionEnd();
+
+	if (!from.nextInset())      //move to closest inset
+		from.forwardInset();
+
+	while (!from.empty() && from < to) {
+		Inset * inset = from.nextInset();
+		if (!inset)
+			break;
+		if (inset->lyxCode() == inset_code)
+			return true;
+		from.forwardInset();
+	}
+	return false;
+}
+
+
 bool CursorData::fixIfBroken()
 {
 	bool const broken_cursor = DocIterator::fixIfBroken();

src/Cursor.h

@@ -129,6 +129,12 @@ public:
 	void setSelection(DocIterator const & where, int n);
 	///
 	void clearSelection();
+	/// check whether selection contains specific type of inset
+	/// returns 0 if no selection was made
+	bool insetInSelection(InsetCode const & inset);
+	/// count occurences of specific inset type in the selection
+	/// returns 0 if no selection was made
+	int countInsetsInSelection(InsetCode const & inset);
 
 	/// access to normalized selection anchor
 	CursorSlice normalAnchor() const;