Change tracking cue: for instant preview

Strike through deleted previews (expect for inline math where it is already taken care of by RowPainter).

src/insets/InsetPreview.h

@@ -29,7 +29,7 @@ namespace graphics {
 
 /// An inset with an instant preview
 class InsetPreview : public InsetText {
-	
+
 public:
 	///
 	InsetPreview(Buffer *);
@@ -45,11 +45,11 @@ public:
 	Inset * clone() const { return new InsetPreview(*this); }
 
 	bool neverIndent() const { return true; }
-	
+
 	InsetCode lyxCode() const { return PREVIEW_CODE; }
-	
+
 	docstring layoutName() const { return from_ascii("Preview"); }
-	
+
 	bool descendable(BufferView const & /*bv*/) const { return true; }
 
 	std::string contextMenuName() const
@@ -69,8 +69,10 @@ public:
 	void write(std::ostream & os) const;
 
 	void edit(Cursor & cur, bool front, EntryDirection entry_from);
+
+	bool canPaintChange(BufferView const &) const { return true; };
 	//@}
-	
+
 protected:
 	/// Retrieves the preview state. Returns true if preview
 	/// is enabled and the preview image is availabled.

src/insets/RenderPreview.cpp

@@ -193,6 +193,8 @@ void RenderPreview::draw(PainterInfo & pi, int x, int y) const
 			     y - theFontMetrics(font).maxAscent() - 4,
 			     stat, font);
 	}
+	pi.change_.paintCue(pi, x, y - dim_.asc,
+	                    x + dim_.width(), y - dim_.asc + dim_.height());
 }
 
 

src/mathed/InsetMathHull.cpp

@@ -59,11 +59,12 @@
 #include "frontends/Painter.h"
 
 #include "support/convert.h"
-#include "support/lassert.h"
 #include "support/debug.h"
-#include "support/filetools.h"
 #include "support/gettext.h"
+#include "support/filetools.h"
+#include "support/lassert.h"
 #include "support/lstrings.h"
+#include "support/RefChanger.h"
 
 #include <sstream>
 
@@ -567,7 +568,9 @@ void InsetMathHull::draw(PainterInfo & pi, int x, int y) const
 	}
 
 	if (previewState(bv)) {
-		// FIXME CT this
+		// Do not draw change tracking cue if taken care of by RowPainter
+		// already.
+		Changer dummy = make_change(pi.change_, Change(), !canPaintChange(*bv));
 		if (previewTooSmall(dim)) {
 			// we have an extra frame
 			preview_->draw(pi, x + ERROR_FRAME_WIDTH, y);