[LyX/master] Change tracking cue: for instant preview

[Guillaume Munch]

commit 8e1a869c45b0c1cb1ee1f3e85d51325224ec3eb4
Author: Guillaume Munch <g...@lyx.org>
Date:   Mon May 23 15:44:29 2016 +0100

    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    |   12 +++++++-----
 src/insets/RenderPreview.cpp |    2 ++
 src/mathed/InsetMathHull.cpp |    9 ++++++---
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/insets/InsetPreview.h b/src/insets/InsetPreview.h
index d6d693d..f2bfdd5 100644
--- a/src/insets/InsetPreview.h
+++ b/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.
diff --git a/src/insets/RenderPreview.cpp b/src/insets/RenderPreview.cpp
index 59a870c..e985d29 100644
--- a/src/insets/RenderPreview.cpp
+++ b/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());
 }
 
 
diff --git a/src/mathed/InsetMathHull.cpp b/src/mathed/InsetMathHull.cpp
index 2916bb2..88a4c1d 100644
--- a/src/mathed/InsetMathHull.cpp
+++ b/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);