Fix caret painting

The trick is to remember in BufferView what has been done at the
previous draw, so that the row that contained the caret can be
repainted if needed.

To this end, add an argument paint_caret to BufferView, although
painting the caret is not the job of the BufferView (at this point).

BufferView::needRepaint will act as an interface with
TextMetrics::drawParagraph to know whether the painting of a given
row should be forced.

Currently everything is done at the top row level, so that, if the
caret is in a large table, the whole table will have to be repainted.
It is not clear yet that this is necessary.

diff --git a/src/BufferView.cpp b/src/BufferView.cpp
index 00de06080ad75e4a4e76d83b5b1fa95558627b54..4b78006f63b4ff360a2675a9c4f0e5f178dea0b8 100644 (file)
--- a/src/BufferView.cpp
+++ b/src/BufferView.cpp
@@ -235,7 +235,7 @@ struct BufferView::Private
                last_inset_(0), clickable_inset_(false),
                mouse_position_cache_(),
                bookmark_edit_position_(-1), gui_(0),
-               horiz_scroll_offset_(0)
+               horiz_scroll_offset_(0), repaint_caret_row_(false)
        {
                xsel_cache_.set = false;
        }
@@ -312,6 +312,12 @@ struct BufferView::Private
        /// a slice pointing to the start of the row where cursor was
        /// at previous draw event
        CursorSlice last_row_slice_;
+
+       /// a slice pointing to where the cursor has been drawn after the current
+       /// draw() call.
+       CursorSlice caret_slice_;
+       /// indicates whether the caret slice needs to be repainted in this draw() run.
+       bool repaint_caret_row_;
 };
 
 
@@ -2761,7 +2767,7 @@ void BufferView::updatePosCache()
        // this is the "nodraw" drawing stage: only set the positions of the
        // insets in metrics cache.
        frontend::NullPainter np;
-       draw(np);
+       draw(np, false);
 }
 
 
@@ -2972,6 +2978,23 @@ void BufferView::setCurrentRowSlice(CursorSlice const & rowSlice)
 }
 
 
+namespace {
+
+bool sliceInRow(CursorSlice const & cs, Text const * text, Row const & row)
+{
+       return !cs.empty() && cs.text() == text && cs.pit() == row.pit()
+               && row.pos() <= cs.pos() && cs.pos() <= row.endpos();
+}
+
+}
+
+
+bool BufferView::needRepaint(Text const * text, Row const & row) const
+{
+       return d->repaint_caret_row_ && sliceInRow(d->caret_slice_, text, row);
+}
+
+
 void BufferView::checkCursorScrollOffset(PainterInfo & pi)
 {
        CursorSlice rowSlice = d->cursor_.bottom();
@@ -3060,7 +3083,7 @@ void BufferView::checkCursorScrollOffset(PainterInfo & pi)
 }
 
 
-void BufferView::draw(frontend::Painter & pain)
+void BufferView::draw(frontend::Painter & pain, bool paint_caret)
 {
        if (height_ == 0 || width_ == 0)
                return;
@@ -3071,6 +3094,16 @@ void BufferView::draw(frontend::Painter & pain)
        int const y = tm.first().second->position();
        PainterInfo pi(this, pain);
 
+       CursorSlice const & bottomSlice = d->cursor_.bottom();
+       /**  A repaint of the previous cursor row is needed if
+        * 1/ the caret will be painted and is is not the same than the
+        *    already painted one;
+        * 2/ the caret will not be painted, but there is already one on
+        * screen.
+        */
+       d->repaint_caret_row_ = (paint_caret && bottomSlice != d->caret_slice_)
+               || (! paint_caret && !d->caret_slice_.empty());
+
        // Check whether the row where the cursor lives needs to be scrolled.
        // Update the drawing strategy if needed.
        checkCursorScrollOffset(pi);
@@ -3082,9 +3115,14 @@ void BufferView::draw(frontend::Painter & pain)
                // however, the different coordinates of insets and paragraphs
                // needs to be updated.
                LYXERR(Debug::PAINTING, "Strategy: NoScreenUpdate");
-               pi.full_repaint = true;
-               if (pain.isNull())
+               pi.full_repaint = false;
+               if (pain.isNull()) {
+                       pi.full_repaint = true;
+                       tm.draw(pi, 0, y);
+               } else if (d->repaint_caret_row_) {
+                       pi.full_repaint = false;
                        tm.draw(pi, 0, y);
+               }
                break;
 
        case SingleParUpdate:
@@ -3147,6 +3185,12 @@ void BufferView::draw(frontend::Painter & pain)
        }
        LYXERR(Debug::PAINTING, "Found new anchor pit = " << d->anchor_pit_
                << "  anchor ypos = " << d->anchor_ypos_);
+
+       // Remember what has just been done for the next draw() step
+       if (paint_caret)
+               d->caret_slice_ = bottomSlice;
+       else
+               d->caret_slice_ = CursorSlice();
 }
 
 

diff --git a/src/BufferView.h b/src/BufferView.h
index 83b4d39e3771aa0ab41142df4c7ca0f325182616..c0f0b9006388b511e883d4196d17052598a807bc 100644 (file)
--- a/src/BufferView.h
+++ b/src/BufferView.h
@@ -46,6 +46,7 @@ class PainterInfo;
 class ParIterator;
 class ParagraphMetrics;
 class Point;
+class Row;
 class TexRow;
 class Text;
 class TextMetrics;
@@ -132,6 +133,9 @@ public:
        /// Only to be called with good y coordinates (after a bv::metrics)
        bool needsFitCursor() const;
 
+       /// returns true if this row needs to be repainted (to erase caret)
+       bool needRepaint(Text const * text, Row const & row) const;
+
        // Returns the amount of horizontal scrolling applied to the
        // top-level row where the cursor lies
        int horizScrollOffset() const;
@@ -308,7 +312,7 @@ public:
        void cursorPosAndHeight(Point & p, int & h) const;
 
        ///
-       void draw(frontend::Painter & pain);
+       void draw(frontend::Painter & pain, bool paint_caret);
 
        /// get this view's keyboard map handler.
        Intl & getIntl();

diff --git a/src/MetricsInfo.h b/src/MetricsInfo.h
index 2a18cf8cffdc11fbc47b9363a2549955e2cdfd8a..ff0b1c698941faeec9e2add2b2f2f3dc408c4f93 100644 (file)
--- a/src/MetricsInfo.h
+++ b/src/MetricsInfo.h
@@ -130,7 +130,7 @@ public:
        bool selected;
        /// Whether the spell checker is enabled for the parent
        bool do_spellcheck;
-       ///
+       /// True when it can be assumed that the screen has been cleared
        bool full_repaint;
        /// Current background color
        ColorCode background_color;

diff --git a/src/TextMetrics.cpp b/src/TextMetrics.cpp
index c5784070d26cc8692735b45318802cb7fef60cd8..c6f6bbf62c7c126c0a4849b98d9de15ae48cf96c 100644 (file)
--- a/src/TextMetrics.cpp
+++ b/src/TextMetrics.cpp
@@ -1881,7 +1881,8 @@ void TextMetrics::drawParagraph(PainterInfo & pi, pit_type const pit, int const
                // Row signature; has row changed since last paint?
                row.setCrc(pm.computeRowSignature(row, *bv_));
                bool row_has_changed = row.changed()
-                       || bv_->hadHorizScrollOffset(text_, pit, row.pos());
+                       || bv_->hadHorizScrollOffset(text_, pit, row.pos())
+                       || bv_->needRepaint(text_, row);
 
                // Take this opportunity to spellcheck the row contents.
                if (row_has_changed && pi.do_spellcheck && lyxrc.spellcheck_continuously) {

diff --git a/src/frontends/qt4/GuiWorkArea.cpp b/src/frontends/qt4/GuiWorkArea.cpp
index 0013670955294c8eb7094be488e6b36ec05838f2..9858d2929e75a7694e2524adcecaa82c5e0154d6 100644 (file)
--- a/src/frontends/qt4/GuiWorkArea.cpp
+++ b/src/frontends/qt4/GuiWorkArea.cpp
@@ -1170,9 +1170,10 @@ void GuiWorkArea::paintEvent(QPaintEvent * ev)
        }
 
        GuiPainter pain(viewport(), pixelRatio());
-       d->buffer_view_->draw(pain);
+       d->buffer_view_->draw(pain, d->cursor_visible_);
 
-       d->cursor_->draw(pain);
+       if (d->cursor_visible_)
+               d->cursor_->draw(pain);
        ev->accept();
 }