[LyX/master] Update insets position in cache in more cases

[Jean-Marc Lasgouttes]

commit 3b404b0023e611bfbdb64fa723c5d56d7477fcf7
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Wed Aug 30 18:05:16 2017 +0200

    Update insets position in cache in more cases
    
    This patch makes sure that, every time a ParagraphMetrics has its
    position set, the inset positions for the insets held by this
    paragraph are remembered too.
    
    This is complementary to BufferView::updatePosCache, but I do not have
    hard evidence that this is required other than to increase robustness.
    It may help in some cases when scrolling the document (scrollbar,
    cursor up/down, page up/down).
---
 src/BufferView.cpp  |    4 ++++
 src/TextMetrics.cpp |   11 +++++++++++
 src/TextMetrics.h   |    5 +++++
 3 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/src/BufferView.cpp b/src/BufferView.cpp
index 1673de1..ab264ba 100644
--- a/src/BufferView.cpp
+++ b/src/BufferView.cpp
@@ -2658,6 +2658,7 @@ bool BufferView::singleParUpdate()
                // the singlePar optimisation.
                return false;
 
+       tm.updatePosCache(bottom_pit);
        d->update_strategy_ = SingleParUpdate;
 
        LYXERR(Debug::PAINTING, "\ny1: " << pm.position() - pm.ascent()
@@ -2711,6 +2712,7 @@ void BufferView::updateMetrics()
                // in the first line.
        }
        anchor_pm.setPosition(d->anchor_ypos_);
+       tm.updatePosCache(d->anchor_pit_);
 
        LYXERR(Debug::PAINTING, "metrics: "
                << " anchor pit = " << d->anchor_pit_
@@ -2726,6 +2728,7 @@ void BufferView::updateMetrics()
                y1 -= pm.descent();
                // Save the paragraph position in the cache.
                pm.setPosition(y1);
+               tm.updatePosCache(pit1);
                y1 -= pm.ascent();
        }
 
@@ -2739,6 +2742,7 @@ void BufferView::updateMetrics()
                y2 += pm.ascent();
                // Save the paragraph position in the cache.
                pm.setPosition(y2);
+               tm.updatePosCache(pit2);
                y2 += pm.descent();
        }
 
diff --git a/src/TextMetrics.cpp b/src/TextMetrics.cpp
index c6f6bbf..c88e5c6 100644
--- a/src/TextMetrics.cpp
+++ b/src/TextMetrics.cpp
@@ -43,6 +43,7 @@
 
 #include "frontends/FontMetrics.h"
 #include "frontends/Painter.h"
+#include "frontends/NullPainter.h"
 
 #include "support/debug.h"
 #include "support/lassert.h"
@@ -198,6 +199,14 @@ bool TextMetrics::metrics(MetricsInfo & mi, Dimension & 
dim, int min_width)
 }
 
 
+void TextMetrics::updatePosCache(pit_type pit) const
+{
+       frontend::NullPainter np;
+       PainterInfo pi(bv_, np);
+       drawParagraph(pi, pit, origin_.x_, par_metrics_[pit].position());
+}
+
+
 int TextMetrics::rightMargin(ParagraphMetrics const & pm) const
 {
        return text_->isMainText() ? pm.rightMargin(*bv_) : 0;
@@ -1219,6 +1228,7 @@ void TextMetrics::newParMetricsDown()
        redoParagraph(pit);
        par_metrics_[pit].setPosition(last.second.position()
                + last.second.descent() + par_metrics_[pit].ascent());
+       updatePosCache(pit);
 }
 
 
@@ -1233,6 +1243,7 @@ void TextMetrics::newParMetricsUp()
        redoParagraph(pit);
        par_metrics_[pit].setPosition(first.second.position()
                - first.second.ascent() - par_metrics_[pit].descent());
+       updatePosCache(pit);
 }
 
 // y is screen coordinate
diff --git a/src/TextMetrics.h b/src/TextMetrics.h
index 3000b21..ae99490 100644
--- a/src/TextMetrics.h
+++ b/src/TextMetrics.h
@@ -62,6 +62,11 @@ public:
        ///
        void newParMetricsUp();
 
+       /// The "nodraw" drawing stage for one single paragraph: set the
+       /// positions of the insets contained this paragraph in metrics
+       /// cache. Related to BufferView::updatePosCache.
+       void updatePosCache(pit_type pit) const;
+
        /// Gets the fully instantiated font at a given position in a paragraph
        /// Basically the same routine as Paragraph::getFont() in Paragraph.cpp.
        /// The difference is that this one is used for displaying, and thus we