Make sure paragraph positions are updated when scrolling

Sometimes quick selection-scrolling could cause a crash because the
position of some paragraphs is not computed. To fix that, in
BufferView::showCursor, make sure that the metrics are always kept
clean using updateMetrics(false), which is lighweight.

As a consequence, the 'update' parameter of showCursor and
scrollDocView is not needed anymore. Its removal is mechanical and
accounts for most of this commit.

The only other significant change is that, when creating synthetic
mouse events and relying on scroll() for small moves, the full metrics
recomputation is replaced by the lighter version.

More work is still to come on this code, but this should be going in
the right direction.

diff --git a/src/BufferView.cpp b/src/BufferView.cpp
index 70d81567c1d3456b26e845e20b4fb67131fee71e..67aa4944f6dc012aade397a81f7873a16aa40ab1 100644 (file)
--- a/src/BufferView.cpp
+++ b/src/BufferView.cpp
@@ -763,7 +763,7 @@ Inset const * BufferView::mathContextMenu(InsetMathNest const * inset,
 }
 
 
-void BufferView::scrollDocView(int const pixels, bool update)
+void BufferView::scrollDocView(int const pixels)
 {
        // The scrollbar values are relative to the top of the screen, therefore the
        // offset is equal to the target value.
@@ -786,7 +786,7 @@ void BufferView::scrollDocView(int const pixels, bool update)
        // cut off at the top
        if (pixels <= d->scrollbarParameters_.min) {
                DocIterator dit = doc_iterator_begin(&buffer_);
-               showCursor(dit, SCROLL_VISIBLE, update);
+               showCursor(dit, SCROLL_VISIBLE);
                LYXERR(Debug::SCROLLING, "scroll to top");
                return;
        }
@@ -795,7 +795,7 @@ void BufferView::scrollDocView(int const pixels, bool update)
        if (pixels >= d->scrollbarParameters_.max) {
                DocIterator dit = doc_iterator_end(&buffer_);
                dit.backwardPos();
-               showCursor(dit, SCROLL_VISIBLE, update);
+               showCursor(dit, SCROLL_VISIBLE);
                LYXERR(Debug::SCROLLING, "scroll to bottom");
                return;
        }
@@ -814,14 +814,14 @@ void BufferView::scrollDocView(int const pixels, bool update)
                // It seems we didn't find the correct pit so stay on the safe side and
                // scroll to bottom.
                LYXERR0("scrolling position not found!");
-               scrollDocView(d->scrollbarParameters_.max, update);
+               scrollDocView(d->scrollbarParameters_.max);
                return;
        }
 
        DocIterator dit = doc_iterator_begin(&buffer_);
        dit.pit() = i;
        LYXERR(Debug::SCROLLING, "pixels = " << pixels << " -> scroll to pit " << i);
-       showCursor(dit, SCROLL_VISIBLE, update);
+       showCursor(dit, SCROLL_VISIBLE);
 }
 
 
@@ -1007,20 +1007,19 @@ int BufferView::workWidth() const
 
 void BufferView::recenter()
 {
-       showCursor(d->cursor_, SCROLL_CENTER, true);
+       showCursor(d->cursor_, SCROLL_CENTER);
 }
 
 
 void BufferView::showCursor()
 {
-       showCursor(d->cursor_, SCROLL_VISIBLE, true);
+       showCursor(d->cursor_, SCROLL_VISIBLE);
 }
 
 
-void BufferView::showCursor(DocIterator const & dit, ScrollType how,
-       bool update)
+void BufferView::showCursor(DocIterator const & dit, ScrollType how)
 {
-       if (scrollToCursor(dit, how) && update)
+       if (scrollToCursor(dit, how))
                processUpdateFlags(Update::ForceDraw);
 }
 

diff --git a/src/BufferView.h b/src/BufferView.h
index bfd523aa5705c353b301aede43566fba8adba3de..0b9ade2f3bd73aa1c4a753f70839d60f40a4cb35 100644 (file)
--- a/src/BufferView.h
+++ b/src/BufferView.h
@@ -219,8 +219,7 @@ public:
        /// This method will automatically scroll and update the BufferView
        /// (metrics+drawing) if needed.
        /// \param how Use this scroll strategy
-       /// \param force If true, update screen after scrolling
-       void showCursor(DocIterator const & dit, ScrollType how, bool update);
+       void showCursor(DocIterator const & dit, ScrollType how);
        /// Scroll to the cursor.
        /// \param how Use this scroll strategy
        /// \return true if screen was scrolled
@@ -232,7 +231,7 @@ public:
        /// scroll document by the given number of pixels.
        int scroll(int pixels);
        /// Scroll the view by a number of pixels.
-       void scrollDocView(int pixels, bool update);
+       void scrollDocView(int pixels);
        /// Set the cursor position based on the scrollbar one.
        void setCursorFromScrollbar();
 

diff --git a/src/frontends/qt/GuiWorkArea.cpp b/src/frontends/qt/GuiWorkArea.cpp
index 5c94f1e049607d82bb79ba759255037c4c348457..462fabda1e16c23999a7d3cf93d8ecfde016185b 100644 (file)
--- a/src/frontends/qt/GuiWorkArea.cpp
+++ b/src/frontends/qt/GuiWorkArea.cpp
@@ -586,7 +586,7 @@ void GuiWorkArea::Private::updateScrollbar()
 void GuiWorkArea::scrollTo(int value)
 {
        stopBlinkingCaret();
-       d->buffer_view_->scrollDocView(value, true);
+       d->buffer_view_->scrollDocView(value);
 
        if (lyxrc.cursor_follows_scrollbar) {
                d->buffer_view_->setCursorFromScrollbar();
@@ -959,9 +959,9 @@ void GuiWorkArea::generateSyntheticMouseEvent()
        // Scroll
        if (step <= 2 * wh) {
                d->buffer_view_->scroll(up ? -step : step);
-               d->buffer_view_->updateMetrics();
+               d->buffer_view_->processUpdateFlags(Update::ForceDraw);
        } else {
-               d->buffer_view_->scrollDocView(value + (up ? -step : step), false);
+               d->buffer_view_->scrollDocView(value + (up ? -step : step));
        }
 
        // In which paragraph do we have to set the cursor ?