Fix scrolling to top and bottom of the document.

* BufferView
- showCursor(DocIterator): new DocIterator argument.
- showCursor(): use above method.
- scrollDocView(): take care of top and bottom special cases early in the method.


git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@22707 a592a061-630c-0410-9148-cb99ea01b6c8

src/BufferView.cpp

@@ -501,6 +501,24 @@ docstring BufferView::contextMenu(int x, int y) const
 
 void BufferView::scrollDocView(int value)
 {
+	// cut off at the top
+	if (value <= d->scrollbarParameters_.min) {
+		DocIterator dit = doc_iterator_begin(buffer_.inset());
+		showCursor(dit);
+		LYXERR(Debug::SCROLLING, "scroll to top");
+		return;
+	}
+
+	// cut off at the top
+	if (value >= d->scrollbarParameters_.max) {
+		DocIterator dit = doc_iterator_end(buffer_.inset());
+		dit.backwardPos();
+		showCursor(dit);
+		LYXERR(Debug::SCROLLING, "scroll to bottom");
+		return;
+	}
+
+
 	int const offset = value - d->scrollbarParameters_.position;
 	// If the offset is less than 2 screen height, prefer to scroll instead.
 	if (abs(offset) <= 2 * height_) {
@@ -508,10 +526,6 @@ void BufferView::scrollDocView(int value)
 		return;
 	}
 
-	// cut off at the top
-	if (value < d->scrollbarParameters_.min)
-		value = d->scrollbarParameters_.min;
-
 	// find paragraph at target positin
 	int par_pos = d->scrollbarParameters_.min;
 	for (size_t i = 0; i != d->par_height_.size(); ++i) {
@@ -703,6 +717,12 @@ int BufferView::workWidth() const
 
 
 void BufferView::showCursor()
+{
+	showCursor(d->cursor_);
+}
+
+
+void BufferView::showCursor(DocIterator const & dit)
 {
 	// We are not properly started yet, delay until resizing is
 	// done.
@@ -711,11 +731,11 @@ void BufferView::showCursor()
 
 	LYXERR(Debug::SCROLLING, "recentering!");
 
-	CursorSlice & bot = d->cursor_.bottom();
+	CursorSlice const & bot = dit.bottom();
 	TextMetrics & tm = d->text_metrics_[bot.text()];
 
 	pos_type const max_pit = pos_type(bot.text()->paragraphs().size() - 1);
-	int bot_pit = d->cursor_.bottom().pit();
+	int bot_pit = bot.pit();
 	if (bot_pit > max_pit) {
 		// FIXME: Why does this happen?
 		LYXERR0("bottom pit is greater that max pit: "
@@ -730,9 +750,13 @@ void BufferView::showCursor()
 
 	if (tm.has(bot_pit)) {
 		ParagraphMetrics const & pm = tm.parMetrics(bot_pit);
-		int offset = coordOffset(d->cursor_, d->cursor_.boundary()).y_;
+		BOOST_ASSERT(!pm.rows().empty());
+		// FIXME: smooth scrolling doesn't work in mathed.
+		CursorSlice const & cs = dit.innerTextSlice();
+		int offset = coordOffset(dit, dit.boundary()).y_;
 		int ypos = pm.position() + offset;
-		Dimension const & row_dim = d->cursor_.textRow().dimension();
+		Dimension const & row_dim =
+			pm.getRow(cs.pos(), dit.boundary()).dimension();
 		if (ypos - row_dim.ascent() < 0)
 			scrollUp(- ypos + row_dim.ascent());
 		else if (ypos + row_dim.descent() > height_)
@@ -743,10 +767,12 @@ void BufferView::showCursor()
 
 	tm.redoParagraph(bot_pit);
 	ParagraphMetrics const & pm = tm.parMetrics(bot_pit);
-	int offset = coordOffset(d->cursor_, d->cursor_.boundary()).y_;
+	int offset = coordOffset(dit, dit.boundary()).y_;
 
 	d->anchor_pit_ = bot_pit;
-	Dimension const & row_dim = d->cursor_.textRow().dimension();
+	CursorSlice const & cs = dit.innerTextSlice();
+	Dimension const & row_dim =
+		pm.getRow(cs.pos(), dit.boundary()).dimension();
 
 	if (d->anchor_pit_ == 0)
 		d->anchor_ypos_ = offset + pm.ascent();

src/BufferView.h

@@ -127,10 +127,14 @@ public:
 	/// set the cursor based on the given TeX source row.
 	void setCursorFromRow(int row);
 
-	/// Ensure the cursor is visible.
+	/// Ensure that the BufferView cursor is visible.
-	/// This method will automatically scroll and update the BufferView and updated 
+	/// This method will automatically scroll and update the BufferView
 	/// if needed.
 	void showCursor();
+	/// Ensure the passed cursor \p dit is visible.
+	/// This method will automatically scroll and update the BufferView
+	/// if needed.
+	void showCursor(DocIterator const & dit);
 	/// LFUN_SCROLL Helper.
 	void lfunScroll(FuncRequest const & cmd);
 	/// scroll down document by the given number of pixels.