Fix PageUp/Down select when at the top/bottom of a document.

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@23510 a592a061-630c-0410-9148-cb99ea01b6c8

src/BufferView.cpp

@@ -312,6 +312,18 @@ int BufferView::leftMargin() const
 }
 
 
+bool BufferView::isTopScreen() const
+{
+	return d->scrollbarParameters_.position == d->scrollbarParameters_.min;
+}
+
+
+bool BufferView::isBottomScreen() const
+{
+	return d->scrollbarParameters_.position == d->scrollbarParameters_.max;
+}
+
+
 Intl & BufferView::getIntl()
 {
 	return d->intl_;

src/BufferView.h

@@ -96,6 +96,12 @@ public:
 	/// left margin
 	int leftMargin() const;
 
+	/// \return true if the BufferView is at the top of the document.
+	bool isTopScreen() const;
+
+	/// \return true if the BufferView is at the bottom of the document.
+	bool isBottomScreen() const;
+
 	/// perform pending metrics updates.
 	/** \c Update::FitCursor means first to do a FitCursor, and to
 	 * force an update if screen position changes.

src/TextMetrics.cpp

@@ -1613,6 +1613,14 @@ int TextMetrics::cursorY(CursorSlice const & sl, bool boundary) const
 
 void TextMetrics::cursorPrevious(Cursor & cur)
 {
+	if (bv_->isTopScreen()) {
+		lyx::dispatch(FuncRequest(cur.selection()
+			? LFUN_BUFFER_BEGIN_SELECT : LFUN_BUFFER_BEGIN));
+		cur.finishUndo();
+		cur.updateFlags(Update::None);
+		return;
+	}
+
 	pos_type cpos = cur.pos();
 	pit_type cpar = cur.pit();
 
@@ -1638,6 +1646,14 @@ void TextMetrics::cursorPrevious(Cursor & cur)
 
 void TextMetrics::cursorNext(Cursor & cur)
 {
+	if (bv_->isBottomScreen()) {
+		lyx::dispatch(FuncRequest(cur.selection()
+			? LFUN_BUFFER_END_SELECT : LFUN_BUFFER_END));
+		cur.finishUndo();
+		cur.updateFlags(Update::None);
+		return;
+	}
+
 	pos_type cpos = cur.pos();
 	pit_type cpar = cur.pit();