Give PageDown/Up scrolling a sane behaviour. Does not work with selection yet...

* BufferView:
- new scroll(), scrollDown() and scrollUp() method for pixel scrolling.
- new LFUN_SCREEN_UP/DOWN handling.
 
* TextMetrics: new helper and access methods.




git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@20283 a592a061-630c-0410-9148-cb99ea01b6c8

src/BufferView.cpp

@@ -592,6 +592,18 @@ FuncStatus BufferView::getStatus(FuncRequest const & cmd)
 		break;
 	}
 
+	case LFUN_SCREEN_UP:
+	case LFUN_SCREEN_DOWN:
+		flag.enabled(true);
+		break;
+
+	// FIXME: LFUN_SCREEN_DOWN_SELECT should be removed from
+	// everywhere else before this can enabled:
+	case LFUN_SCREEN_UP_SELECT:
+	case LFUN_SCREEN_DOWN_SELECT:
+		flag.enabled(false);
+		break;
+
 	default:
 		flag.enabled(false);
 	}
@@ -935,6 +947,38 @@ Update::flags BufferView::dispatch(FuncRequest const & cmd)
 		break;
 	}
 
+	case LFUN_SCREEN_UP:
+	case LFUN_SCREEN_DOWN: {
+		Point const p = bv_funcs::getPos(*this, cur, cur.boundary());
+		scroll(cmd.action == LFUN_SCREEN_UP? - height_ : height_);
+		cur.reset(buffer_.inset());
+		text_metrics_[&buffer_.text()].editXY(cur, p.x_, p.y_);
+		//FIXME: what to do with cur.x_target()?
+		finishUndo();
+		// The metrics are already up to date. see scroll()
+		updateFlags = Update::None;
+		break;
+	}
+
+	case LFUN_SCREEN_UP_SELECT:
+	case LFUN_SCREEN_DOWN_SELECT: {
+		cur.selHandle(true);
+		size_t initial_depth = cur.depth();
+		Point const p = bv_funcs::getPos(*this, cur, cur.boundary());
+		scroll(cmd.action == LFUN_SCREEN_UP_SELECT? - height_ : height_);
+		// FIXME: We need to verify if the cursor stayed within an inset...
+		//cur.reset(buffer_.inset());
+		text_metrics_[&buffer_.text()].editXY(cur, p.x_, p.y_);
+		finishUndo();
+		while (cur.depth() > initial_depth) {
+			cur.forwardInset();
+		}
+		// FIXME: we need to do a redraw again because of the selection
+		buffer_.changed();
+		updateFlags = Update::Force | Update::FitCursor;
+		break;
+	}
+
 	default:
 		updateFlags = Update::None;
 	}
@@ -1138,20 +1182,60 @@ bool BufferView::workAreaDispatch(FuncRequest const & cmd0)
 }
 
 
-void BufferView::scroll(int /*lines*/)
+void BufferView::scroll(int y)
 {
-//	Text const * t = buffer_.text();
-//	int const line_height = defaultRowHeight();
-//
-//	// The new absolute coordinate
-//	int new_top_y = top_y() + lines * line_height;
-//
-//	// Restrict to a valid value
-//	new_top_y = std::min(t->height() - 4 * line_height, new_top_y);
-//	new_top_y = std::max(0, new_top_y);
-//
-//	scrollDocView(new_top_y);
-//
+	if (y > 0)
+		scrollDown(y);
+	else if (y < 0)
+		scrollUp(-y);
+}
+
+
+void BufferView::scrollDown(int offset)
+{
+	Text * text = &buffer_.text();
+	TextMetrics & tm = text_metrics_[text];
+	int ymax = height_ + offset;
+	while (true) {
+		std::pair<pit_type, ParagraphMetrics> const & last = tm.last();
+		int bottom_pos = last.second.position() + last.second.descent();
+		if (last.first == text->paragraphs().size() - 1) {
+			if (bottom_pos <= height_)
+				return;
+			offset = min(offset, bottom_pos - height_);
+			break;
+		}
+		if (bottom_pos > ymax)
+			break;
+		tm.newParMetricsDown();
+	}
+	offset_ref_ += offset;
+	updateMetrics(false);
+	buffer_.changed();
+}
+
+
+void BufferView::scrollUp(int offset)
+{
+	Text * text = &buffer_.text();
+	TextMetrics & tm = text_metrics_[text];
+	int ymin = - offset;
+	while (true) {
+		std::pair<pit_type, ParagraphMetrics> const & first = tm.first();
+		int top_pos = first.second.position() - first.second.ascent();
+		if (first.first == 0) {
+			if (top_pos >= 0)
+				return;
+			offset = min(offset, - top_pos);
+			break;
+		}
+		if (top_pos < ymin)
+			break;
+		tm.newParMetricsUp();
+	}
+	offset_ref_ -= offset;
+	updateMetrics(false);
+	buffer_.changed();
 }
 
 

src/BufferView.h

@@ -128,8 +128,12 @@ public:
 
 	/// center the document view around the cursor.
 	void center();
-	/// scroll document by the given number of lines of default height.
-	void scroll(int lines);
+	/// scroll down document by the given number of pixels.
+	void scrollDown(int pixels);
+	/// scroll up document by the given number of pixels.
+	void scrollUp(int pixels);
+	/// scroll document by the given number of pixels.
+	void scroll(int pixels);
 	/// Scroll the view by a number of pixels.
 	void scrollDocView(int pixels);
 	/// Set the cursor position based on the scrollbar one.

src/Text3.cpp

@@ -440,9 +440,8 @@ void Text::dispatch(Cursor & cur, FuncRequest & cmd)
 		needsUpdate |= cursorDownParagraph(cur);
 		break;
 
-	case LFUN_SCREEN_UP:
 	case LFUN_SCREEN_UP_SELECT:
-		needsUpdate |= cur.selHandle(cmd.action == LFUN_SCREEN_UP_SELECT);
+		needsUpdate |= cur.selHandle(true);
 		if (cur.pit() == 0 && cur.textRow().pos() == 0)
 			cur.undispatched();
 		else {
@@ -450,9 +449,8 @@ void Text::dispatch(Cursor & cur, FuncRequest & cmd)
 		}
 		break;
 
-	case LFUN_SCREEN_DOWN:
 	case LFUN_SCREEN_DOWN_SELECT:
-		needsUpdate |= cur.selHandle(cmd.action == LFUN_SCREEN_DOWN_SELECT);
+		needsUpdate |= cur.selHandle(true);
 		if (cur.pit() == cur.lastpit()
 			  && cur.textRow().endpos() == cur.lastpos())
 			cur.undispatched();
@@ -1853,8 +1851,6 @@ bool Text::getStatus(Cursor & cur, FuncRequest const & cmd,
 	case LFUN_WORD_SELECT:
 	case LFUN_PARAGRAPH_UP:
 	case LFUN_PARAGRAPH_DOWN:
-	case LFUN_SCREEN_UP:
-	case LFUN_SCREEN_DOWN:
 	case LFUN_LINE_BEGIN:
 	case LFUN_LINE_END:
 	case LFUN_BREAK_LINE:

src/TextMetrics.cpp

@@ -139,6 +139,21 @@ ParagraphMetrics const & TextMetrics::parMetrics(pit_type pit) const
 }
 
 
+
+pair<pit_type, ParagraphMetrics> const & TextMetrics::first() const
+{
+	pair<pit_type, ParagraphMetrics> const & pm = *par_metrics_.begin();
+	return pm;
+}
+
+
+pair<pit_type, ParagraphMetrics> const & TextMetrics::last() const
+{
+	pair<pit_type, ParagraphMetrics> const & pm = *par_metrics_.rbegin();
+	return pm;
+}
+
+
 ParagraphMetrics & TextMetrics::parMetrics(pit_type pit,
 		bool redo)
 {
@@ -1153,6 +1168,33 @@ pos_type TextMetrics::x2pos(pit_type pit, int row, int x) const
 }
 
 
+void TextMetrics::newParMetricsDown()
+{
+	pair<pit_type, ParagraphMetrics> const & last = *par_metrics_.rbegin();
+	pit_type const pit = last.first + 1;
+	if (pit == text_->paragraphs().size())
+		return;
+
+	// do it and update its position.
+	redoParagraph(pit);
+	par_metrics_[pit].setPosition(last.second.position()
+		+ last.second.descent());
+}
+
+
+void TextMetrics::newParMetricsUp()
+{
+	pair<pit_type, ParagraphMetrics> const & first = *par_metrics_.begin();
+	if (first.first == 0)
+		return;
+
+	pit_type const pit = first.first - 1;
+	// do it and update its position.
+	redoParagraph(pit);
+	par_metrics_[pit].setPosition(first.second.position()
+		- first.second.ascent());
+}
+
 // y is screen coordinate
 pit_type TextMetrics::getPitNearY(int y)
 {

src/TextMetrics.h

@@ -48,6 +48,11 @@ public:
 	bool has(pit_type pit) const;
 	///
 	ParagraphMetrics const & parMetrics(pit_type) const;
+	///
+	std::pair<pit_type, ParagraphMetrics> const & first() const;
+	///
+	std::pair<pit_type, ParagraphMetrics> const & last() const;
+
 	///
 	int parPosition(pit_type pit) const;
 
@@ -57,9 +62,15 @@ public:
 	Point const & origin() const { return origin_; }
 
 
+
 	/// compute text metrics.
 	bool metrics(MetricsInfo & mi, Dimension & dim);
 
+	///
+	void newParMetricsDown();
+	///
+	void newParMetricsUp();
+
 	/// 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

src/mathed/InsetMathNest.cpp

@@ -643,13 +643,11 @@ goto_char_backwards:
 		break;
 
 	case LFUN_SCREEN_UP_SELECT:
-	case LFUN_SCREEN_UP:
 		cmd = FuncRequest(LFUN_FINISHED_LEFT);
 		cur.undispatched();
 		break;
 
 	case LFUN_SCREEN_DOWN_SELECT:
-	case LFUN_SCREEN_DOWN:
 		cmd = FuncRequest(LFUN_FINISHED_RIGHT);
 		cur.undispatched();
 		break;