* BufferView: Make use of ScreenUpdateStrategy::NoScreenUpdate, avoid a screen redraw when it is not really needed.

* Painter.h: move isDrawingEnabled() to public Area.

* TextMetrics::drawParagraph(): backup and restore original drawing state of the Painter.

* InsetTabular::draw(): ditto.

* InsetMathNest::drawSelection(): ditto.


git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@21471 a592a061-630c-0410-9148-cb99ea01b6c8

src/BufferView.cpp

@@ -1334,6 +1334,8 @@ Update::flags BufferView::dispatch(FuncRequest const & cmd)
 			updateMetrics();
 			//FIXME: updateMetrics() does not update paragraph position
 			// This is done at draw() time. So we need a redraw!
+			// But no screen update is needed.
+			d->metrics_info_.update_strategy = NoScreenUpdate;
 			buffer_.changed();
 			p = getPos(cur, cur.boundary());
 		}
@@ -1361,6 +1363,8 @@ Update::flags BufferView::dispatch(FuncRequest const & cmd)
 			cur.forwardInset();
 		}
 		// FIXME: we need to do a redraw again because of the selection
+		// But no screen update is needed.
+		d->metrics_info_.update_strategy = NoScreenUpdate;
 		buffer_.changed();
 		updateFlags = Update::Force | Update::FitCursor;
 		break;
@@ -2084,41 +2088,56 @@ Point BufferView::getPos(DocIterator const & dit, bool boundary) const
 
 void BufferView::draw(frontend::Painter & pain)
 {
+	LYXERR(Debug::PAINTING) << "\t\t*** START DRAWING ***" << endl;
+	Text & text = buffer_.text();
+	TextMetrics const & tm = d->text_metrics_[&text];
+	int const y = d->metrics_info_.y1 
+		+ tm.parMetrics(d->metrics_info_.p1).ascent();
 	PainterInfo pi(this, pain);
-	// Should the whole screen, including insets, be refreshed?
-	// FIXME: We should also distinguish DecorationUpdate to avoid text
-	// drawing if possible. This is not possible to do easily right now
-	// because of the single backing pixmap.
-	pi.full_repaint = d->metrics_info_.update_strategy != SingleParUpdate;
 
-	if (pi.full_repaint)
+	switch (d->metrics_info_.update_strategy) {
+
+	case NoScreenUpdate:
+		// If no screen painting is actually needed, only some the different
+		// coordinates of insets and paragraphs needs to be updated.
+		pi.pain.setDrawingEnabled(false);
+		pi.full_repaint = true;
+		break;
+
+	case SingleParUpdate:
+		// Only the current outermost paragraph will be redrawn.
+		pi.full_repaint = false;
+		tm.drawParagraph(pi, d->metrics_info_.p1, 0, y);
+		break;
+
+	case DecorationUpdate:
+		// FIXME: We should also distinguish DecorationUpdate to avoid text
+		// drawing if possible. This is not possible to do easily right now
+		// because of the single backing pixmap.
+
+	case FullScreenUpdate:
+		// The whole screen, including insets, will be refreshed.
+		pi.full_repaint = true;
+
 		// Clear background (if not delegated to rows)
 		pain.fillRectangle(0, d->metrics_info_.y1, width_,
 			d->metrics_info_.y2 - d->metrics_info_.y1,
 			buffer_.inset().backgroundColor());
-
-	LYXERR(Debug::PAINTING) << "\t\t*** START DRAWING ***" << endl;
-	Text & text = buffer_.text();
-	TextMetrics const & tm = d->text_metrics_[&text];
-	int y = d->metrics_info_.y1 + tm.parMetrics(d->metrics_info_.p1).ascent();
-	if (!pi.full_repaint)
-		tm.drawParagraph(pi, d->metrics_info_.p1, 0, y);
-	else
 		tm.draw(pi, 0, y);
+
+		// and grey out above (should not happen later)
+		if (d->metrics_info_.y1 > 0)
+			pain.fillRectangle(0, 0, width_,
+				d->metrics_info_.y1, Color_bottomarea);
+
+		// and possibly grey out below
+		if (d->metrics_info_.y2 < height_)
+			pain.fillRectangle(0, d->metrics_info_.y2, width_,
+				height_ - d->metrics_info_.y2, Color_bottomarea);
+		break;
+	}
+
 	LYXERR(Debug::PAINTING) << "\n\t\t*** END DRAWING  ***" << endl;
-
-	// and grey out above (should not happen later)
-//	lyxerr << "par ascent: " << text.getPar(d->metrics_info_.p1).ascent() << endl;
-	if (d->metrics_info_.y1 > 0
-		&& d->metrics_info_.update_strategy == FullScreenUpdate)
-		pain.fillRectangle(0, 0, width_, d->metrics_info_.y1, Color_bottomarea);
-
-	// and possibly grey out below
-//	lyxerr << "par descent: " << text.getPar(d->metrics_info_.p1).ascent() << endl;
-	if (d->metrics_info_.y2 < height_
-		&& d->metrics_info_.update_strategy == FullScreenUpdate)
-		pain.fillRectangle(0, d->metrics_info_.y2, width_,
-			height_ - d->metrics_info_.y2, Color_bottomarea);
 }
 
 

src/TextMetrics.cpp

@@ -1925,6 +1925,8 @@ void TextMetrics::drawParagraph(PainterInfo & pi, pit_type pit, int x, int y) co
 
 	Bidi bidi;
 
+	bool const original_drawing_state = pi.pain.isDrawingEnabled();
+
 	y -= rb->ascent();
 	for (RowList::const_iterator rit = rb; rit != re; ++rit) {
 		y += rit->ascent();
@@ -1932,7 +1934,7 @@ void TextMetrics::drawParagraph(PainterInfo & pi, pit_type pit, int x, int y) co
 		bool const inside = (y + rit->descent() >= 0
 			&& y - rit->ascent() < ww);
 		// it is not needed to draw on screen if we are not inside.
-		pi.pain.setDrawingEnabled(inside);
+		pi.pain.setDrawingEnabled(inside && original_drawing_state);
 		RowPainter rp(pi, *text_, pit, *rit, bidi, x, y);
 
 		// Row signature; has row changed since last paint?
@@ -1998,7 +2000,7 @@ void TextMetrics::drawParagraph(PainterInfo & pi, pit_type pit, int x, int y) co
 		pi.full_repaint = tmp;
 	}
 	// Re-enable screen drawing for future use of the painter.
-	pi.pain.setDrawingEnabled(true);
+	pi.pain.setDrawingEnabled(original_drawing_state);
 
 	//LYXERR(Debug::PAINTING) << "." << endl;
 }

src/frontends/Painter.h

@@ -144,6 +144,9 @@ public:
 	void setDrawingEnabled(bool drawing_enabled = true)
 	{ drawing_enabled_ = drawing_enabled; }
 
+	/// Indicate wether real screen drawing shall be done or not.
+	bool isDrawingEnabled() const { return drawing_enabled_; }
+
 	/// draw a char at position x, y (y is the baseline)
 	/**
 	* \return the width of the drawn text.
@@ -188,9 +191,6 @@ protected:
 	/// draw a bevelled button border
 	void buttonFrame(int x, int y, int w, int h);
 
-	/// Indicate wether real screen drawing shall be done or not.
-	bool isDrawingEnabled() const { return drawing_enabled_; }
-
 private:
 	///
 	bool drawing_enabled_;

src/insets/InsetTabular.cpp

@@ -3013,6 +3013,8 @@ void InsetTabular::draw(PainterInfo & pi, int x, int y) const
 	x += scx_;
 	x += ADD_TO_TABULAR_WIDTH;
 
+	bool const original_drawing_state = pi.pain.isDrawingEnabled();
+
 	idx_type idx = 0;
 	first_visible_cell = Tabular::npos;
 	for (row_type i = 0; i < tabular.rowCount(); ++i) {
@@ -3036,7 +3038,7 @@ void InsetTabular::draw(PainterInfo & pi, int x, int y) const
 				pi.pain.setDrawingEnabled(false);
 				cell(idx)->draw(pi, cx, y);
 				drawCellLines(pi.pain, nx, y, i, idx, pi.erased_);
-				pi.pain.setDrawingEnabled(true);
+				pi.pain.setDrawingEnabled(original_drawing_state);
 			} else {
 				cell(idx)->draw(pi, cx, y);
 				drawCellLines(pi.pain, nx, y, i, idx, pi.erased_);

src/mathed/InsetMathNest.cpp

@@ -246,9 +246,10 @@ void InsetMathNest::drawSelection(PainterInfo & pi, int x, int y) const
 		return;
 
 	// FIXME: hack to get position cache warm
+	bool const original_drawing_state = pi.pain.isDrawingEnabled();
 	pi.pain.setDrawingEnabled(false);
 	draw(pi, x, y);
-	pi.pain.setDrawingEnabled(true);
+	pi.pain.setDrawingEnabled(original_drawing_state);
 
 	CursorSlice s1 = cur.selBegin();
 	CursorSlice s2 = cur.selEnd();