Fixed graph line distortion in PDF output

src/graph.h

@@ -15,6 +15,7 @@ public:
 	qreal s() const {return _s;}
 	qreal t() const {return _t;}
 	qreal y() const {return _y;}
+	qreal x(GraphType type) const {return (type == Distance) ? _s : _t;}
 
 	void setS(qreal s) {_s = s;}
 	void setT(qreal t) {_t = t;}

src/graphitem.cpp

@@ -5,37 +5,6 @@
 #define GRAPH_WIDTH 1
 #define HOVER_WIDTH 2
 
-static qreal yAtX(const QPainterPath &path, qreal x)
-{
-	int low = 0;
-	int high = path.elementCount() - 1;
-	int mid = 0;
-
-	Q_ASSERT(high > low);
-	Q_ASSERT(x >= path.elementAt(low).x && x <= path.elementAt(high).x);
-
-	while (low <= high) {
-		mid = low + ((high - low) / 2);
-		const QPainterPath::Element &e = path.elementAt(mid);
-		if (e.x > x)
-			high = mid - 1;
-		else if (e.x < x)
-			low = mid + 1;
-		else
-			return e.y;
-	}
-
-	QLineF l;
-	if (path.elementAt(mid).x < x)
-		l = QLineF(path.elementAt(mid).x, path.elementAt(mid).y,
-		  path.elementAt(mid+1).x, path.elementAt(mid+1).y);
-	else
-		l = QLineF(path.elementAt(mid-1).x, path.elementAt(mid-1).y,
-		  path.elementAt(mid).x, path.elementAt(mid).y);
-
-	return l.pointAt((x - l.p1().x()) / (l.p2().x() - l.p1().x())).y();
-}
-
 static bool hasTime(const Graph &graph)
 {
 	for (int i = 0; i < graph.count(); i++)
@@ -49,20 +18,16 @@ GraphItem::GraphItem(const Graph &graph, QGraphicsItem *parent)
   : QGraphicsObject(parent)
 {
 	_id = 0;
-	_type = Distance;
 
 	_pen = QPen(Qt::black, GRAPH_WIDTH);
-	_pen.setCosmetic(true);
 
-	_distancePath.moveTo(graph.first().s(), -graph.first().y());
+	_type = Distance;
-	for (int i = 1; i < graph.size(); i++)
+	_graph = graph;
-		_distancePath.lineTo(graph.at(i).s(), -graph.at(i).y());
+	_sx = 1.0; _sy = 1.0;
+	_time = hasTime(_graph);
 
-	if (hasTime(graph)) {
+	updatePath();
-		_timePath.moveTo(graph.first().t(), -graph.first().y());
+	updateBounds();
-		for (int i = 1; i < graph.size(); i++)
-			_timePath.lineTo(graph.at(i).t(), -graph.at(i).y());
-	}
 }
 
 void GraphItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
@@ -72,7 +37,7 @@ void GraphItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 	Q_UNUSED(widget);
 
 	painter->setPen(_pen);
-	painter->drawPath((_type == Distance) ? _distancePath : _timePath);
+	painter->drawPath(_path);
 
 /*
 	QPen p = QPen(QBrush(Qt::red), 0);
@@ -84,7 +49,10 @@ void GraphItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 void GraphItem::setGraphType(GraphType type)
 {
 	prepareGeometryChange();
+
 	_type = type;
+	updatePath();
+	updateBounds();
 }
 
 void GraphItem::setColor(const QColor &color)
@@ -95,37 +63,62 @@ void GraphItem::setColor(const QColor &color)
 
 qreal GraphItem::yAtX(qreal x)
 {
-	return ::yAtX((_type == Distance) ? _distancePath : _timePath, x);
+	int low = 0;
+	int high = _graph.count() - 1;
+	int mid = 0;
+
+	Q_ASSERT(high > low);
+	Q_ASSERT(x >= _graph.at(low).x(_type) && x <= _graph.at(high).x(_type));
+
+	while (low <= high) {
+		mid = low + ((high - low) / 2);
+		const GraphPoint &p = _graph.at(mid);
+		if (p.x(_type) > x)
+			high = mid - 1;
+		else if (p.x(_type) < x)
+			low = mid + 1;
+		else
+			return -p.y();
+	}
+
+	QLineF l;
+	if (_graph.at(mid).x(_type) < x)
+		l = QLineF(_graph.at(mid).x(_type), _graph.at(mid).y(),
+		  _graph.at(mid+1).x(_type), _graph.at(mid+1).y());
+	else
+		l = QLineF(_graph.at(mid-1).x(_type), _graph.at(mid-1).y(),
+		  _graph.at(mid).x(_type), _graph.at(mid).y());
+
+	return -l.pointAt((x - l.p1().x()) / (l.p2().x() - l.p1().x())).y();
 }
 
 qreal GraphItem::distanceAtTime(qreal time)
 {
 	int low = 0;
-	int high = _timePath.elementCount() - 1;
+	int high = _graph.count() - 1;
 	int mid = 0;
 
 	Q_ASSERT(high > low);
-	Q_ASSERT(time >= _timePath.elementAt(low).x
+	Q_ASSERT(time >= _graph.at(low).t() && time <= _graph.at(high).t());
-	  && time <= _timePath.elementAt(high).x);
 
 	while (low <= high) {
 		mid = low + ((high - low) / 2);
-		const QPainterPath::Element &e = _timePath.elementAt(mid);
+		const GraphPoint &p = _graph.at(mid);
-		if (e.x > time)
+		if (p.t() > time)
 			high = mid - 1;
-		else if (e.x < time)
+		else if (p.t() < time)
 			low = mid + 1;
 		else
-			return _distancePath.elementAt(mid).x;
+			return _graph.at(mid).s();
 	}
 
 	QLineF l;
-	if (_timePath.elementAt(mid).x < time)
+	if (_graph.at(mid).t() < time)
-		l = QLineF(_timePath.elementAt(mid).x, _distancePath.elementAt(mid).x,
+		l = QLineF(_graph.at(mid).t(), _graph.at(mid).s(), _graph.at(mid+1).t(),
-		  _timePath.elementAt(mid+1).x, _distancePath.elementAt(mid+1).x);
+		  _graph.at(mid+1).s());
 	else
-		l = QLineF(_timePath.elementAt(mid-1).x, _distancePath.elementAt(mid-1).x,
+		l = QLineF(_graph.at(mid-1).t(), _graph.at(mid-1).s(),
-		  _timePath.elementAt(mid).x, _distancePath.elementAt(mid).x);
+		  _graph.at(mid).t(), _graph.at(mid).s());
 
 	return l.pointAt((time - l.p1().x()) / (l.p2().x() - l.p1().x())).y();
 }
@@ -133,15 +126,13 @@ qreal GraphItem::distanceAtTime(qreal time)
 void GraphItem::emitSliderPositionChanged(qreal pos)
 {
 	if (_type == Time) {
-		if (!_timePath.isEmpty()) {
+		if (_time) {
-			if (pos <= _timePath.elementAt(_timePath.elementCount() - 1).x)
+			if (pos <= _graph.last().t())
 				emit sliderPositionChanged(distanceAtTime(pos));
 			else
-				emit sliderPositionChanged(_distancePath.elementAt(
+				emit sliderPositionChanged(_graph.last().s() + 1);
-			      _distancePath.elementCount() - 1).x + 1);
 		} else
-			emit sliderPositionChanged(_distancePath.elementAt(
+			emit sliderPositionChanged(_graph.last().s() + 1);
-		      _distancePath.elementCount() - 1).x + 1);
 	} else
 		emit sliderPositionChanged(pos);
 }
@@ -158,3 +149,47 @@ void GraphItem::selected(bool selected)
 
 	update();
 }
+
+void GraphItem::setScale(qreal sx, qreal sy)
+{
+	if (_sx == sx && _sy == sy)
+		return;
+
+	prepareGeometryChange();
+
+	_sx = sx; _sy = sy;
+	updatePath();
+}
+
+void GraphItem::updatePath()
+{
+	_path = QPainterPath();
+
+	if (_type == Time && !_time)
+		return;
+
+	_path.moveTo(_graph.first().x(_type) * _sx, -_graph.first().y() * _sy);
+	for (int i = 1; i < _graph.size(); i++)
+		_path.lineTo(_graph.at(i).x(_type) * _sx, -_graph.at(i).y() * _sy);
+}
+
+void GraphItem::updateBounds()
+{
+	if (_type == Time && !_time) {
+		_bounds = QRectF();
+		return;
+	}
+
+	qreal bottom, top, left, right;
+
+	QPointF p = QPointF(_graph.first().x(_type), -_graph.first().y());
+	bottom = p.y(); top = p.y(); left = p.x(); right = p.x();
+
+	for (int i = 1; i < _graph.size(); i++) {
+		p = QPointF(_graph.at(i).x(_type), -_graph.at(i).y());
+		bottom = qMax(bottom, p.y()); top = qMin(top, p.y());
+		right = qMax(right, p.x()); left = qMin(left, p.x());
+	}
+
+	_bounds = QRectF(QPointF(left, top), QPointF(right, bottom));
+}

src/graphitem.h

@@ -13,11 +13,13 @@ public:
 	GraphItem(const Graph &graph, QGraphicsItem *parent = 0);
 
 	QRectF boundingRect() const
-	  {return (_type == Distance) ? _distancePath.boundingRect()
+	  {return _path.boundingRect();}
-	  : _timePath.boundingRect();}
 	void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 	  QWidget *widget);
 
+	const QRectF &bounds() const {return _bounds;}
+	void setScale(qreal sx, qreal sy);
+
 	void setGraphType(GraphType type);
 	int id() const {return _id;}
 	void setId(int id) {_id = id;}
@@ -34,10 +36,19 @@ public slots:
 	void selected(bool selected);
 
 private:
+	void updatePath();
+	void updateBounds();
+
 	int _id;
 	QPen _pen;
-	QPainterPath _distancePath, _timePath;
+
+	Graph _graph;
 	GraphType _type;
+	bool _time;
+
+	QPainterPath _path;
+	QRectF _bounds;
+	qreal _sx, _sy;
 };
 
 #endif // GRAPHITEM_H

src/graphview.cpp

@@ -153,7 +153,7 @@ void GraphView::setGraphType(GraphType type)
 	for (int i = 0; i < _graphs.count(); i++) {
 		_graphs.at(i)->setGraphType(type);
 		if (_graphs.at(i)->scene() == _scene)
-			_bounds |= _graphs.at(i)->boundingRect();
+			_bounds |= _graphs.at(i)->bounds();
 	}
 
 	if (type == Distance)
@@ -186,7 +186,7 @@ void GraphView::loadGraph(const Graph &graph, PathItem *path, int id)
 	if (!_hide.contains(id)) {
 		_visible.append(gi);
 		_scene->addItem(gi);
-		_bounds |= gi->boundingRect();
+		_bounds |= gi->bounds();
 		setXUnits();
 	}
 }
@@ -219,7 +219,7 @@ void GraphView::showGraph(bool show, int id)
 		else {
 			addItem(gi);
 			_visible.append(gi);
-			_bounds |= gi->boundingRect();
+			_bounds |= gi->bounds();
 		}
 	}
 }
@@ -241,8 +241,7 @@ void GraphView::redraw(const QSizeF &size)
 	QRectF r;
 	QSizeF mx, my;
 	RangeF rx, ry;
-	QTransform transform;
+	qreal sx, sy;
-	qreal xs, ys;
 
 
 	if (_visible.isEmpty() || _bounds.isNull()) {
@@ -275,20 +274,19 @@ void GraphView::redraw(const QSizeF &size)
 		r.adjust(0, -(_minYRange/2 - r.height()/2), 0,
 		  _minYRange/2 - r.height()/2);
 
-	xs = (size.width() - (my.width() + mx.width())) / r.width();
+	sx = (size.width() - (my.width() + mx.width())) / r.width();
-	ys = (size.height() - (mx.height() + my.height())
+	sy = (size.height() - (mx.height() + my.height())
 	  - _info->boundingRect().height()) / r.height();
-	transform.scale(xs, ys);
 
 	for (int i = 0; i < _visible.size(); i++)
-		_visible.at(i)->setTransform(transform);
+		_visible.at(i)->setScale(sx, sy);
 
-	QPointF p(r.left() * xs, r.top() * ys);
+	QPointF p(r.left() * sx, r.top() * sy);
-	QSizeF s(r.width() * xs, r.height() * ys);
+	QSizeF s(r.width() * sx, r.height() * sy);
 	r = QRectF(p, s);
-	if (r.height() < _minYRange * ys)
+	if (r.height() < _minYRange * sy)
-		r.adjust(0, -(_minYRange/2 * ys - r.height()/2), 0,
+		r.adjust(0, -(_minYRange/2 * sy - r.height()/2), 0,
-		  (_minYRange/2) * ys - r.height()/2);
+		  (_minYRange/2) * sy - r.height()/2);
 
 	_xAxis->setSize(r.width());
 	_yAxis->setSize(r.height());
@@ -368,7 +366,7 @@ void GraphView::updateSliderInfo()
 	if (!_sliderInfo->isVisible())
 		return;
 
-	QRectF br(_visible.first()->boundingRect());
+	QRectF br(_visible.first()->bounds());
 	if (br.height() < _minYRange)
 		br.adjust(0, -(_minYRange/2 - br.height()/2), 0,
 		  _minYRange/2 - br.height()/2);