Redesigned text path handling

src/style.cpp

@@ -269,8 +269,8 @@ bool Style::Layer::Paint::antialias(Layer::Type type) const
 }
 
 Style::Layer::Layout::Layout(const QJsonObject &json)
-  : _textSize(16), _textMaxWidth(10), _textMaxAngle(45), _symbolSpacing(250),
-  _lineCap(Qt::FlatCap), _lineJoin(Qt::MiterJoin), _capitalize(false)
+  : _textSize(16), _textMaxWidth(10), _textMaxAngle(45), _lineCap(Qt::FlatCap),
+  _lineJoin(Qt::MiterJoin), _capitalize(false)
 {
 	if (!(json.contains("text-field") && json["text-field"].isString()))
 		return;
@@ -298,11 +298,6 @@ Style::Layer::Layout::Layout(const QJsonObject &json)
 	else if (json.contains("text-max-angle") && json["text-max-angle"].isDouble())
 		_textMaxWidth = json["text-max-angle"].toDouble();
 
-	if (json.contains("symbol-spacing") && json["symbol-spacing"].isObject())
-		_symbolSpacing = json["symbol-spacing"].toObject();
-	else if (json.contains("symbol-spacing") && json["symbol-spacing"].isDouble())
-		_symbolSpacing = json["symbol-spacing"].toDouble();
-
 	if (json.contains("text-transform") && json["text-transform"].isString())
 		_capitalize = json["text-transform"].toString() == "uppercase";
 
@@ -422,8 +417,7 @@ void Style::Layer::drawSymbol(int zoom, const QPainterPath &path,
 		tile.text().addLabel(tt, path.elementAt(0), font, pen,
 		  _layout.maxTextWidth(zoom));
 	else
-		tile.text().addLabel(tt, path, font, pen,
-		  _layout.maxTextAngle(zoom), _layout.symbolSpacing(zoom));
+		tile.text().addLabel(tt, path, font, pen, _layout.maxTextAngle(zoom));
 }
 
 bool Style::load(const QString &fileName)

src/style.h

@@ -79,8 +79,8 @@ private:
 		class Layout {
 		public:
 			Layout() : _textSize(16), _textMaxWidth(10), _textMaxAngle(45),
-			  _symbolSpacing(250), _lineCap(Qt::FlatCap),
-			  _lineJoin(Qt::MiterJoin), _capitalize(false) {}
+			  _lineCap(Qt::FlatCap), _lineJoin(Qt::MiterJoin),
+			  _capitalize(false) {}
 			Layout(const QJsonObject &json);
 
 			bool capitalize() const {return _capitalize;}
@@ -88,8 +88,6 @@ private:
 			  {return _textMaxWidth.value(zoom);}
 			qreal maxTextAngle(int zoom) const
 			  {return _textMaxAngle.value(zoom);}
-			qreal symbolSpacing(int zoom) const
-			  {return _symbolSpacing.value(zoom);}
 			const QString &field() const {return _textField;}
 			const QStringList &keys() const {return _keys;}
 			QFont font(int zoom) const;
@@ -102,7 +100,6 @@ private:
 			FunctionF _textSize;
 			FunctionF _textMaxWidth;
 			FunctionF _textMaxAngle;
-			FunctionF _symbolSpacing;
 			Qt::PenCapStyle _lineCap;
 			Qt::PenJoinStyle _lineJoin;
 			bool _capitalize;

src/text.cpp

@@ -6,61 +6,123 @@
 #include "textpathitem.h"
 
 
-static QPainterPath subpath(const QPainterPath &path, int start, int end,
+static QPointF intersection(const QLineF &line, const QRectF &rect)
+{
+	QPointF p;
+	if (line.intersect(QLineF(rect.topLeft(), rect.topRight()), &p)
+	  == QLineF::BoundedIntersection)
+		return p;
+	if (line.intersect(QLineF(rect.topLeft(), rect.bottomLeft()), &p)
+	  == QLineF::BoundedIntersection)
+		return p;
+	if (line.intersect(QLineF(rect.bottomRight(), rect.bottomLeft()), &p)
+	  == QLineF::BoundedIntersection)
+		return p;
+	if (line.intersect(QLineF(rect.bottomRight(), rect.topRight()), &p)
+	  == QLineF::BoundedIntersection)
+		return p;
+
+	return rect.center();
+}
+
+static QPainterPath subpath(const QList<QLineF> &lines, int start, int end,
   qreal cut)
 {
-	QPainterPath p(path.elementAt(start));
+	qreal ss = 0, es = 0;
+	int si = start, ei = end;
 
-	for (int i = start + 1; i < end; i++)
-		p.lineTo(path.elementAt(i));
+	for (int i = start; i <= end; i++) {
+		qreal len = lines.at(i).length();
+		if (ss + len < cut / 2) {
+			ss += len;
+			si++;
+		} else
+			break;
+	}
+	for (int i = end; i >= start; i--) {
+		qreal len = lines.at(i).length();
+		if (es + len < cut / 2) {
+			es += len;
+			ei--;
+		} else
+			break;
+	}
 
-	QLineF l(path.elementAt(end - 1), path.elementAt(end));
-	l.setLength(l.length() - cut);
-	p.lineTo(l.p2());
+	QLineF sl(lines.at(si).p2(), lines.at(si).p1());
+	sl.setLength(sl.length() - (cut / 2 - ss));
+	QLineF el(lines.at(ei));
+	el.setLength(el.length() - (cut / 2 - es));
+
+	QPainterPath p(sl.p2());
+	for (int i = si; i <= ei; i++)
+		p.lineTo(lines.at(i).p2());
+	p.setElementPositionAt(p.elementCount() - 1, el.p2().x(), el.p2().y());
 
 	return p;
 }
 
-static QList<QPainterPath> segments(const QPainterPath &path, qreal textLength,
-  qreal maxAngle, qreal charWidth, int symbolSpacing, const QRectF &tileRect)
+static QList<QLineF> lineString(const QPainterPath &path,
+  const QRectF &boundingRect)
 {
-	QList<QPainterPath> list;
-	int start = 0;
-	qreal length = 0;
-	qreal angle = -1;
-	qreal dist = symbolSpacing;
+	QList<QLineF> lines;
+	int start = 0, end = path.elementCount() - 1;
 
-	for (int i = 1; i < path.elementCount(); i++) {
-		QLineF l(path.elementAt(i-1), path.elementAt(i));
-		qreal sl = l.length();
-
-		if (dist < symbolSpacing) {
-			dist += sl;
-			start++;
-			continue;
-		}
-
-		qreal a = l.angle();
-		if (angle < 0)
-			angle = a;
-
-		if (!tileRect.contains(path.elementAt(i))
-		  || sl < charWidth || qAbs(angle - a) > maxAngle
-		  || length > textLength) {
-			if (length > textLength) {
-				list.append(subpath(path, start, i - 1, length - textLength - 1));
-				dist = 0;
-			}
+	for (int i = 0; i < path.elementCount(); i++) {
+		if (boundingRect.contains(path.elementAt(i))) {
 			start = i;
+			break;
+		}
+	}
+	for (int i = path.elementCount() - 1; i >= 0; i--) {
+		if (boundingRect.contains(path.elementAt(i))) {
+			end = i;
+			break;
+		}
+	}
+
+	if (start > 0) {
+		QLineF l(path.elementAt(start-1), path.elementAt(start));
+		QPointF p(intersection(l, boundingRect));
+		if (p != boundingRect.center())
+			lines.append(QLineF(p, path.elementAt(start)));
+	}
+	for (int i = start + 1; i <= end; i++)
+		lines.append(QLineF(path.elementAt(i-1), path.elementAt(i)));
+	if (end < path.elementCount() - 1) {
+		QLineF l(path.elementAt(end), path.elementAt(end+1));
+		QPointF p(intersection(l, boundingRect));
+		if (p != boundingRect.center())
+			lines.append(QLineF(path.elementAt(end), p));
+	}
+
+	return lines;
+}
+
+static QPainterPath textPath(const QPainterPath &path, qreal textWidth,
+  qreal maxAngle, qreal charWidth, const QRectF &tileRect)
+{
+	QList<QLineF> lines(lineString(path, tileRect));
+	qreal length = 0;
+	qreal angle = lines.first().angle();
+	int last = 0;
+
+	for (int i = 0; i < lines.size(); i++) {
+		qreal sl = lines.at(i).length();
+		qreal a = lines.at(i).angle();
+
+		if (!tileRect.contains(lines.at(i).p2()) || sl < charWidth
+		  || qAbs(angle - a) > maxAngle) {
+			if (length > textWidth)
+				return subpath(lines, last, i - 1, length - textWidth);
+			last = i;
 			length = 0;
 		} else
 			length += sl;
 
-		dist += sl;
 		angle = a;
 	}
 
-	return list;
+	return QPainterPath();
 }
 
 static bool reverse(const QPainterPath &path)
@@ -93,9 +155,9 @@ void Text::addLabel(const QString &text, const QPointF &pos, const QFont &font,
 }
 
 void Text::addLabel(const QString &text, const QPainterPath &path,
-  const QFont &font, const QPen &pen, qreal maxAngle, qreal symbolSpacing)
+  const QFont &font, const QPen &pen, qreal maxAngle)
 {
-	if (path.elementCount() < 2 || !path.elementAt(0).isMoveTo())
+	if (path.isEmpty())
 		return;
 	if (text.isEmpty())
 		return;
@@ -106,16 +168,17 @@ void Text::addLabel(const QString &text, const QPainterPath &path,
 	if (textWidth > path.length())
 		return;
 
-	QList<QPainterPath> list(segments(path, textWidth, maxAngle,
-	  fm.averageCharWidth(), symbolSpacing, sceneRect()));
-	for (int i = 0; i < list.size(); i++) {
-		const QPainterPath &segment = list.at(i);
-		TextPathItem *pi = new TextPathItem(text, reverse(segment)
-		  ? segment.toReversed() : segment, font);
+	QPainterPath tp(textPath(path, textWidth, maxAngle, fm.averageCharWidth(),
+	  sceneRect()));
+	if (tp.isEmpty())
+		return;
+
+	TextPathItem *pi = new TextPathItem(text, reverse(tp) ? tp.toReversed()
+	  : tp, font);
 	addItem(pi);
 	if (!sceneRect().contains(pi->sceneBoundingRect())) {
 		delete pi;
-			continue;
+		return;
 	}
 
 	pi->setPen(pen);
@@ -123,5 +186,4 @@ void Text::addLabel(const QString &text, const QPainterPath &path,
 	QList<QGraphicsItem*> ci = collidingItems(pi);
 	for (int j = 0; j < ci.size(); j++)
 		ci[j]->setVisible(false);
-	}
 }

src/text.h

@@ -12,7 +12,7 @@ public:
 	void addLabel(const QString &text, const QPointF &pos, const QFont &font,
 	  const QPen &pen, qreal maxTextWidth);
 	void addLabel(const QString &text, const QPainterPath &path,
-	  const QFont &font, const QPen &pen, qreal maxAngle, qreal symbolSpacing);
+	  const QFont &font, const QPen &pen, qreal maxAngle);
 };
 
 #endif // TEXT_H

src/textitem.cpp

@@ -26,4 +26,7 @@ void TextItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 	painter->setFont(_font);
 	painter->setPen(_pen);
 	painter->drawText(_boundingRect, FLAGS, _text);
+
+	//painter->setPen(Qt::red);
+	//painter->drawRect(_boundingRect);
 }

src/textpathitem.cpp

@@ -22,15 +22,13 @@ void TextPathItem::paint(QPainter *painter,
 	QFontMetrics fm(_font);
 	int textWidth = fm.width(_text);
 
-	qreal factor = (textWidth) / _path.length();
+	qreal factor = (textWidth) / qMax(_path.length(), (qreal)textWidth);
 	qreal percent = (1.0 - factor) / 2.0;
 
 	painter->setFont(_font);
 	painter->setPen(_pen);
 
 	for (int i = 0; i < _text.size(); i++) {
-		Q_ASSERT(percent <= 1.0);
-
 		QPointF point = _path.pointAtPercent(percent);
 		qreal angle = _path.angleAtPercent(percent);
 
@@ -42,4 +40,7 @@ void TextPathItem::paint(QPainter *painter,
 		int width = fm.charWidth(_text, i);
 		percent += ((qreal)width / (qreal)textWidth) * factor;
 	}
+
+	//painter->setPen(Qt::red);
+	//painter->drawPath(_shape);
 }