From d794de581802b05360d9afd5cf4d4efa97ac88d0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20T=C5=AFma?= <tumic@cbox.cz>
Date: Mon, 3 Apr 2023 23:53:57 +0200
Subject: [PATCH] Added support for curved lines

---
 src/map/mapsforge/rastertile.cpp | 27 +++++++++++++++++++++------
 src/map/mapsforge/rastertile.h   |  2 +-
 src/map/mapsforge/style.cpp      |  5 +++++
 src/map/mapsforge/style.h        |  5 +++--
 4 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/src/map/mapsforge/rastertile.cpp b/src/map/mapsforge/rastertile.cpp
index c6dd89b5..780064ee 100644
--- a/src/map/mapsforge/rastertile.cpp
+++ b/src/map/mapsforge/rastertile.cpp
@@ -171,7 +171,7 @@ void RasterTile::processAreaLabels(QList<TextItem*> &textItems)
 			continue;
 
 		if (!path.path.elementCount())
-			path.path = painterPath(path.poly);
+			path.path = painterPath(path.poly, false);
 
 		const QImage *img = si ? &si->img() : 0;
 		const QFont *font = ti ? &ti->font() : 0;
@@ -232,16 +232,31 @@ void RasterTile::drawTextItems(QPainter *painter,
 		textItems.at(i)->paint(painter);
 }
 
-QPainterPath RasterTile::painterPath(const Polygon &polygon) const
+QPainterPath RasterTile::painterPath(const Polygon &polygon, bool curve) const
 {
 	QPainterPath path;
 
 	for (int i = 0; i < polygon.size(); i++) {
 		const QVector<Coordinates> &subpath = polygon.at(i);
 
-		path.moveTo(ll2xy(subpath.first()));
-		for (int j = 1; j < subpath.size(); j++)
-			path.lineTo(ll2xy(subpath.at(j)));
+		if (curve) {
+			QPointF p1(ll2xy(subpath.first()));
+			QPointF p2(0, 0);
+			QPointF p3(0, 0);
+
+			path.moveTo(p1);
+			for (int j = 1; j < subpath.size(); j++) {
+				p3 = ll2xy(subpath.at(j));
+				p2 = QPointF((p1.x() + p3.x()) / 2.0, (p1.y() + p3.y()) / 2.0);
+				path.quadTo(p1, p2);
+				p1 = p3;
+			}
+			path.quadTo(p2, p3);
+		} else {
+			path.moveTo(ll2xy(subpath.first()));
+			for (int j = 1; j < subpath.size(); j++)
+				path.lineTo(ll2xy(subpath.at(j)));
+		}
 	}
 
 	return path;
@@ -300,7 +315,7 @@ void RasterTile::drawPaths(QPainter *painter)
 		}
 
 		if (!is.path()->path.elementCount())
-			is.path()->path = painterPath(is.path()->poly);
+			is.path()->path = painterPath(is.path()->poly, ri->curve());
 
 		if (ri->area()) {
 			lp.setPen(ri->pen(_zoom));
diff --git a/src/map/mapsforge/rastertile.h b/src/map/mapsforge/rastertile.h
index e9185f85..0cdb97d0 100644
--- a/src/map/mapsforge/rastertile.h
+++ b/src/map/mapsforge/rastertile.h
@@ -76,7 +76,7 @@ private:
 	void processPointLabels(QList<TextItem*> &textItems);
 	void processAreaLabels(QList<TextItem*> &textItems);
 	void processLineLabels(QList<TextItem*> &textItems);
-	QPainterPath painterPath(const Polygon &polygon) const;
+	QPainterPath painterPath(const Polygon &polygon, bool curve) const;
 	void drawTextItems(QPainter *painter, const QList<TextItem*> &textItems);
 	void drawPaths(QPainter *painter);
 
diff --git a/src/map/mapsforge/style.cpp b/src/map/mapsforge/style.cpp
index 31bc90a1..8973ce3f 100644
--- a/src/map/mapsforge/style.cpp
+++ b/src/map/mapsforge/style.cpp
@@ -169,6 +169,11 @@ void Style::line(QXmlStreamReader &reader, const Rule &rule)
 		else if (join == "bevel")
 			ri._strokeJoin = Qt::BevelJoin;
 	}
+	if (attr.hasAttribute("curve")) {
+		QString curve(attr.value("curve").toString());
+		if (curve == "cubic")
+			ri._curve = true;
+	}
 
 	_paths.append(ri);
 
diff --git a/src/map/mapsforge/style.h b/src/map/mapsforge/style.h
index 06b2bd72..392dfe2b 100644
--- a/src/map/mapsforge/style.h
+++ b/src/map/mapsforge/style.h
@@ -163,12 +163,13 @@ public:
 	public:
 		PathRender(const Rule &rule, int zOrder) : Render(rule),
 		  _zOrder(zOrder), _strokeWidth(0), _strokeCap(Qt::RoundCap),
-		  _strokeJoin(Qt::RoundJoin), _area(false) {}
+		  _strokeJoin(Qt::RoundJoin), _area(false), _curve(false) {}
 
 		int zOrder() const {return _zOrder;}
 		QPen pen(int zoom) const;
 		QBrush brush() const;
 		bool area() const {return _area;}
+		bool curve() const {return _curve;}
 
 	private:
 		friend class Style;
@@ -180,7 +181,7 @@ public:
 		Qt::PenCapStyle _strokeCap;
 		Qt::PenJoinStyle _strokeJoin;
 		QImage _fillImage;
-		bool _area;
+		bool _area, _curve;
 	};
 
 	class TextRender : public Render