From 630a5cea838c19282f3dcafae64af5a83c01bc7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20T=C5=AFma?= <tumic@cbox.cz>
Date: Sat, 17 Oct 2020 14:26:59 +0200
Subject: [PATCH] Improved polygon labels layout logic

---
 src/map/IMG/rastertile.cpp    | 30 +++++++++++++++++++++++++++---
 src/map/IMG/textitem.h        |  5 +++++
 src/map/IMG/textpathitem.cpp  |  2 +-
 src/map/IMG/textpathitem.h    |  3 +--
 src/map/IMG/textpointitem.cpp |  2 +-
 src/map/IMG/textpointitem.h   |  3 +--
 6 files changed, 36 insertions(+), 9 deletions(-)

diff --git a/src/map/IMG/rastertile.cpp b/src/map/IMG/rastertile.cpp
index 3bf573b7..3a0acbce 100644
--- a/src/map/IMG/rastertile.cpp
+++ b/src/map/IMG/rastertile.cpp
@@ -237,10 +237,27 @@ void RasterTile::drawTextItems(QPainter *painter,
 		textItems.at(i)->paint(painter);
 }
 
+static void removeDuplicitLabel(QList<TextItem *> &labels, const QString &text,
+  const QRectF &tileRect)
+{
+	for (int j = 0; j < labels.size(); j++) {
+		TextItem *item = labels.at(j);
+		if (tileRect.contains(item->boundingRect()) && *(item->text()) == text) {
+			labels.removeOne(item);
+			return;
+		}
+	}
+}
+
 void RasterTile::processPolygons(QList<TextItem*> &textItems)
 {
+	QRectF tileRect(_xy, _img.size());
+	QSet<QString> set;
+	QList<TextItem *> labels;
+
 	for (int i = 0; i < _polygons.size(); i++) {
 		MapData::Poly &poly = _polygons[i];
+		bool exists = set.contains(poly.label.text());
 
 		if (poly.label.text().isEmpty())
 			continue;
@@ -253,12 +270,19 @@ void RasterTile::processPolygons(QList<TextItem*> &textItems)
 			  centroid(poly.points).toPoint(), &poly.label.text(),
 			  poiFont(), 0, &style.brush().color());
 			if (item->isValid() && !item->collides(textItems)
-			  && rectNearPolygon(poly.points, item->boundingRect()))
-				textItems.append(item);
-			else
+			  && !(exists && tileRect.contains(item->boundingRect()))
+			  && rectNearPolygon(poly.points, item->boundingRect())) {
+				if (exists)
+					removeDuplicitLabel(labels, poly.label.text(), tileRect);
+				else
+					set.insert(poly.label.text());
+				labels.append(item);
+			} else
 				delete item;
 		}
 	}
+
+	textItems.append(labels);
 }
 
 void RasterTile::processLines(QList<TextItem*> &textItems)
diff --git a/src/map/IMG/textitem.h b/src/map/IMG/textitem.h
index e3121e7b..2baca50e 100644
--- a/src/map/IMG/textitem.h
+++ b/src/map/IMG/textitem.h
@@ -10,13 +10,18 @@ class QPainter;
 class TextItem
 {
 public:
+	TextItem(const QString *text) : _text(text) {}
 	virtual ~TextItem() {}
 
 	virtual QPainterPath shape() const = 0;
 	virtual QRectF boundingRect() const = 0;
 	virtual void paint(QPainter *painter) const = 0;
 
+	const QString *text() const {return _text;}
 	bool collides(const QList<TextItem*> &list) const;
+
+protected:
+	const QString *_text;
 };
 
 #endif // TEXTITEM_H
diff --git a/src/map/IMG/textpathitem.cpp b/src/map/IMG/textpathitem.cpp
index 504b45dd..6af30ef3 100644
--- a/src/map/IMG/textpathitem.cpp
+++ b/src/map/IMG/textpathitem.cpp
@@ -137,7 +137,7 @@ static bool reverse(const QPainterPath &path)
 
 TextPathItem::TextPathItem(const QPolygonF &line, const QString *label,
   const QRect &tileRect, const QFont *font, const QColor *color)
-  : _text(label), _font(font), _color(color)
+  : TextItem(label), _font(font), _color(color)
 {
 	qreal cw = font->pixelSize() * 0.7;
 	qreal textWidth = _text->size() * cw;
diff --git a/src/map/IMG/textpathitem.h b/src/map/IMG/textpathitem.h
index cc33cd1a..3ef7a1e4 100644
--- a/src/map/IMG/textpathitem.h
+++ b/src/map/IMG/textpathitem.h
@@ -8,7 +8,7 @@
 class TextPathItem : public TextItem
 {
 public:
-	TextPathItem() : _text(0), _font(0), _color(0) {}
+	TextPathItem() : TextItem(0), _font(0), _color(0) {}
 	TextPathItem(const QPolygonF &line, const QString *label,
 	  const QRect &tileRect, const QFont *font, const QColor *color);
 
@@ -19,7 +19,6 @@ public:
 	void paint(QPainter *painter) const;
 
 private:
-	const QString *_text;
 	const QFont *_font;
 	const QColor *_color;
 	QPainterPath _path;
diff --git a/src/map/IMG/textpointitem.cpp b/src/map/IMG/textpointitem.cpp
index dfed98e3..9d90c281 100644
--- a/src/map/IMG/textpointitem.cpp
+++ b/src/map/IMG/textpointitem.cpp
@@ -17,7 +17,7 @@ static void expand(QRect &rect, int width)
 
 TextPointItem::TextPointItem(const QPoint &point, const QString *text,
   const QFont *font, const QImage *img, const QColor *color,
-  const QColor *bgColor) : _text(font ? text : 0), _font(font), _img(img),
+  const QColor *bgColor) : TextItem(font ? text : 0), _font(font), _img(img),
   _color(color), _bgColor(bgColor)
 {
 	if (_text) {
diff --git a/src/map/IMG/textpointitem.h b/src/map/IMG/textpointitem.h
index c4190a7d..7aa9b5ca 100644
--- a/src/map/IMG/textpointitem.h
+++ b/src/map/IMG/textpointitem.h
@@ -14,7 +14,7 @@ class QColor;
 class TextPointItem : public TextItem
 {
 public:
-	TextPointItem() : _text(0), _font(0), _img(0) {}
+	TextPointItem() : TextItem(0), _font(0), _img(0) {}
 	TextPointItem(const QPoint &point, const QString *text, const QFont *font,
 	  const QImage *img, const QColor *color, const QColor *bgColor = 0);
 
@@ -27,7 +27,6 @@ public:
 	void setPos(const QPoint &point);
 
 private:
-	const QString *_text;
 	const QFont *_font;
 	const QImage *_img;
 	const QColor *_color, *_bgColor;