From fe69280cc5e5c110b068b59e815e295b7b5f68b1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20T=C5=AFma?= <tumic@cbox.cz>
Date: Wed, 29 May 2019 18:27:11 +0200
Subject: [PATCH] Fixed broken zoom fit on IMG maps

---
 src/map/imgmap.cpp | 23 ++++++++++++++---------
 src/map/imgmap.h   |  1 +
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/map/imgmap.cpp b/src/map/imgmap.cpp
index fc8dc4aa..a16405b1 100644
--- a/src/map/imgmap.cpp
+++ b/src/map/imgmap.cpp
@@ -109,13 +109,13 @@ QRectF IMGMap::bounds()
 int IMGMap::zoomFit(const QSize &size, const RectC &rect)
 {
 	if (rect.isValid()) {
-		QPointF sc((rect.right() - rect.left()) / size.width(),
-		  (rect.top() - rect.bottom()) / size.height());
-		double resolution = qMax(qAbs(sc.x()), qAbs(sc.y()));
+		RectD pr(rect, _projection, 10);
 
 		_zoom = _zooms.min();
-		for (int i = _zooms.min(); i <= _zooms.max(); i++) {
-			if (360.0 / (1<<i) < resolution)
+		for (int i = _zooms.min() + 1; i <= _zooms.max(); i++) {
+			Transform t(transform(i));
+			QRectF r(t.proj2img(pr.topLeft()), t.proj2img(pr.bottomRight()));
+			if (size.width() < r.width() || size.height() < r.height())
 				break;
 			_zoom = i;
 		}
@@ -147,12 +147,17 @@ void IMGMap::setZoom(int zoom)
 	updateTransform();
 }
 
+Transform IMGMap::transform(int zoom) const
+{
+	double scale = (2.0 * M_PI * WGS84_RADIUS) / (1<<zoom);
+	PointD topLeft(_projection.ll2xy(_img.bounds().topLeft()));
+	return Transform(ReferencePoint(PointD(0, 0), topLeft),
+	  PointD(scale, scale));
+}
+
 void IMGMap::updateTransform()
 {
-	double scale = (2.0 * M_PI * WGS84_RADIUS) / (1<<_zoom);;
-	PointD topLeft(_projection.ll2xy(_img.bounds().topLeft()));
-	_transform = Transform(ReferencePoint(PointD(0, 0), topLeft),
-	  PointD(scale, scale));
+	_transform = transform(_zoom);
 }
 
 QPointF IMGMap::ll2xy(const Coordinates &c)
diff --git a/src/map/imgmap.h b/src/map/imgmap.h
index 0c46419e..1856a884 100644
--- a/src/map/imgmap.h
+++ b/src/map/imgmap.h
@@ -39,6 +39,7 @@ public:
 private:
 	friend class RasterTile;
 
+	Transform transform(int zoom) const;
 	void updateTransform();
 	void drawPolygons(QPainter *painter, QList<IMG::Poly> &polygons);
 	void drawLines(QPainter *painter, QList<IMG::Poly> &lines,