Added support for image scaling

+ improved text path items performance

src/pbf.cpp

@@ -114,7 +114,7 @@ static inline QPoint parameters(quint32 v1, quint32 v2)
 }
 
 static void drawFeature(const Feature &feature, Style *style, int styleLayer,
-  qreal factor, Tile &tile)
+  const QSizeF &factor, Tile &tile)
 {
 	if (!style->match(styleLayer, feature.tags()))
 		return;
@@ -133,7 +133,8 @@ static void drawFeature(const Feature &feature, Style *style, int styleLayer,
 				  feature.data()->geometry(i+2));
 				i += 2;
 				cursor += offset;
-				path.moveTo(QPointF(cursor) / factor);
+				path.moveTo(QPointF(cursor.x() * factor.width(),
+				  cursor.y() * factor.height()));
 			}
 		} else if (cmdId == LINE_TO) {
 			for (unsigned j = 0; j < cmdCount; j++) {
@@ -141,7 +142,8 @@ static void drawFeature(const Feature &feature, Style *style, int styleLayer,
 				  feature.data()->geometry(i+2));
 				i += 2;
 				cursor += offset;
-				path.lineTo(QPointF(cursor) / factor);
+				path.lineTo(QPointF(cursor.x() * factor.width(),
+				  cursor.y() * factor.height()));
 			}
 		} else if (cmdId == CLOSE_PATH) {
 			path.closeSubpath();
@@ -158,21 +160,23 @@ static void drawLayer(const Layer &layer, Style *style, int styleLayer,
 	if (layer.data()->version() > 2)
 		return;
 
-	qreal factor = layer.data()->extent() / (qreal)tile.size();
+	QSizeF factor(tile.size().width() / (qreal)layer.data()->extent(),
+	  tile.size().height() / (qreal)layer.data()->extent());
 
 	for (int i = 0; i < layer.features().size(); i++)
 		drawFeature(layer.features().at(i), style, styleLayer, factor, tile);
 }
 
-QImage PBF::image(const QByteArray &data, int zoom, Style *style, int size)
+bool PBF::render(const QByteArray &data, int zoom, Style *style, qreal scale,
+  QImage *image)
 {
 	vector_tile::Tile tile;
 	if (!tile.ParseFromArray(data.constData(), data.size())) {
 		qCritical() << "Invalid tile protocol buffer data";
-		return QImage();
+		return false;
 	}
 
-	Tile t(size);
+	Tile t(image, scale);
 
 	style->setZoom(zoom);
 	style->drawBackground(t);
@@ -196,5 +200,7 @@ QImage PBF::image(const QByteArray &data, int zoom, Style *style, int size)
 		drawLayer(*it, style, i, t);
 	}
 
-	return t.render();
+	t.render();
+
+	return true;
 }

src/pbf.h

@@ -8,7 +8,8 @@ class Style;
 
 namespace PBF
 {
-	QImage image(const QByteArray &data, int zoom, Style *style, int size);
+	bool render(const QByteArray &data, int zoom, Style *style, qreal scale,
+	  QImage *render);
 }
 
 #endif // PBF_H

src/pbfhandler.cpp

@@ -47,12 +47,10 @@ bool PBFHandler::canRead(QIODevice *device)
 bool PBFHandler::read(QImage *image)
 {
 	quint32 magic;
-	qint64 size = device()->peek((char*)&magic, sizeof(magic));
+	if (device()->peek((char*)&magic, sizeof(magic)) != sizeof(magic))
-	if (size != sizeof(magic))
 		return false;
 
 	QByteArray ba;
-
 	if (isGZIPPBF(magic))
 		ba = Gzip::uncompress(device()->readAll());
 	else if (isPlainPBF(magic))
@@ -62,14 +60,28 @@ bool PBFHandler::read(QImage *image)
 
 	bool ok;
 	int zoom = format().toInt(&ok);
-	*image = PBF::image(ba, ok ? zoom : -1, _style, TILE_SIZE);
 
-	return !image->isNull();
+	QSize size = _scaledSize.isValid()
+	  ? _scaledSize : QSize(TILE_SIZE, TILE_SIZE);
+	qreal scale = _scaledSize.isValid()
+	  ? qMax(_scaledSize.width() / TILE_SIZE, _scaledSize.height() / TILE_SIZE)
+	  : 1.0;
+	*image = QImage(size, QImage::Format_ARGB32);
+
+	return PBF::render(ba, ok ? zoom : -1, _style, scale, image);
 }
 
 bool PBFHandler::supportsOption(ImageOption option) const
 {
-	return (option == Size);
+	return (option == Size || option == ScaledSize);
+}
+
+
+void PBFHandler::setOption(QImageIOHandler::ImageOption option,
+  const QVariant &value)
+{
+	if (option == ScaledSize)
+		_scaledSize = value.toSize();
 }
 
 QVariant PBFHandler::option(ImageOption option) const

src/pbfhandler.h

@@ -4,6 +4,7 @@
 #include <QImageIOHandler>
 #include <QImage>
 #include <QVariant>
+#include <QSize>
 
 class Style;
 
@@ -19,11 +20,13 @@ public:
 	QByteArray name() const;
 	QVariant option(ImageOption option) const;
 	bool supportsOption(ImageOption option) const;
+	void setOption(QImageIOHandler::ImageOption option, const QVariant &value);
 
 	static bool canRead(QIODevice *device);
 
 private:
 	Style *_style;
+	QSize _scaledSize;
 };
 
 #endif // PBFHANDLER_H

src/style.cpp

@@ -473,7 +473,7 @@ void Style::drawFeature(int layer, const QPainterPath &path,
 
 void Style::drawBackground(Tile &tile)
 {
-	QRectF rect(0, 0, tile.size(), tile.size());
+	QRectF rect(QPointF(0, 0), tile.size());
 	QPainterPath path;
 	path.addRect(rect);
 

src/text.cpp

@@ -155,7 +155,15 @@ void Text::addLabel(const QString &text, const QPointF &pos, const QFont &font,
 	if (text.isEmpty())
 		return;
 
-	TextPointItem *ti = new TextPointItem(text, pos, font, maxTextWidth);
+	TextPointItem *ti;
+
+	if (_fontScale != 1.0) {
+		QFont scaledFont(font);
+		scaledFont.setPixelSize(font.pixelSize() * _fontScale);
+		ti = new TextPointItem(text, pos, scaledFont, maxTextWidth);
+	} else
+		ti = new TextPointItem(text, pos, font, maxTextWidth);
+
 	ti->setPen(pen);
 	addItem(ti);
 	QList<TextItem*> ci = collidingItems(ti);
@@ -171,19 +179,20 @@ void Text::addLabel(const QString &text, const QPainterPath &path,
 	if (text.isEmpty())
 		return;
 
-	QFontMetrics fm(font);
+	QFont scaledFont(font);
-	int textWidth = fm.width(text);
+	scaledFont.setPixelSize(font.pixelSize() * _fontScale);
 
+	int textWidth = text.size() * scaledFont.pixelSize() * 0.6;
 	if (textWidth > path.length())
 		return;
 
-	QPainterPath tp(textPath(path, textWidth, maxAngle, fm.averageCharWidth(),
+	QPainterPath tp(textPath(path, textWidth, maxAngle,
-	  _sceneRect));
+	  scaledFont.pixelSize() / 2, _sceneRect));
 	if (tp.isEmpty())
 		return;
 
 	TextPathItem *pi = new TextPathItem(text, reverse(tp) ? tp.toReversed()
-	  : tp, font);
+	  : tp, scaledFont);
 	if (!_sceneRect.contains(pi->boundingRect())) {
 		delete pi;
 		return;

src/text.h

@@ -6,7 +6,8 @@
 class Text
 {
 public:
-	Text(int size) : _sceneRect(QRectF(0, 0, size, size)) {}
+	Text(const QSize &size, qreal scale)
+	  : _sceneRect(QRectF(QPointF(0, 0), size)), _fontScale(scale) {}
 	~Text();
 
 	void render(QPainter *painter);
@@ -21,6 +22,7 @@ private:
 	QList<TextItem *> collidingItems(const TextItem *item) const;
 
 	QRectF _sceneRect;
+	qreal _fontScale;
 	QList<TextItem *> _items;
 };
 

src/textpathitem.cpp

@@ -6,9 +6,8 @@
 TextPathItem::TextPathItem(const QString &text, const QPainterPath &path,
   const QFont &font) : _text(text), _path(path), _font(font)
 {
-	QFontMetrics fm(font);
 	QPainterPathStroker s;
-	s.setWidth(fm.height());
+	s.setWidth(font.pixelSize());
 	s.setCapStyle(Qt::FlatCap);
 	_shape = s.createStroke(path).simplified();
 	_boundingRect = _shape.boundingRect();

src/tile.h

@@ -7,20 +7,17 @@
 
 class Tile {
 public:
-	Tile(int size) : _background(size, size, QImage::Format_ARGB32),
+	Tile(QImage *img, qreal scale)
-	  _text(size), _painter(&_background) {}
+	  : _size(img->size()), _text(img->size(), scale), _painter(img) {}
 
-	int size() const {return _background.width();}
+	QSize size() const {return _size;}
 	Text &text() {return _text;}
 	QPainter &painter() {return _painter;}
 
-	const QImage &render() {
+	void render() {_text.render(&_painter);}
-		_text.render(&painter());
-		return _background;
-	}
 
 private:
-	QImage _background;
+	QSize _size;
 	Text _text;
 	QPainter _painter;
 };