Use a dedicated graphics item for drawing the text instead a pixmap

pbfplugin.pro

@@ -18,7 +18,8 @@ HEADERS += src/pbfhandler.h \
     src/text.h \
     src/tile.h \
     src/function.h \
-    src/textpathitem.h
+    src/textpathitem.h \
+    src/textitem.h
 SOURCES += src/pbfplugin.cpp \
     src/pbfhandler.cpp \
     src/gzip.cpp \
@@ -27,7 +28,8 @@ SOURCES += src/pbfplugin.cpp \
     src/color.cpp \
     src/text.cpp \
     src/function.cpp \
-    src/textpathitem.cpp
+    src/textpathitem.cpp \
+    src/textitem.cpp
 
 LIBS += -lprotobuf-lite
 

src/text.cpp

@@ -2,6 +2,7 @@
 #include <QFontMetrics>
 #include <QPainter>
 #include "text.h"
+#include "textitem.h"
 #include "textpathitem.h"
 
 
@@ -51,27 +52,16 @@ void Text::addLabel(const QString &text, const QPointF &pos, const QFont &font,
 	if (text.isEmpty())
 		return;
 
-	QFontMetrics fm(font);
-	int limit = fm.width('M') * maxTextWidth;
-	int flags = Qt::AlignCenter | Qt::TextWordWrap | Qt::TextDontClip;
-
-	QRect br = fm.boundingRect(QRect(0, 0, limit, 0), flags, text);
-	if (!br.isValid())
+	TextItem *ti = new TextItem(text, pos, font, maxTextWidth);
+	addItem(ti);
+	if (!sceneRect().contains(ti->sceneBoundingRect())) {
+		delete ti;
 		return;
-	br.moveTo((pos - QPointF(br.width() / 2.0, br.height() / 2.0)).toPoint());
-	if (!sceneRect().contains(br))
-		return;
-	QPixmap pm(br.size());
-	pm.fill(Qt::transparent);
-	QPainter p(&pm);
-	p.setFont(font);
-	p.setPen(pen);
-	p.drawText(pm.rect(), flags, text);
+	}
 
-	QGraphicsPixmapItem *pi = addPixmap(pm);
-	pi->setPos(br.topLeft());
+	ti->setPen(pen);
 
-	QList<QGraphicsItem*> ci = collidingItems(pi);
+	QList<QGraphicsItem*> ci = collidingItems(ti);
 	for (int i = 0; i < ci.size(); i++)
 		ci[i]->setVisible(false);
 }
@@ -95,14 +85,14 @@ void Text::addLabel(const QString &text, const QPainterPath &path,
 		const QPainterPath &segment = list.at(i);
 		TextPathItem *pi = new TextPathItem(text, reverse(segment)
 		  ? segment.toReversed() : segment, font);
-		pi->setPen(pen);
 		addItem(pi);
-
 		if (!sceneRect().contains(pi->sceneBoundingRect())) {
 			delete pi;
 			continue;
 		}
 
+		pi->setPen(pen);
+
 		QList<QGraphicsItem*> ci = collidingItems(pi);
 		for (int j = 0; j < ci.size(); j++)
 			ci[j]->setVisible(false);

src/textitem.cpp

@@ -0,0 +1,29 @@
+#include  <QPainter>
+#include "textitem.h"
+
+
+#define FLAGS (Qt::AlignCenter | Qt::TextWordWrap | Qt::TextDontClip)
+
+TextItem::TextItem(const QString &text, const QPointF &pos, const QFont &font,
+  int maxTextWidth, QGraphicsItem *parent) : QGraphicsItem(parent), _text(text),
+  _font(font)
+{
+	QFontMetrics fm(font);
+	int limit = fm.width('M') * maxTextWidth;
+
+	QRect br = fm.boundingRect(QRect(0, 0, limit, 0), FLAGS, text);
+	Q_ASSERT(br.isValid());
+	setPos((pos - QPointF(br.width() / 2.0, br.height() / 2.0)).toPoint());
+	_boundingRect = QRectF(0, 0, br.width(), br.height());
+}
+
+void TextItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
+  QWidget *widget)
+{
+	Q_UNUSED(option);
+	Q_UNUSED(widget);
+
+	painter->setFont(_font);
+	painter->setPen(_pen);
+	painter->drawText(_boundingRect, FLAGS, _text);
+}

src/textitem.h

@@ -0,0 +1,28 @@
+#ifndef TEXTITEM_H
+#define TEXTITEM_H
+
+#include <QGraphicsItem>
+#include <QPen>
+#include <QFont>
+#include <QString>
+
+class TextItem : public QGraphicsItem
+{
+public:
+	TextItem(const QString &text, const QPointF &pos, const QFont &font,
+	  int maxTextWidth, QGraphicsItem *parent = 0);
+
+	QRectF boundingRect() const {return _boundingRect;}
+	void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
+	  QWidget *widget);
+
+	void setPen(const QPen &pen) {_pen = pen;}
+
+private:
+	QString _text;
+	QRectF _boundingRect;
+	QFont _font;
+	QPen _pen;
+};
+
+#endif // TEXTITEM_H