diff --git a/src/GUI/axisitem.cpp b/src/GUI/axisitem.cpp
index 98c5819d..375e8ffe 100644
--- a/src/GUI/axisitem.cpp
+++ b/src/GUI/axisitem.cpp
@@ -11,23 +11,28 @@
 #define XTICKS      15
 #define YTICKS      10
 
-struct Label {
-	double min;
-	double max;
-	double d;
+class Ticks
+{
+public:
+	Ticks(double min, double max, int count);
+
+	int count() const {return ((int)((_max - _min) / _d)) + 1;}
+	double val(int i) const {return _min + i * _d;}
+	double min() const {return _min;}
+	double max() const {return _max;}
+
+private:
+	double _min;
+	double _max;
+	double _d;
 };
 
-static struct Label label(double min, double max, int ticks)
+Ticks::Ticks(double min, double max, int count)
 {
-	double range;
-	struct Label l;
-
-	range = niceNum(max - min, 0);
-	l.d = niceNum(range / ticks, 1);
-	l.min = ceil(min / l.d) * l.d;
-	l.max = floor(max / l.d) * l.d;
-
-	return l;
+	double range = niceNum(max - min, 0);
+	_d = niceNum(range / count, 1);
+	_min = ceil(min / _d) * _d;
+	_max = floor(max / _d) * _d;
 }
 
 
@@ -48,6 +53,16 @@ void AxisItem::setRange(const RangeF &range)
 {
 	prepareGeometryChange();
 	_range = range;
+
+	QFontMetrics fm(_font);
+	Ticks ticks(_range.min(), _range.max(), (_type == X) ? XTICKS : YTICKS);
+	_ticks = QVector<Tick>(ticks.count());
+	for (int i = 0; i < ticks.count(); i++) {
+		Tick &t = _ticks[i];
+		t.value = ticks.val(i);
+		t.boundingBox = fm.tightBoundingRect(QString::number(t.value));
+	}
+
 	updateBoundingRect();
 	update();
 }
@@ -63,7 +78,9 @@ void AxisItem::setSize(qreal size)
 void AxisItem::setLabel(const QString& label)
 {
 	prepareGeometryChange();
+	QFontMetrics fm(_font);
 	_label = label;
+	_labelBB = fm.tightBoundingRect(label);
 	updateBoundingRect();
 	update();
 }
@@ -71,31 +88,18 @@ void AxisItem::setLabel(const QString& label)
 void AxisItem::updateBoundingRect()
 {
 	QFontMetrics fm(_font);
-	QRect ss, es, ls;
-	struct Label l;
-
-
-	l = label(_range.min(), _range.max(), (_type == X) ? XTICKS : YTICKS);
-	es = fm.tightBoundingRect(QString::number(l.max));
-	ss = fm.tightBoundingRect(QString::number(l.min));
-	ls = fm.tightBoundingRect(_label);
+	QRect es = _ticks.isEmpty() ? QRect() : _ticks.last().boundingBox;
+	QRect ss = _ticks.isEmpty() ? QRect() : _ticks.first().boundingBox;
+	QRect ls(_labelBB);
 
 	if (_type == X) {
-		_boundingRect = QRectF(-ss.width()/2, -TICK/2,
-		_size + es.width()/2 + ss.width()/2,
-		ls.height() + es.height() - fm.descent() + TICK + 2*PADDING + 1);
+		_boundingRect = QRectF(-ss.width()/2, -TICK/2, _size + es.width()/2
+		  + ss.width()/2, ls.height() + es.height() - fm.descent() + TICK
+		  + 2*PADDING + 1);
 	} else {
 		int mtw = 0;
-		QRect ts;
-		qreal val;
-
-		for (int i = 0; i < ((l.max - l.min) / l.d) + 1; i++) {
-			val = l.min + i * l.d;
-			QString str = QString::number(val);
-			ts = fm.tightBoundingRect(str);
-			mtw = qMax(ts.width(), mtw);
-		}
-
+		for (int i = 0; i < _ticks.count(); i++)
+			mtw = qMax(_ticks.at(i).boundingBox.width(), mtw);
 		_boundingRect = QRectF(-(ls.height() + mtw + 2*PADDING + TICK/2),
 		  -(_size + es.height()/2 + fm.descent()), ls.height() + mtw + 2*PADDING
 		  + TICK, _size + es.height()/2 + fm.descent() + ss.height()/2);
@@ -108,8 +112,6 @@ void AxisItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 	Q_UNUSED(option);
 	Q_UNUSED(widget);
 	QFontMetrics fm(_font);
-	QRect ls(fm.tightBoundingRect(_label));
-	qreal range = _range.size();
 	QRect ts;
 
 
@@ -120,40 +122,39 @@ void AxisItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 	if (_type == X) {
 		painter->drawLine(0, 0, _size, 0);
 
-		Label l = label(_range.min(), _range.max(), XTICKS);
-		for (int i = 0; i < ((l.max - l.min) / l.d) + 1; i++) {
-			qreal val = l.min + i * l.d;
-			QString str = QString::number(val);
+		for (int i = 0; i < _ticks.count(); i++) {
+			qreal val = _ticks.at(i).value;
+			ts = _ticks.at(i).boundingBox;
 
-			painter->drawLine((_size/range) * (val - _range.min()), TICK/2,
-			  (_size/range) * (val - _range.min()), -TICK/2);
-			ts = fm.tightBoundingRect(str);
-			painter->drawText(((_size/range) * (val - _range.min()))
-			  - (ts.width()/2), ts.height() + TICK/2 + PADDING, str);
+			painter->drawLine((_size/_range.size()) * (val - _range.min()),
+			  TICK/2, (_size/_range.size()) * (val - _range.min()), -TICK/2);
+			painter->drawText(((_size/_range.size()) * (val - _range.min()))
+			  - (ts.width()/2), ts.height() + TICK/2 + PADDING,
+			  QString::number(val));
 		}
 
-		painter->drawText(_size/2 - ls.width()/2, ls.height() + ts.height()
-		  - 2*fm.descent() + TICK/2 + 2*PADDING, _label);
+		painter->drawText(_size/2 - _labelBB.width()/2, _labelBB.height()
+		  + ts.height() - 2*fm.descent() + TICK/2 + 2*PADDING, _label);
 	} else {
 		painter->drawLine(0, 0, 0, -_size);
 
-		Label l = label(_range.min(), _range.max(), YTICKS);
 		int mtw = 0;
-		for (int i = 0; i < ((l.max - l.min) / l.d) + 1; i++) {
-			qreal val = l.min + i * l.d;
-			QString str = QString::number(val);
-
-			painter->drawLine(TICK/2, -((_size/range) * (val - _range.min())),
-			  -TICK/2, -((_size/range) * (val - _range.min())));
-			ts = fm.tightBoundingRect(str);
+		for (int i = 0; i < _ticks.count(); i++) {
+			qreal val = _ticks.at(i).value;
+			ts = _ticks.at(i).boundingBox;
 			mtw = qMax(ts.width(), mtw);
-			painter->drawText(-(ts.width() + PADDING + TICK/2), -((_size/range)
-			  * (val - _range.min())) + (ts.height()/2), str);
+
+			painter->drawLine(TICK/2, -((_size/_range.size())
+			  * (val - _range.min())), -TICK/2, -((_size/_range.size())
+			  * (val - _range.min())));
+			painter->drawText(-(ts.width() + PADDING + TICK/2),
+			  -((_size/_range.size()) * (val - _range.min())) + (ts.height()/2),
+			  QString::number(val));
 		}
 
 		painter->rotate(-90);
-		painter->drawText(_size/2 - ls.width()/2, -(mtw + 2*PADDING + TICK/2),
-		  _label);
+		painter->drawText(_size/2 - _labelBB.width()/2, -(mtw + 2*PADDING
+		  + TICK/2), _label);
 		painter->rotate(90);
 	}
 
@@ -165,46 +166,28 @@ void AxisItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 
 QSizeF AxisItem::margin() const
 {
-	QFont font;
-	font.setPixelSize(FONT_SIZE);
-	QFontMetrics fm(font);
-	QRect ss, es, ls;
-	struct Label l;
-
-
-	l = label(_range.min(), _range.max(), (_type == X) ? XTICKS : YTICKS);
-	es = fm.tightBoundingRect(QString::number(l.max));
-	ss = fm.tightBoundingRect(QString::number(l.min));
-	ls = fm.tightBoundingRect(_label);
+	QFontMetrics fm(_font);
+	QRect es = _ticks.isEmpty() ? QRect() : _ticks.last().boundingBox;
 
 	if (_type == X) {
-		return QSizeF(es.width()/2,
-		  ls.height() + es.height() - fm.descent() + TICK/2 + 2*PADDING);
+		return QSizeF(es.width()/2, _labelBB.height() + es.height()
+		  - fm.descent() + TICK/2 + 2*PADDING);
 	} else {
 		int mtw = 0;
-		QRect ts;
-		qreal val;
+		for (int i = 0; i < _ticks.count(); i++)
+			mtw = qMax(_ticks.at(i).boundingBox.width(), mtw);
 
-		for (int i = 0; i < ((l.max - l.min) / l.d) + 1; i++) {
-			val = l.min + i * l.d;
-			QString str = QString::number(val);
-			ts = fm.tightBoundingRect(str);
-			mtw = qMax(ts.width(), mtw);
-		}
-
-		return QSizeF(ls.height() -fm.descent() + mtw + 2*PADDING
+		return QSizeF(_labelBB.height() -fm.descent() + mtw + 2*PADDING
 		  + TICK/2, es.height()/2 + fm.descent());
 	}
 }
 
 QList<qreal> AxisItem::ticks() const
 {
-	struct Label l;
 	QList<qreal> list;
 
-	l = label(_range.min(), _range.max(), (_type == X) ? XTICKS : YTICKS);
-	for (int i = 0; i < ((l.max - l.min) / l.d) + 1; i++)
-		list.append(((_size/_range.size()) * ((l.min + i * l.d)
+	for (int i = 0; i < _ticks.count(); i++)
+		list.append(((_size/_range.size()) * (_ticks.at(i).value
 		  - _range.min())));
 
 	return list;
diff --git a/src/GUI/axisitem.h b/src/GUI/axisitem.h
index c1f94bec..f72cbe96 100644
--- a/src/GUI/axisitem.h
+++ b/src/GUI/axisitem.h
@@ -2,6 +2,7 @@
 #define AXISITEM_H
 
 #include <QGraphicsItem>
+#include <QVector>
 #include "common/range.h"
 
 class AxisItem : public QGraphicsItem
@@ -23,12 +24,19 @@ public:
 	QList<qreal> ticks() const;
 
 private:
+	struct Tick {
+		double value;
+		QRect boundingBox;
+	};
+
 	void updateBoundingRect();
 
 	Type _type;
 	RangeF _range;
 	qreal _size;
 	QString _label;
+	QRect _labelBB;
+	QVector<Tick> _ticks;
 	QRectF _boundingRect;
 	QFont _font;
 };
diff --git a/src/GUI/scaleitem.cpp b/src/GUI/scaleitem.cpp
index 11031b6f..94f0188c 100644
--- a/src/GUI/scaleitem.cpp
+++ b/src/GUI/scaleitem.cpp
@@ -26,20 +26,6 @@ ScaleItem::ScaleItem(QGraphicsItem *parent) : QGraphicsItem(parent)
 #endif // Q_OS_MAC
 }
 
-void ScaleItem::updateBoundingRect()
-{
-	QFontMetrics fm(_font);
-	QRect ss, es, us;
-
-	ss = fm.tightBoundingRect(QString::number(0));
-	es = fm.tightBoundingRect(QString::number(_length * SEGMENTS));
-	us = fm.tightBoundingRect(units());
-
-	_boundingRect = QRectF(-ss.width()/2, 0, _width * SEGMENTS + ss.width()/2
-	  + qMax(us.width() + PADDING, es.width()/2) + 1, SCALE_HEIGHT + PADDING
-	  + ss.height() + 2*fm.descent());
-}
-
 void ScaleItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
   QWidget *widget)
 {
@@ -53,13 +39,13 @@ void ScaleItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 	painter->setFont(_font);
 	painter->setPen(QPen(Qt::black, BORDER_WIDTH));
 
-	for (int i = 0; i <= SEGMENTS; i++) {
-		QString label = QString::number(_length * i);
-		br = fm.tightBoundingRect(label);
-		painter->drawText(_width * i - br.width()/2, br.height() + 1, label);
+	for (int i = 0; i < _ticks.size(); i++) {
+		br = _ticks.at(i).boundingBox;
+		painter->drawText(_width * i - br.width()/2, br.height() + 1,
+		  QString::number(_ticks.at(i).value));
 	}
 	painter->drawText(_width * SEGMENTS + PADDING, SCALE_HEIGHT + PADDING
-	  + br.height() + fm.descent(), units());
+	  + br.height() + fm.descent(), _unitsStr);
 
 	painter->drawRect(QRectF(0, br.height() + PADDING, SEGMENTS * _width,
 	  SCALE_HEIGHT));
@@ -73,19 +59,6 @@ void ScaleItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 */
 }
 
-QString ScaleItem::units() const
-{
-	if (_units == Imperial)
-		return _scale ? qApp->translate("ScaleItem", "mi")
-		  : qApp->translate("ScaleItem", "ft");
-	else if (_units == Nautical)
-		return _scale ? qApp->translate("ScaleItem", "nmi")
-		  : qApp->translate("ScaleItem", "ft");
-	else
-		return _scale ? qApp->translate("ScaleItem", "km")
-		  : qApp->translate("ScaleItem", "m");
-}
-
 void ScaleItem::computeScale()
 {
 	qreal res = _res * pow(2, -_digitalZoom);
@@ -123,21 +96,50 @@ void ScaleItem::computeScale()
 	}
 }
 
+void ScaleItem::updateCache()
+{
+	QFontMetrics fm(_font);
+
+	_ticks = QVector<Tick>(SEGMENTS + 1);
+	for (int i = 0; i < _ticks.size(); i++) {
+		Tick &t = _ticks[i];
+		t.value = _length * i;
+		t.boundingBox = fm.tightBoundingRect(QString::number(t.value));
+	}
+
+	if (_units == Imperial)
+		_unitsStr = _scale ? qApp->translate("ScaleItem", "mi")
+		  : qApp->translate("ScaleItem", "ft");
+	else if (_units == Nautical)
+		_unitsStr = _scale ? qApp->translate("ScaleItem", "nmi")
+		  : qApp->translate("ScaleItem", "ft");
+	else
+		_unitsStr = _scale ? qApp->translate("ScaleItem", "km")
+		  : qApp->translate("ScaleItem", "m");
+	_unitsBB = fm.tightBoundingRect(_unitsStr);
+
+	QRect ss = _ticks.isEmpty() ? QRect() : _ticks.first().boundingBox;
+	QRect es = _ticks.isEmpty() ? QRect() : _ticks.last().boundingBox;
+	_boundingRect = QRectF(-ss.width()/2, 0, _width * SEGMENTS + ss.width()/2
+	  + qMax(_unitsBB.width() + PADDING, es.width()/2) + 1, SCALE_HEIGHT
+	  + PADDING + ss.height() + 2*fm.descent());
+}
+
 void ScaleItem::setResolution(qreal res)
 {
 	prepareGeometryChange();
 	_res = res;
 	computeScale();
-	updateBoundingRect();
+	updateCache();
 	update();
 }
 
-void ScaleItem::setUnits(enum Units units)
+void ScaleItem::setUnits(Units units)
 {
 	prepareGeometryChange();
 	_units = units;
 	computeScale();
-	updateBoundingRect();
+	updateCache();
 	update();
 }
 
@@ -146,7 +148,7 @@ void ScaleItem::setDigitalZoom(qreal zoom)
 	prepareGeometryChange();
 	_digitalZoom = zoom;
 	computeScale();
-	updateBoundingRect();
+	updateCache();
 	update();
 
 	setScale(pow(2, -_digitalZoom));
diff --git a/src/GUI/scaleitem.h b/src/GUI/scaleitem.h
index 3c3ab11d..53b27287 100644
--- a/src/GUI/scaleitem.h
+++ b/src/GUI/scaleitem.h
@@ -14,13 +14,17 @@ public:
 	  QWidget *widget);
 
 	void setResolution(qreal res);
-	void setUnits(enum Units units);
+	void setUnits(Units units);
 	void setDigitalZoom(qreal zoom);
 
 private:
-	void updateBoundingRect();
+	struct Tick {
+		double value;
+		QRect boundingBox;
+	};
+
 	void computeScale();
-	QString units() const;
+	void updateCache();
 
 	qreal _res;
 	qreal _width;
@@ -30,6 +34,9 @@ private:
 	qreal _digitalZoom;
 	QRectF _boundingRect;
 	QFont _font;
+	QVector<Tick> _ticks;
+	QRect _unitsBB;
+	QString _unitsStr;
 };
 
 #endif // SCALEITEM_H