profile: add width() function to DiveCartesian axis

To properly layout the profile we need to know the expected space
required by the vertical axes. In the general case, format the
the text "999". For the partial-pressure-axis, use "0.99".

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

profile-widget/divecartesianaxis.cpp

@@ -8,6 +8,8 @@
 #include "profile-widget/divelineitem.h"
 #include "profile-widget/profilescene.h"
 
+static const double labelSpace = 2.0; // space between label and ticks
+
 QPen DiveCartesianAxis::gridPen() const
 {
 	QPen pen;
@@ -117,6 +119,18 @@ void emptyList(QList<T *> &list, int steps, int speed)
 	}
 }
 
+double DiveCartesianAxis::textWidth(const QString &s) const
+{
+	QFont fnt = DiveTextItem::getFont(dpr, labelScale);
+	QFontMetrics fm(fnt);
+	return fm.size(Qt::TextSingleLine, s).width() + labelSpace * dpr;
+}
+
+double DiveCartesianAxis::width() const
+{
+	return textWidth("999");
+}
+
 void DiveCartesianAxis::updateTicks(int animSpeed, color_index_t color)
 {
 	if (!changed && !printMode)
@@ -401,3 +415,8 @@ void PartialGasPressureAxis::update(int animSpeed)
 	setTickInterval(pp > 4 ? 0.5 : 0.25);
 	updateTicks(animSpeed);
 }
+
+double PartialGasPressureAxis::width() const
+{
+	return textWidth(textForValue(0.99));
+}

profile-widget/divecartesianaxis.h

@@ -49,6 +49,7 @@ public:
 	void setLineSize(qreal lineSize);
 	void setLine(const QLineF& line);
 	virtual void updateTicks(int animSpeed, color_index_t color = TIME_GRID);
+	double width() const;
 
 signals:
 	void sizeChanged();
@@ -57,6 +58,7 @@ protected:
 	ProfileScene &scene;
 	virtual QString textForValue(double value) const;
 	virtual QColor colorForValue(double value) const;
+	double textWidth(const QString &s) const;
 	Orientation orientation;
 	QList<DiveTextItem *> labels;
 	QList<DiveLineItem *> lines;
@@ -105,6 +107,7 @@ class PartialGasPressureAxis : public DiveCartesianAxis {
 public:
 	PartialGasPressureAxis(const DivePlotDataModel &model, double dpr, bool printMode, ProfileScene &scene);
 	void update(int animSpeed);
+	double width() const;
 private:
 	const DivePlotDataModel &model;
 };

profile-widget/divetextitem.cpp

@@ -59,15 +59,11 @@ const QString &DiveTextItem::text()
 	return internalText;
 }
 
-void DiveTextItem::updateText()
+QFont DiveTextItem::getFont(double dpr, double scale)
 {
-	double size;
-	if (internalText.isEmpty()) {
-		return;
-	}
-
 	QFont fnt(qApp->font());
-	if ((size = fnt.pixelSize()) > 0) {
+	double size = fnt.pixelSize();
+	if (size > 0) {
 		// set in pixels - so the scale factor may not make a difference if it's too close to 1
 		size *= scale * dpr;
 		fnt.setPixelSize(lrint(size));
@@ -76,6 +72,15 @@ void DiveTextItem::updateText()
 		size *= scale * dpr;
 		fnt.setPointSizeF(size);
 	}
+	return fnt;
+}
+
+void DiveTextItem::updateText()
+{
+	if (internalText.isEmpty())
+		return;
+
+	QFont fnt = getFont(dpr, scale);
 	QFontMetrics fm(fnt);
 
 	QPainterPath textPath;

profile-widget/divetextitem.h

@@ -3,6 +3,7 @@
 #define DIVETEXTITEM_H
 
 #include <QObject>
+#include <QFont>
 #include <QGraphicsItemGroup>
 
 class QBrush;
@@ -20,6 +21,7 @@ public:
 	void setBrush(const QBrush &brush);
 	const QString &text();
 	void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
+	static QFont getFont(double dpr, double scale);
 
 private:
 	void updateText();