try to fix profile scaling

Different approach here:

- profile gets a bit higher, this was requested on the mailinglist, and
  seems to behave much better with the painted profile, we'd otherwise
  get it magically clipped on the right hand side.
- Make the scaling dpi aware, this fixes scaling for me on the Nexus7, I
  haven't been able to test it properly on other devices, so this needs
  some more testing. The result is visually quite close to what we can
  do, although I'm still getting a somewhat larger margin on the right.
  To get at the devicePixelRatio without too much custom code, I've
  added a property to the QMLProfile to retrieve it from the theme engine.

Signed-off-by: Sebastian Kügler <sebas@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-mobile/qml/DiveDetailsView.qml

@@ -28,7 +28,6 @@ Item {
 	GridLayout {
 		id: mainLayout
 		anchors {
-		    //fill: parent
 		    top: parent.top
 		    left: parent.left
 		    right: parent.right
@@ -118,9 +117,11 @@ Item {
 		QMLProfile {
 			id: qmlProfile
 			Layout.fillWidth: true
-			Layout.minimumHeight: Layout.preferredHeight
+			Layout.preferredHeight: Layout.minimumHeight
-			Layout.preferredHeight: width * 0.66
+			Layout.minimumHeight: width * 0.75
 			Layout.columnSpan: 4
+			clip: false
+			devicePixelRatio: MobileComponents.Units.devicePixelRatio
 			Rectangle {
 				color: "transparent"
 				opacity: 0.6

qt-mobile/qmlprofile.cpp

@@ -40,21 +40,30 @@ void QMLProfile::setDiveId(const QString &diveId)
 	static bool firstRun = true;
 	static QTransform profileTransform;
 	m_diveId = diveId;
-	double marginFactor = 0.013;  // margin as proportion of profile display width
 	struct dive *d = get_dive_by_uniq_id(m_diveId.toInt());
 	if (m_diveId.toInt() < 1)
 		return;
 	if (!d)
 		return;
-
+	//qDebug() << "setDiveId called with pos/size" << x() << y() << width() << height();
-	qDebug() << "setDiveId called with pos/size" << x() << y() << width() << height();
 	// set the profile widget's geometry and scale the viewport so
 	// the scene fills it, then plot the dive on that widget
+	// the profile widget doesn't handle subsequent geometry changes well,
+	// so only do it once, then scale the image to the item's dimension.
 	if (firstRun) {
 		firstRun = false;
 		m_profileWidget->setGeometry(QRect(x(), y(), width(), height()));
-		profileTransform.scale(width() / 100, height() / 100);
 	}
+	// scale the profile widget's image to devicePixelRatio and a magic number
+	qreal dpr = (80 * (m_devicePixelRatio > 2 ? m_devicePixelRatio : 1.0));
+	qreal sx = width() / dpr;
+	qreal sy = height() / dpr;
+	// don't forget to reset, otherwise we're
+	// scaling scaled items, growing it bigger and bigger with every pass
+	profileTransform.reset();
+	profileTransform.scale(sx, sy);
+	//qDebug() << "scale:" << sx << sy;
+
 	m_profileWidget->setTransform(profileTransform);
 	qDebug() << "effective transformation:" <<
 		    m_profileWidget->transform().m11() <<
@@ -66,10 +75,18 @@ void QMLProfile::setDiveId(const QString &diveId)
 		    m_profileWidget->transform().m31() <<
 		    m_profileWidget->transform().m32() <<
 		    m_profileWidget->transform().m33();
-
 	m_profileWidget->plotDive(d);
-	// scale the profile to create a margin
+}
-	// the profile height is ~2/3 the width, so to create an even margin,
+
-	// the scale reduction for height should be 3/2 the reduction for width
+qreal QMLProfile::devicePixelRatio() const
-	m_profileWidget->scale(1 - 2 * marginFactor, 1 - 3 * marginFactor);
+{
+	return m_devicePixelRatio;
+}
+
+void QMLProfile::setDevicePixelRatio(qreal dpr)
+{
+	if (dpr != m_devicePixelRatio) {
+		m_devicePixelRatio = dpr;
+		emit devicePixelRatioChanged();
+	}
 }

qt-mobile/qmlprofile.h

@@ -9,6 +9,8 @@ class QMLProfile : public QQuickPaintedItem
 {
 	Q_OBJECT
 	Q_PROPERTY(QString diveId READ diveId WRITE setDiveId NOTIFY diveIdChanged)
+	Q_PROPERTY(qreal devicePixelRatio READ devicePixelRatio WRITE setDevicePixelRatio NOTIFY devicePixelRatioChanged)
+
 public:
 	explicit QMLProfile(QQuickItem *parent = 0);
 	virtual ~QMLProfile();
@@ -17,15 +19,20 @@ public:
 
 	QString diveId() const;
 	void setDiveId(const QString &diveId);
+	qreal devicePixelRatio() const;
+	void setDevicePixelRatio(qreal dpr);
+
 public slots:
 	void setMargin(int margin);
 private:
 	QString m_diveId;
+	qreal m_devicePixelRatio;
 	int m_margin;
 	ProfileWidget2 *m_profileWidget;
 signals:
 	void rightAlignedChanged();
 	void diveIdChanged();
+	void devicePixelRatioChanged();
 };
 
 #endif // QMLPROFILE_H