KDE Core/Platform 11/Eliminating Duplication With Qt: Difference between revisions

Revision as of 19:34, 4 June 2011

Team Members

Olivier, Volker,John, Helios, Ishmail.

Post-it Notes

Merge, Augment, Kill
Small changes in Qt to improve KDE contributions
How can we get mindset change in KDE towards Qt
Bigger things like Printing, QDateTime, maintainerships
Fixing QUrl so that KUrl is not necessary
Replacing QSettings with KConfig DConf? Kiosk?
KAction - Add default shortcut to QAction, global shortcuts
KLocale - Move to Qt
tr / i18n - gettext, script, KLocalizedString - move to Qt

Notes

Kconfig / QSettings / DConf - No-one felt qualified to discuss this, needs a separate break-out group

A Good Thing (TM), let's do it
Freeze kdelibs4, but not too hard may need changes or can backport some KDE5 stuff
Must start now to get what we need into Qt5 or will miss the chance
Not everything needs to be in Qt 5.0, but do need to be structured so we can cleanly add new features in 5.1, 5.2
Much depends on success of OpenGov
All contributions from KDE must be seen as for better of Qt not just KDE, we need to be pragmatic
If get in early with quality contributions can establish position of trust and authority
Start small with some test cases to prove process, gain trust:
- KUrl/QUrl - Very simple case with minimal change required
- KLineEdit/QLineEdit(?) - More involved case
- QDateTime - Test for working with Qt Brisbane to develop common requirements
- Printing - Big test case for major changes + maintainership
Review progress at Desktop Summit, if good progress then commit to full process
Need class-by-class review:
- Work with dependencies team, need common notes somewhere
- Will need expert advice on each class, we can't know every reason for duplication
- Find if a Qt equivalent (not always obvious!)
- Determine why KDE version exists
- Determine if Qt version is already good enough (may have improved since K class created)
- Determine if we really still need any extra features
- Need to consider features, quality, performance
- Reach a conclusion:
  - Keep K class entirely
  - Keep K class but move some features to Qt
  - Remove K class, use Q class completely
  - Remove K class, use Q class with new K helper class
Licence:
- Need review by eV lawyers to reassure contributors they don't lose rights, are fully informed of consequences, start asap as may take time
- Create list of known contributors who have/will agree to Qt license so we can reuse their code if appropriate (will still need explicit agreement per contribution?)
- Need to be very careful don't copy code of those who oppose code donations
Automated tools for convert?

Specific classes/modules

Some obvious stuff from off top of our collective head:

QtLocation: Move QGeoCoordinate and poss QGeoAddress from QtLocation to QtCore as fundamental data type
KUrl / QUrl
KIcon / QIcon
KDateTime / QDateTime
KLocale / QLocale
KAction / QAction
KSSL*
KCodec
KlineEdit / QlineEdit
KComboBox / QComboBox
KCompleter
...

Some random other notes:

QDate/QTime don't have a qHash?

GeoLocation

Qt5 Proposal: Move QGeoCoordinate and maybe QGeoAddress from QtLocation to QtCore as fundamental data types.

Discussed with Torstan / Marble guys and they are in favour. Torstan may be at QCS so can add input there.

Move QGeoCoordinates from QtLocation to QtCore:

Basic structure is fine
Extra to/from string methods would be very good to add, probably acceptable to Qt
Marble stores matrix/quaternion for performance, not sure how acceptable to Qt

QGeoAddress not match in Marble, may be useful, is a clean stand-alone implementation.

Marble API (simplified):

class GEODATA_EXPORT GeoDataCoordinates {

public:
   enum Unit{
       Radian,
       Degree
   };

   enum Notation{
       Decimal,
       DMS
   };

   // Type definitions
   typedef QVector<GeoDataCoordinates> Vector;
   typedef QVector<GeoDataCoordinates*> PtrVector;

   GeoDataCoordinates( const GeoDataCoordinates& other );
   GeoDataCoordinates();

   GeoDataCoordinates( qreal lon, qreal lat, qreal alt = 0,
                       GeoDataCoordinates::Unit unit = GeoDataCoordinates::Radian,
                       int detail = 0 );

   virtual ~GeoDataCoordinates();

   void set( qreal lon, qreal lat, qreal alt = 0,
             GeoDataCoordinates::Unit unit = GeoDataCoordinates::Radian );
   void geoCoordinates( qreal& lon, qreal& lat,
                        GeoDataCoordinates::Unit unit = GeoDataCoordinates::Radian ) const;

   void setLongitude( qreal lon,
             GeoDataCoordinates::Unit unit = GeoDataCoordinates::Radian );
   qreal longitude( GeoDataCoordinates::Unit unit = GeoDataCoordinates::Radian )
                                                               const;

   void setLatitude( qreal lat,
             GeoDataCoordinates::Unit unit = GeoDataCoordinates::Radian );
   qreal latitude( GeoDataCoordinates::Unit unit = GeoDataCoordinates::Radian ) const;

   void setAltitude( const qreal altitude );
   qreal altitude() const;

   void setDetail( const int det );
   int detail() const;

   const Quaternion &quaternion() const;

   bool isPole( Pole = AnyPole ) const;

   static void setDefaultNotation( GeoDataCoordinates::Notation notation );
   static GeoDataCoordinates::Notation defaultNotation();

   static qreal normalizeLon( qreal lon,
                              GeoDataCoordinates::Unit = GeoDataCoordinates::Radian );
   static qreal normalizeLat( qreal lat,
                              GeoDataCoordinates::Unit = GeoDataCoordinates::Radian );
   static void normalizeLonLat( qreal &lon, qreal &lat,
                                GeoDataCoordinates::Unit = GeoDataCoordinates::Radian );

   static GeoDataCoordinates fromString( const QString &string, bool& successful );

   QString toString() const;
   QString toString( GeoDataCoordinates::Notation notation, int precision = -1 ) const;
   static QString lonToString( qreal lon, GeoDataCoordinates::Notation notation,
                                          GeoDataCoordinates::Unit unit = Radian,
                                          int precision = -1,
                                          char format = 'f' );
   QString lonToString() const;
   static QString latToString( qreal lat, GeoDataCoordinates::Notation notation,
                                          GeoDataCoordinates::Unit unit = Radian,
                                          int precision = -1,
   QString latToString() const;

   bool operator==( const GeoDataCoordinates& ) const;
   GeoDataCoordinates& operator=( const GeoDataCoordinates &other );

   virtual void pack( QDataStream& stream ) const;
   virtual void unpack( QDataStream& stream );

   virtual void detach();

};

Qt 5 Code (simplified):

class Q_LOCATION_EXPORT QGeoCoordinate { public:

   enum CoordinateType {
       InvalidCoordinate,
       Coordinate2D,
       Coordinate3D
   };

   enum CoordinateFormat {
       Degrees,
       DegreesWithHemisphere,
       DegreesMinutes,
       DegreesMinutesWithHemisphere,
       DegreesMinutesSeconds,
       DegreesMinutesSecondsWithHemisphere
   };

   QGeoCoordinate();
   QGeoCoordinate(double latitude, double longitude);
   QGeoCoordinate(double latitude, double longitude, double altitude);
   QGeoCoordinate(const QGeoCoordinate &other);
   ~QGeoCoordinate();

   QGeoCoordinate &operator=(const QGeoCoordinate &other);

   bool operator==(const QGeoCoordinate &other) const;
   inline bool operator!=(const QGeoCoordinate &other) const {
       return !operator==(other);
   }

   bool isValid() const;
   CoordinateType type() const;

   void setLatitude(double latitude);
   double latitude() const;

   void setLongitude(double longitude);
   double longitude() const;

   void setAltitude(double altitude);
   double altitude() const;

   qreal distanceTo(const QGeoCoordinate &other) const;
   qreal azimuthTo(const QGeoCoordinate &other) const;

   QGeoCoordinate atDistanceAndAzimuth(qreal distance, qreal azimuth, qreal distanceUp = 0.0) const;

   QString toString(CoordinateFormat format = DegreesMinutesSecondsWithHemisphere) const;

private:

   QGeoCoordinatePrivate *d;

   friend class QGeoCoordinatePrivate;

};

Locale

What's wrong with KLocale:

Gtk/Qt apps running under kde-workspace don't use KDE locale
KDE apps running under other platforms/workspaces do not use host locale
Class merges settings, formatters, parsers and translations in one giant blob
Unnecessary dependency for Qt-Addon libraries

What's great about KLocale:

Users can change settings
Apps can change settings
Superior settings, date/time, etc support

What's wrong with QLocale:

Not all settings are supported
Apps and users unable to change settings

What's good with QLocale:

Uses host settings on all platforms
Low-level common class so good for Qt Addons

Date/Time

http://community.kde.org/KDE_Core/QtMerge/QDateTime