[Qt-interest] cannot grab gesture with qgraphicsobject

[Wathek LOUED]

Sean,

I'm sorry but your changes doesn't make any difference. But there's one
thing that I don't understand why do the QGesture::state() doesn't change ?
it's always the same equal to 0 which mean NoGesture.

On Thu, Mar 10, 2011 at 6:22 PM, Wathek LOUED <wathek at gmail.com> wrote:

> Hi Sean,
>
> Thank you for your reponse I'm trying that and I'll tell you if it's Ok.
>
> Thank you so much.
>
> Sincerely
> Wathek
>
>
> On Thu, Mar 10, 2011 at 5:17 PM, Sean Hayes <sean.t.hayes at vanderbilt.edu>wrote:
>
>> The problem is that in your TabGestureRecognizer you are setting the
>> result to canceled for gestures that have not been triggered (e.g.,
>> non-touch events). Note the changes I made to your recognize() function
>> below. Also, note that you do not need the mouse event code there.
>>
>> QGestureRecognizer::Result TapGestureRecognizer::recognize(QGesture
>> *state, QObject *, QEvent *event)
>> {
>>  TapGesture *q = static_cast<TapGesture *>(state);
>> const QTouchEvent *ev = static_cast<const QTouchEvent *>(event);
>>  QGestureRecognizer::Result result = *QGestureRecognizer::Ignore*;
>>
>> switch (event->type()) {
>>  case QEvent::TouchBegin: {
>> q->setPosition(ev->touchPoints().at(0).pos());
>>  q->setHotSpot(ev->touchPoints().at(0).screenPos());
>> q->start();
>>  result = QGestureRecognizer::MayBeGesture;
>> break;
>>  }
>> case QEvent::TouchUpdate:
>>  case QEvent::TouchEnd: {
>> if (ev->touchPoints().size() == 1) {
>>  QTouchEvent::TouchPoint p = ev->touchPoints().at(0);
>> QPoint delta = p.pos().toPoint() - p.startPos().toPoint();
>>  if (delta.manhattanLength() <= Delta && q->elapsed() <= TimerInterval &&
>> event->type() == QEvent::TouchEnd)
>>  result = QGestureRecognizer::TriggerGesture;
>> else* if(q->state() == Qt::GestureUpdated || q->state() ==
>> Qt::GestureStarted)*
>>  result = QGestureRecognizer::CancelGesture;
>> }
>>  break;
>> }
>>  }
>> return result;
>>  }
>>
>> On Wed, Mar 9, 2011 at 10:34 AM, Wathek LOUED <wathek at gmail.com> wrote:
>>
>>> Hi Till,
>>>
>>> Thank you for your response I've already seen your bug post but
>>> unfortunatly that doesn't help. Here are some part of my code :
>>>
>>> *gesturerecognizer class :*
>>> *
>>> *
>>> #ifndef GESTURERECOGNIZER_H
>>> #define GESTURERECOGNIZER_H
>>>
>>> #include "tapgesture.h"
>>> #include "tapandholdgesture.h"
>>>
>>> #include <QGestureRecognizer>
>>> #include <QGesture>
>>> #include <QEvent>
>>> #include <QObject>
>>> #include <QHash>
>>>
>>> class TapGestureRecognizer: public QGestureRecognizer
>>> {
>>> public:
>>> TapGestureRecognizer();
>>>  QGesture *create(QObject *target);
>>> QGestureRecognizer::Result recognize(QGesture *state, QObject *watched,
>>> QEvent *event);
>>>  void reset(QGesture *state);
>>> private:
>>> enum { TimerInterval = 400  };
>>> enum { Delta = 20 };
>>>  QHash<long, TapGesture *> touchPoints;
>>> };
>>> #endif
>>>
>>> #include "gesturerecognizer.h"
>>>
>>> #include <QWidget>
>>> #include <QTouchEvent>
>>> #include <QDebug>
>>> /*******************************************************
>>>  * TapGesture Recognizer
>>>  *******************************************************/
>>> TapGestureRecognizer::TapGestureRecognizer()
>>> {}
>>>
>>> QGesture *TapGestureRecognizer::create(QObject *target)
>>> {
>>> if (target && target->isWidgetType())
>>>  static_cast<QWidget *>(target)->setAttribute(Qt::WA_AcceptTouchEvents);
>>> return new TapGesture;
>>> }
>>>
>>> QGestureRecognizer::Result TapGestureRecognizer::recognize(QGesture
>>> *state, QObject *, QEvent *event)
>>> {
>>> TapGesture *q = static_cast<TapGesture *>(state);
>>>  const QTouchEvent *ev = static_cast<const QTouchEvent *>(event);
>>> QGestureRecognizer::Result result = QGestureRecognizer::CancelGesture;
>>>
>>> switch (event->type()) {
>>> case QEvent::TouchBegin: {
>>> q->setPosition(ev->touchPoints().at(0).pos());
>>>  q->setHotSpot(ev->touchPoints().at(0).screenPos());
>>> q->start();
>>> result = QGestureRecognizer::MayBeGesture;
>>>  break;
>>> }
>>> case QEvent::TouchUpdate:
>>> case QEvent::TouchEnd: {
>>>  if (ev->touchPoints().size() == 1) {
>>> QTouchEvent::TouchPoint p = ev->touchPoints().at(0);
>>> QPoint delta = p.pos().toPoint() - p.startPos().toPoint();
>>>  if (delta.manhattanLength() <= Delta && q->elapsed() <= TimerInterval
>>> && event->type() == QEvent::TouchEnd)
>>> result = QGestureRecognizer::TriggerGesture;
>>>  else
>>> result = QGestureRecognizer::CancelGesture;
>>> }
>>>  break;
>>> }
>>> case QEvent::MouseButtonPress:
>>> case QEvent::MouseMove:
>>>  case QEvent::MouseButtonRelease: {
>>> result = QGestureRecognizer::Ignore;
>>> break;
>>>  }
>>> default: {
>>> result = QGestureRecognizer::Ignore;
>>>  break;
>>> }
>>> }
>>>
>>> return result;
>>> }
>>>
>>> void TapGestureRecognizer::reset(QGesture *state)
>>> {
>>> TapGesture *q = static_cast<TapGesture *>(state);
>>> q->setPosition(QPointF());
>>>  QGestureRecognizer::reset(state);
>>> }
>>>
>>>
>>> *My QGraphicsView class :*
>>> *
>>> *
>>> #ifndef FRMACCUEIL_H
>>> #define FRMACCUEIL_H
>>>
>>> #include "gesture/gesturerecognizer.h"
>>>
>>> #include <QGraphicsView>
>>> #include <QGraphicsScene>
>>> #include <QGestureEvent>
>>> #include <QEvent>
>>> #include <QTouchEvent>
>>> #include <QHash>
>>>
>>> class FrmAccueil: public QGraphicsView
>>> {
>>> Q_OBJECT
>>> public:
>>> FrmAccueil(QGraphicsScene *scene=0, QWidget *parent=0);
>>> bool viewportEvent(QEvent *event);
>>>
>>> private:
>>> void gestureEvent(QGestureEvent *event);
>>> Qt::GestureType tapGesture;
>>>  TapGestureRecognizer *tapGestureRecognizer;
>>> };
>>>
>>> #endif
>>>
>>> #include "frmaccueil.h"
>>>
>>> #include <QDebug>
>>> #include <QGestureRecognizer>
>>>
>>> FrmAccueil::FrmAccueil(QGraphicsScene *scene, QWidget *parent)
>>>    :QGraphicsView(scene, parent)
>>>  {
>>> tapGestureRecognizer = new TapGestureRecognizer();
>>>
>>> tapGesture =
>>> QGestureRecognizer::registerRecognizer(tapGestureRecognizer);
>>>
>>>         viewport()->setAttribute(Qt::WA_AcceptTouchEvents);
>>> viewport()->grabGesture(tapGesture);
>>> }
>>>
>>>  bool FrmAccueil::viewportEvent(QEvent *event)
>>> {
>>> if (event->type() == QEvent::Gesture)
>>> gestureEvent(static_cast<QGestureEvent*>(event));
>>>
>>> return QGraphicsView::viewportEvent(event);
>>> }
>>>
>>> void FrmAccueil::gestureEvent(QGestureEvent *event)
>>> {
>>>  if (event->gesture(tapGesture))
>>> qDebug("TAP GESTURE");
>>> }
>>>
>>> *My QGraphicsScene class:*
>>>
>>> #ifndef PUSHBUTTONITEM_H
>>> #define PUSHBUTTONITEM_H
>>>
>>> #include "gesture/gesturerecognizer.h"
>>>
>>> #include <QGraphicsObject>
>>> #include <QEvent>
>>> #include <QGestureEvent>
>>> #include <QPixmap>
>>> #include <QPainter>
>>>
>>> class PushButtonItem:public QGraphicsObject
>>> {
>>> Q_OBJECT
>>> public:
>>> enum ShapeMode {
>>> MaskShape,
>>> BoundingRectShape,
>>>  HeuristicMaskShape
>>> };
>>>
>>> PushButtonItem(QGraphicsItem *parent=0);
>>>  QPainterPath shape() const;
>>>
>>> /* QGraphicsPixmapItem */
>>> QPixmap pixmap() const;
>>>  void setPixmap(const QPixmap &pixmap);
>>>
>>> Qt::TransformationMode transformationMode() const;
>>>  void setTransformationMode(Qt::TransformationMode transformation);
>>>
>>> QRectF boundingRect() const;
>>>  void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
>>> QWidget *widget=0);
>>>
>>> protected:
>>> bool sceneEvent(QEvent *event);
>>>
>>> private:
>>> void gestureEvent(QGestureEvent *event);
>>>
>>> ButtonType type;
>>>
>>> QList<GraphicsLineItem *> edgeList;
>>>  TapGestureRecognizer *tapGestureRecognizer;
>>> Qt::GestureType tapGesture;
>>>
>>> // QGraphicsPixmapItem
>>> QPixmap pix;
>>> bool hasShape;
>>>  Qt::TransformationMode transfMode;
>>> };
>>>
>>> #endif
>>>
>>> #include "pushbuttonitem.h"
>>>
>>> #include <QPixmap>
>>>
>>> #include <QDebug>
>>> #include <QTouchEvent>
>>> #include <QGestureRecognizer>
>>>
>>> PushButtonItem::PushButtonItem(QGraphicsItem *parent)
>>>        :QGraphicsObject(parent)
>>> {
>>> setFlags(QGraphicsItem::ItemIsMovable |
>>> QGraphicsItem::ItemSendsGeometryChanges);
>>>
>>> setTransformationMode(Qt::SmoothTransformation);
>>>   setAcceptTouchEvents(true);
>>>
>>> tapGestureRecognizer = new TapGestureRecognizer();
>>>  tapGesture =
>>> QGestureRecognizer::registerRecognizer(tapGestureRecognizer);
>>>
>>> grabGesture(tapGesture);
>>> }
>>>
>>> QPainterPath PushButtonItem::shape() const
>>> { return QGraphicsItem::shape();     }
>>>
>>> bool PushButtonItem::sceneEvent(QEvent *event)
>>> {
>>> qDebug("Event received");
>>> if (event->type() == QEvent::Gesture)
>>>  gestureEvent(static_cast<QGestureEvent *>(event));
>>> return true;
>>>
>>> }
>>>
>>> void PushButtonItem::gestureEvent(QGestureEvent *event)
>>> {
>>> if (event->gesture(tapGesture))
>>> qDebug("button Tapped");
>>> }
>>>
>>> /***************************************************************
>>>  * QGraphicsPixmapItem Reimplementation
>>>  ***************************************************************/
>>>
>>>
>>> I cannot really see where's the problem the QGraphicsView receive the
>>> gestureEvent but not the QGraphicsObject.
>>>
>>>
>>> Thank you so much
>>>
>>> Sincerely
>>> W.L
>>>
>>> On Mon, Mar 7, 2011 at 11:02 PM, Till Oliver Knoll <
>>> till.oliver.knoll at gmail.com> wrote:
>>>
>>>> Am 07.03.11 19:31, schrieb Wathek LOUED:
>>>>  > Hi,
>>>>  >
>>>>  > I got a problem with QGraphicsObject, I cannot grab gesture and I'm
>>>>  > getting this message : QGestureManager::deliverEvent: could not find
>>>> the
>>>>  > target for gesture.
>>>>
>>>> My experience up to Qt 4.7.1 is that QGestures are not as "mature" as
>>>> one would wish, especially on Mac.
>>>>
>>>> I had a somewhat similar issue that Pan gesture would not get through to
>>>> QGraphicsObjects in a QGraphicsScene. It turned out that this is a
>>>> "design issue" (how Gestures are implemented respective how items in a
>>>> scene deal with events) and won't be fixed:
>>>>
>>>>   http://bugreports.qt.nokia.com/browse/QTBUG-16618
>>>>
>>>> There is an example attached which shows how gestures SHOULD work with
>>>> QGraphicsObjects. Note that up to Qt 4.6.x also the QGraphicsView (the
>>>> view widget thereof!) had to grab the same gestures as the item itself.
>>>> This should not be necessary anymore with Qt 4.7.x.
>>>>
>>>> So in my case the QGraphicsObject did not receive Pan gesture events
>>>> (only the "start" event, but never the "update" or "end" events). Never
>>>> tried "Tab" events, but I got "pinch" (zoom/rotate) to work.
>>>>
>>>> But just now I am investigating another issue: it seems that the value
>>>> of
>>>>
>>>>  http://doc.trolltech.com/4.7/qpinchgesture.html#scaleFactor-prop
>>>>
>>>> returns different signed values on Mac and Windows 7. I developped my
>>>> app on Mac and implemented my "zoom" in such a way that when moving the
>>>> fingers apart the object would get bigger.
>>>>
>>>> A quick test on some netbook and laptop running Windows 7 revealed that
>>>> the "zoom" would work the other way (the object was scaled down instead
>>>> of scaled up). So I assume it is the sign which is different on Mac and
>>>> Windows 7 (= bug). But again, I did not have the opportunity yet to
>>>> reproduce this behaviour with debugging possibilities.
>>>>
>>>>
>>>> Hope that gives you some pointers,
>>>>   Oliver
>>>> _______________________________________________
>>>> Qt-interest mailing list
>>>> Qt-interest at qt.nokia.com
>>>> http://lists.qt.nokia.com/mailman/listinfo/qt-interest
>>>>
>>>
>>>
>>> _______________________________________________
>>> Qt-interest mailing list
>>> Qt-interest at qt.nokia.com
>>> http://lists.qt.nokia.com/mailman/listinfo/qt-interest
>>>
>>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.qt-project.org/pipermail/qt-interest-old/attachments/20110311/99804336/attachment.html