[Qt-interest] cannot grab gesture with qgraphicsobject

[Wathek LOUED]

Sean,

Unfortunatly even using Qt 4.7.2 under GNU/Linux 64bits doesn't change
anything. I still cannot grab gesture in QGraphicsObject.

Using the example you sent to me I still getting the message
QGestureManager::deliverEvent: could not find the target for gesture.

Sincerely
W.L

On Fri, Mar 11, 2011 at 4:17 PM, Wathek LOUED <wathek at gmail.com> wrote:

> Sean,
>
> I just tried your code and with Qt 4.6.3 and Debian 6.0 I'm
> getting QGestureManager::deliverEvent: could not find the target for gesture
> when I tap on the button but outside the button (on QGraphicsView) it works.
> But not with the QGraphicsObject.
>
> I'm downloading the sources of Qt 4.7.2 I'd like to try with that.
>
> Thank you
>
> On Fri, Mar 11, 2011 at 4:06 PM, Wathek LOUED <wathek at gmail.com> wrote:
>
>> Sean,
>>
>> I'm giving your code a try. I'm using Debian Squeeze with Qt 4.6.3.
>>
>>
>> On Fri, Mar 11, 2011 at 3:50 PM, Sean Hayes <sean.t.hayes at vanderbilt.edu>wrote:
>>
>>> Wathek,
>>>
>>> When I try the code I am getting gesture events in the
>>> QGraphicsObject/PushButtonItem. The state of these gesture events are
>>> Qt::GestureStarted. Also, I am no longer getting the "QGestureManager::deliverEvent:
>>> could not find the target for gesture" error.
>>>
>>> I am using Windows 7 and Qt 4.7.2. What is your setup? Attached is my
>>> example program based on your code. Let me know if that example works on
>>> your system.
>>>
>>> Sean
>>>
>>>
>>> On Fri, Mar 11, 2011 at 5:11 AM, Wathek LOUED <wathek at gmail.com> wrote:
>>>
>>>> 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
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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