[Qt-interest] cannot grab gesture with qgraphicsobject

[Wathek LOUED]

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
>>>
>>
>>
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>>
>
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