That's actually a good idea --- my model's pretty complex, so I wanted to keep
the provider separate so I could re-use it.
I like the idea of composing the two in the general case --- thanks!
R.
On Nov 19, 2010, at 9:41 AM, ext Jerzy Chalupski wrote:
> QDeclarativeImageProvider is not an QObject, so the model and image
> provider might be implemented in the same class:
>
> class MyAwesomeModel: public QAbstractItemModel, public
> QDeclarativeImageProvider
> {
> //...
> };
>
> The upside of this solution is that you can have a single data
> structure, so you don't have to implement data synchronization between
> model and image provider.
>
> 2010/11/19 <ray.rischpa...@nokia.com>:
>> Actually, you can return different images using the
>> QDeclarativeImageProvider and a C++ model --- simply have a role in the
>> model return a different string resource name for each model item (e.g.,
>> "image://model/1.png", "image://model/2.png", and so forth), and then have
>> the image provider return the appropriate image from the model. If you want
>> to be a bit faster, you can even have your image provider use a
>> QMap<QString, QModelIndex> to map from the image's name in the model to the
>> image. Based on Juha's feedback, I've got code running now I'm planning on
>> cleaning up a bit and posting to my blog in the near future. The crux of the
>> code is the requestPixmap method, which looks like this:
>>
>> class QAbstractItemModel;
>>
>> class ModelIndexProvider : public QObject, public QDeclarativeImageProvider
>> {
>> Q_OBJECT
>> public:
>> ModelIndexProvider(QAbstractItemModel& model, int pathRole, int
>> pixmapRole, QObject* parent = 0);
>> ~ModelIndexProvider();
>> QPixmap requestPixmap(const QString& id, QSize* size, const QSize&
>> requestedSize);
>>
>> public slots:
>> void dataUpdated(const QModelIndex & topLeft, const QModelIndex &
>> bottomRight);
>> void dataDeleted(const QModelIndex & parent, int start, int end);
>> void dataReset();
>>
>> private:
>> QAbstractItemModel& mModel;
>> int mPathRole;
>> int mPixmapRole;
>> QMap<QString, QModelIndex> mPixmapIndex;
>> };
>>
>> QPixmap ModelIndexProvider::requestPixmap(const QString& id, QSize* size,
>> const QSize& requestedSize)
>> {
>> QString key = QString("image://model/%1").arg(id);
>> QModelIndex index = mPixmapIndex[key];
>> QPixmap image = mModel.data(index, mPixmapRole).value<QPixmap>();
>> QPixmap result;
>>
>> if (requestedSize.isValid()) {
>> result = image.scaled(requestedSize, Qt::KeepAspectRatio);
>> } else {
>> result = image;
>> }
>> *size = result.size();
>> return result;
>> }
>>
>> Of course, the provider should be a QObject and connect to the model so that
>> when the model changes the pixmap index gets updated and so forth, but
>> that's pretty easy.
>>
>> Thanks again to Juha for the suggestion!
>>
>> On Nov 18, 2010, at 10:56 PM, ext Tuomas Niinistö wrote:
>>
>>> Juha Turunen <turu...@...> writes:
>>>
>>>>
>>>> Hi Ray,
>>>>
>>>> [ Use QDeclarativeImageProvider ]
>>>>
>>>> On Fri, Nov 12, 2010 at 7:42 PM, <ray.rischpa...@...> wrote:
>>>>> [ Question about returning images from models ]
>>>>> Nokia Research Center Palo Alto
>>>
>>> Hi,
>>>
>>> I have faced the same problem as Ray. And think that the
>>> QDeclarativeImageProvider does not help here, at least not directly.
>>>
>>> When you have a list object existing in native C++ side and you wan't to
>>> populate the QML ListView with it. For "normal" data like integers and
>>> strings
>>> it works fine by using QDeclarativeListProperty.
>>>
>>> But the problem comes when you want to have an individual image for each
>>> list
>>> item. With QDeclarativeImageProvider you can populate the list items with
>>> the
>>> same image instance, but how to have an individual image for each item
>>> seems to
>>> be problematic.
>>>
>>> Br, Tuomas
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Qt-qml mailing list
>>> Qt-qml@trolltech.com
>>> http://lists.trolltech.com/mailman/listinfo/qt-qml
>>
>>
>> _______________________________________________
>> Qt-qml mailing list
>> Qt-qml@trolltech.com
>> http://lists.trolltech.com/mailman/listinfo/qt-qml
>>
_______________________________________________
Qt-qml mailing list
Qt-qml@trolltech.com
http://lists.trolltech.com/mailman/listinfo/qt-qml
