Add QQuickAsyncImageProvider

It allows for providers to implement threading on their side

Change-Id: I34042b213ce7697a3e39470387357d733e15723c
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

1 files changed, 123 insertions, 0 deletions

diff --git a/examples/quick/imageresponseprovider/imageresponseprovider.cpp b/examples/quick/imageresponseprovider/imageresponseprovider.cpp
new file mode 100644
index 0000000000..bdec29114b
--- /dev/null
+++ b/examples/quick/imageresponseprovider/imageresponseprovider.cpp
@@ -0,0 +1,123 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Canonical Limited and/or its subsidiary(-ies)
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the demonstration applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#include <qqmlextensionplugin.h>
+
+#include <qqmlengine.h>
+#include <qquickimageprovider.h>
+#include <QDebug>
+#include <QImage>
+#include <QThreadPool>
+
+class AsyncImageResponse : public QQuickImageResponse, public QRunnable
+{
+    public:
+        AsyncImageResponse(const QString &id, const QSize &requestedSize)
+         : m_id(id), m_requestedSize(requestedSize), m_texture(0)
+        {
+            setAutoDelete(false);
+        }
+
+        QQuickTextureFactory *textureFactory() const
+        {
+            return m_texture;
+        }
+
+        void run()
+        {
+            QImage image(50, 50, QImage::Format_RGB32);
+            if (m_id == "slow") {
+                qDebug() << "Slow, red, sleeping for 5 seconds";
+                QThread::sleep(5);
+                image.fill(Qt::red);
+            } else {
+                qDebug() << "Fast, blue, sleeping for 1 second";
+                QThread::sleep(1);
+                image.fill(Qt::blue);
+            }
+            if (m_requestedSize.isValid())
+                image = image.scaled(m_requestedSize);
+            m_texture = QQuickTextureFactory::textureFactoryForImage(image);
+            emit finished();
+        }
+
+        QString m_id;
+        QSize m_requestedSize;
+        QQuickTextureFactory *m_texture;
+};
+
+class AsyncImageProvider : public QQuickAsyncImageProvider
+{
+public:
+    QQuickImageResponse *requestImageResponse(const QString &id, const QSize &requestedSize)
+    {
+        AsyncImageResponse *response = new AsyncImageResponse(id, requestedSize);
+        pool.start(response);
+        return response;
+    }
+
+private:
+    QThreadPool pool;
+};
+
+
+class ImageProviderExtensionPlugin : public QQmlExtensionPlugin
+{
+    Q_OBJECT
+    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QQmlExtensionInterface")
+public:
+    void registerTypes(const char *uri)
+    {
+        Q_UNUSED(uri);
+    }
+
+    void initializeEngine(QQmlEngine *engine, const char *uri)
+    {
+        Q_UNUSED(uri);
+        engine->addImageProvider("async", new AsyncImageProvider);
+    }
+
+};
+
+
+#define QQmlExtensionInterface_iid "org.qt-project.Qt.QQmlExtensionInterface"
+
+#include "imageresponseprovider.moc"