imageprovider.cpp Example File

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 #include <qqmlextensionplugin.h>

 #include <qqmlengine.h>
 #include <qquickimageprovider.h>
 #include <QImage>
 #include <QPainter>

 class ColorImageProvider : public QQuickImageProvider
 {
 public:
     ColorImageProvider()
         : QQuickImageProvider(QQuickImageProvider::Pixmap)
     {
     }

     QPixmap requestPixmap(const QString &id, QSize *size, const QSize &requestedSize) override
     {
         int width = 100;
         int height = 50;

         if (size)
             *size = QSize(width, height);
         QPixmap pixmap(requestedSize.width() > 0 ? requestedSize.width() : width,
                        requestedSize.height() > 0 ? requestedSize.height() : height);
         pixmap.fill(QColor(id).rgba());

         // write the color name
         QPainter painter(&pixmap);
         QFont f = painter.font();
         f.setPixelSize(20);
         painter.setFont(f);
         painter.setPen(Qt::black);
         if (requestedSize.isValid())
             painter.scale(requestedSize.width() / width, requestedSize.height() / height);
         painter.drawText(QRectF(0, 0, width, height), Qt::AlignCenter, id);

         return pixmap;
     }
 };

 class ImageProviderExtensionPlugin : public QQmlExtensionPlugin
 {
     Q_OBJECT
     Q_PLUGIN_METADATA(IID QQmlExtensionInterface_iid)
 public:
     void registerTypes(const char *uri) override
     {
         Q_UNUSED(uri);
     }

     void initializeEngine(QQmlEngine *engine, const char *uri) override
     {
         Q_UNUSED(uri);
         engine->addImageProvider("colors", new ColorImageProvider);
     }

 };

 #include "imageprovider.moc"