Qt 5.6 | Qt Quick | C++ Extensions: Image Provider Example | imageprovider.cpp Example File

Qt 5.6.3 Reference Documentation

# imageprovider.cpp Example File

imageprovider/imageprovider.cpp

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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)
          {
              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)
          {
              Q_UNUSED(uri);
          }

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

      };

      #include "imageprovider.moc"