Add encoding speed option

This adds --speed option in kdynamicwallpaperbuilder, 0 - slowest speed,
10 - fastest. The encoding speed can potentially affect resulting file
size or encoding quality.

Example usage:

    kdynamicwallpaperbuilder --output foo.avif --speed 6 manifest.json

src/lib/kdynamicwallpaperwriter.cpp

@@ -36,6 +36,7 @@ class KDynamicWallpaperWriterPrivate
  QString errorString;
  QList<KDynamicWallpaperWriter::ImageView> images;
  QList<KDynamicWallpaperMetaData> metaData;
+ std::optional<int> speed;
  std::optional<int> maxThreadCount;
 };
 
@@ -90,6 +91,7 @@ bool KDynamicWallpaperWriterPrivate::flush(QIODevice *device)
 
  const QByteArray xmp = serializeMetaData(metaData);
  avifEncoder *encoder = avifEncoderCreate();
+ encoder->speed = speed.value_or(AVIF_SPEED_DEFAULT);
  encoder->maxThreads = maxThreadCount.value_or(QThread::idealThreadCount());
  auto encoderCleanup = qScopeGuard([&encoder]() {
  avifEncoderDestroy(encoder);
@@ -165,6 +167,25 @@ KDynamicWallpaperWriter::~KDynamicWallpaperWriter()
 {
 }
 
+/*!
+ * Sets the encoding speed to \a speed. The speed value must be between 0 and 10, where
+ * 0 is the slowest speed, and 10 is the fastest speed. Encoding speed can affect encoding
+ * quality or file size.
+ */
+void KDynamicWallpaperWriter::setSpeed(int speed)
+{
+ d->speed = qBound(0, speed, 10);
+}
+
+/*!
+ * Returns the encoding speed, between 0-10. If the encoding speed is not set, the encoder
+ * will choose the most optimal encoding speed.
+ */
+std::optional<int> KDynamicWallpaperWriter::speed() const
+{
+ return d->speed;
+}
+
 void KDynamicWallpaperWriter::setMetaData(const QList<KDynamicWallpaperMetaData> &metaData)
 {
  d->metaData = metaData;

src/lib/kdynamicwallpaperwriter.h

@@ -51,6 +51,9 @@ class KDYNAMICWALLPAPER_EXPORT KDynamicWallpaperWriter
  KDynamicWallpaperWriter();
  ~KDynamicWallpaperWriter();
 
+ void setSpeed(int speed);
+ std::optional<int> speed() const;
+
  void setMetaData(const QList<KDynamicWallpaperMetaData> &metaData);
  QList<KDynamicWallpaperMetaData> metaData() const;
 

src/tools/builder/main.cpp

@@ -26,6 +26,10 @@ int main(int argc, char **argv)
  outputOption.setDescription(i18n("Write output to <file>"));
  outputOption.setValueName(QStringLiteral("file"));
 
+ QCommandLineOption speedOption(QStringLiteral("speed"));
+ speedOption.setDescription(i18n("Encoding speed, 0 - slowest, 10 - fastest"));
+ speedOption.setValueName(QStringLiteral("speed"));
+
  QCommandLineOption maxThreadsOption(QStringLiteral("max-threads"));
  maxThreadsOption.setDescription(i18n("Maximum number of threads that can be used when encoding a wallpaper"));
  maxThreadsOption.setValueName(QStringLiteral("max-threads"));
@@ -36,6 +40,7 @@ int main(int argc, char **argv)
  parser.addPositionalArgument("json", i18n("Manifest file to use"));
  parser.addOption(outputOption);
  parser.addOption(maxThreadsOption);
+ parser.addOption(speedOption);
  parser.process(app);
 
  if (parser.positionalArguments().count() != 1)
@@ -61,6 +66,15 @@ int main(int argc, char **argv)
  }
  }
 
+ if (parser.isSet(speedOption)) {
+ bool ok;
+ if (const int speed = parser.value(speedOption).toInt(&ok); ok) {
+ writer.setSpeed(speed);
+ } else {
+ parser.showHelp(-1);
+ }
+ }
+
  QString targetFileName = parser.value(outputOption);
  if (targetFileName.isEmpty())
  targetFileName = QStringLiteral("wallpaper.avif");