Add subtitle support to VideoOutput

Implement generic subtitle support for the QML VideoOuput element
by rendering subtitles through a QQuickTextNode.

Pick-to: 6.2
Change-Id: Ib6cd2763769891758fb1bb96964f30a38bdadefe
Reviewed-by: Samuel Mira <samuel.mira@qt.io>
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>

2 files changed, 5 insertions, 4 deletions

diff --git a/src/multimedia/video/qvideotexturehelper.cpp b/src/multimedia/video/qvideotexturehelper.cpp
index 27129c770..0f46c4805 100644
--- a/src/multimedia/video/qvideotexturehelper.cpp
+++ b/src/multimedia/video/qvideotexturehelper.cpp
@@ -505,12 +505,12 @@ int updateRhiTextures(QVideoFrame frame, QRhi *rhi, QRhiResourceUpdateBatch *res
     return description->nplanes;
 }
 
-void SubtitleLayout::updateFromVideoFrame(const QVideoFrame &frame)
+bool SubtitleLayout::updateFromVideoFrame(const QVideoFrame &frame)
 {
     auto text = frame.subtitleText();
     text.replace(QLatin1Char('\n'), QChar::LineSeparator);
     if (layout.text() == text && videoSize == frame.size())
-        return;
+        return false;
 
     videoSize = frame.size();
     QFont font;
@@ -521,7 +521,7 @@ void SubtitleLayout::updateFromVideoFrame(const QVideoFrame &frame)
     layout.setText(text);
     if (text.isEmpty()) {
         bounds = {};
-        return;
+        return true;
     }
     layout.setFont(font);
     QTextOption option;
@@ -557,6 +557,7 @@ void SubtitleLayout::updateFromVideoFrame(const QVideoFrame &frame)
     textWidth += fontSize/4.;
 
     bounds = QRectF((videoSize.width() - textWidth)/2., y, textWidth, height);
+    return true;
 }
 
 void SubtitleLayout::draw(QPainter *painter, const QRectF &videoRect) const
diff --git a/src/multimedia/video/qvideotexturehelper_p.h b/src/multimedia/video/qvideotexturehelper_p.h
index 261d55cf0..168ce8a86 100644
--- a/src/multimedia/video/qvideotexturehelper_p.h
+++ b/src/multimedia/video/qvideotexturehelper_p.h
@@ -107,7 +107,7 @@ struct Q_MULTIMEDIA_EXPORT SubtitleLayout
     QRectF bounds;
     QTextLayout layout;
 
-    void updateFromVideoFrame(const QVideoFrame &frame);
+    bool updateFromVideoFrame(const QVideoFrame &frame);
     void draw(QPainter *painter, const QRectF &videoRect) const;
     QImage toImage() const;
 };