Android: Fix camera preview orientation

Before API level 24 the display orientation (the preview) was always
set to 0. On newer versions of Android the clockwise rotation is set
to be either 0 or 180, depending on the hardware. Since we don't
want Android to apply transformation on our surface, we'll just
enforce that the display orientation is always set to 0.

Task-number: QTBUG-56536
Change-Id: Ie1aacda97540d5c97e6cbd8edb2afc53e7041e1e
Reviewed-by: Andy Shaw <andy.shaw@qt.io>

3 files changed, 19 insertions, 0 deletions

diff --git a/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp b/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
index 8663f8c5f..b0dd7d900 100644
--- a/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
+++ b/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
@@ -52,6 +52,7 @@
 #include <qvideoframe.h>
 #include <private/qmemoryvideobuffer_p.h>
 #include <private/qvideoframe_p.h>
+#include <QtCore/private/qjnihelpers_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -443,6 +444,11 @@ bool QAndroidCameraSession::startPreview()
 
     AndroidMultimediaUtils::enableOrientationListener(true);
 
+    // Before API level 24 the orientation was always 0, which is what we're expecting, so
+    // we'll enforce that here.
+    if (QtAndroidPrivate::androidSdkVersion() > 23)
+        m_camera->setDisplayOrientation(0);
+
     m_camera->startPreview();
     m_previewStarted = true;
 
diff --git a/src/plugins/android/src/wrappers/jni/androidcamera.cpp b/src/plugins/android/src/wrappers/jni/androidcamera.cpp
index 76d3ffb44..0f2a43531 100644
--- a/src/plugins/android/src/wrappers/jni/androidcamera.cpp
+++ b/src/plugins/android/src/wrappers/jni/androidcamera.cpp
@@ -196,6 +196,7 @@ public:
     Q_INVOKABLE void updatePreviewSize();
     Q_INVOKABLE bool setPreviewTexture(void *surfaceTexture);
     Q_INVOKABLE bool setPreviewDisplay(void *surfaceHolder);
+    Q_INVOKABLE void setDisplayOrientation(int degrees);
 
     Q_INVOKABLE bool isZoomSupported();
     Q_INVOKABLE int getMaxZoom();
@@ -481,6 +482,12 @@ bool AndroidCamera::setPreviewDisplay(AndroidSurfaceHolder *surfaceHolder)
     return ok;
 }
 
+void AndroidCamera::setDisplayOrientation(int degrees)
+{
+    Q_D(AndroidCamera);
+    QMetaObject::invokeMethod(d, "setDisplayOrientation", Qt::QueuedConnection, Q_ARG(int, degrees));
+}
+
 bool AndroidCamera::isZoomSupported()
 {
     Q_D(AndroidCamera);
@@ -1079,6 +1086,11 @@ bool AndroidCameraPrivate::setPreviewDisplay(void *surfaceHolder)
     return !exceptionCheckAndClear(env);
 }
 
+void AndroidCameraPrivate::setDisplayOrientation(int degrees)
+{
+    m_camera.callMethod<void>("setDisplayOrientation", "(I)V", degrees);
+}
+
 bool AndroidCameraPrivate::isZoomSupported()
 {
     QMutexLocker parametersLocker(&m_parametersMutex);
diff --git a/src/plugins/android/src/wrappers/jni/androidcamera.h b/src/plugins/android/src/wrappers/jni/androidcamera.h
index 1a59ff3c7..e58a81f8e 100644
--- a/src/plugins/android/src/wrappers/jni/androidcamera.h
+++ b/src/plugins/android/src/wrappers/jni/androidcamera.h
@@ -136,6 +136,7 @@ public:
     void setPreviewSize(const QSize &size);
     bool setPreviewTexture(AndroidSurfaceTexture *surfaceTexture);
     bool setPreviewDisplay(AndroidSurfaceHolder *surfaceHolder);
+    void setDisplayOrientation(int degrees);
 
     bool isZoomSupported();
     int getMaxZoom();