Android: fix camera viewfinder orientation.

The camera sensor on Android devices might be in a different orientation
than the device natural orientation. There is no API in Qt to know about
the camera orientation, so correcting the viewfinder orientation is not
possible without making guesses. This patch makes sure the viewfinder
orientation always matches the device natural orientation. For example,
if the camera is mounted in landscape, and the device natural
orientation is portrait, the viewfinder will automatically be rotated 90
degrees counter-clockwise.

Task-number: QTBUG-35086
Change-Id: Ia890872971d72657debe709f61edba27d09dec65
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

1 files changed, 32 insertions, 5 deletions

diff --git a/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp b/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
index 3a50139c3..5ff19d1c1 100644
--- a/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
+++ b/src/plugins/android/src/mediacapture/qandroidcamerasession.cpp
@@ -92,6 +92,7 @@ QAndroidCameraSession::QAndroidCameraSession(QObject *parent)
     , m_selectedCamera(0)
     , m_camera(0)
     , m_nativeOrientation(0)
+    , m_previewOrientation(0)
     , m_videoOutput(0)
     , m_captureMode(QCamera::CaptureViewfinder)
     , m_state(QCamera::UnloadedState)
@@ -183,10 +184,20 @@ bool QAndroidCameraSession::open()
         connect(m_camera, SIGNAL(pictureExposed()), this, SLOT(onCameraPictureExposed()));
         connect(m_camera, SIGNAL(pictureCaptured(QByteArray)), this, SLOT(onCameraPictureCaptured(QByteArray)));
         connect(m_camera, SIGNAL(previewFrameAvailable(QByteArray)), this, SLOT(onCameraPreviewFrameAvailable(QByteArray)));
+
         m_nativeOrientation = m_camera->getNativeOrientation();
+
+        // Preview orientation will always match the device natural orientation
+        if (m_camera->getFacing() == JCamera::CameraFacingFront)
+            m_previewOrientation = 360 - m_nativeOrientation;
+        else
+            m_previewOrientation = m_nativeOrientation;
+
         m_status = QCamera::LoadedStatus;
+
         if (m_camera->getPreviewFormat() != JCamera::NV21)
             m_camera->setPreviewFormat(JCamera::NV21);
+
         emit opened();
     } else {
         m_status = QCamera::UnavailableStatus;
@@ -257,8 +268,16 @@ void QAndroidCameraSession::adjustViewfinderSize(const QSize &captureSize, bool
     }
 
     if (m_camera->previewSize() != viewfinderResolution) {
-        if (m_videoOutput)
-            m_videoOutput->setVideoSize(viewfinderResolution);
+        if (m_videoOutput) {
+            QSize size = viewfinderResolution;
+
+            // If the preview orientation is not the defaut one (0 or 180 degrees),
+            // we have to invert the output aspect ratio.
+            if (m_previewOrientation % 180)
+                size.transpose();
+
+            m_videoOutput->setVideoSize(size);
+        }
 
         // if preview is started, we have to stop it first before changing its size
         if (m_previewStarted && restartPreview)
@@ -282,6 +301,7 @@ void QAndroidCameraSession::startPreview()
 
     applyImageSettings();
     adjustViewfinderSize(m_imageSettings.resolution());
+    m_camera->setDisplayOrientation(m_previewOrientation);
 
     if (m_videoOutput && m_videoOutput->isReady())
         onVideoOutputReady(true);
@@ -558,10 +578,11 @@ void QAndroidCameraSession::onCameraPreviewFrameAvailable(const QByteArray &data
 
     QtConcurrent::run(this, &QAndroidCameraSession::processPreviewImage,
                       m_currentImageCaptureId,
-                      data);
+                      data,
+                      m_camera->getRotation());
 }
 
-void QAndroidCameraSession::processPreviewImage(int id, const QByteArray &data)
+void QAndroidCameraSession::processPreviewImage(int id, const QByteArray &data, int rotation)
 {
     QSize frameSize = m_camera->previewSize();
     QImage preview(frameSize, QImage::Format_ARGB32);
@@ -570,11 +591,17 @@ void QAndroidCameraSession::processPreviewImage(int id, const QByteArray &data)
                               frameSize.width(),
                               frameSize.height());
 
+    QTransform transform;
+
     // Preview display of front-facing cameras is flipped horizontally, but the frame data
     // we get here is not. Flip it ourselves if the camera is front-facing to match what the user
     // sees on the viewfinder.
     if (m_camera->getFacing() == JCamera::CameraFacingFront)
-        preview = preview.transformed(QTransform().scale(-1, 1));
+        transform.scale(-1, 1);
+
+    transform.rotate(rotation);
+
+    preview = preview.transformed(transform);
 
     emit imageCaptured(id, preview);
 }