Android: fixed image capture preview.

We used to generate the capture preview from the video output, grabbing
the pixels of the last frame (in a FBO). This is not possible anymore,
we instead query the camera for a preview frame, which is in the NV21
format and needs to be converted to RGB.

Change-Id: I1c728b3a708a6f052a83aebf9f15f511eab7a02f
Reviewed-by: Christian Stromme <christian.stromme@digia.com>

2 files changed, 53 insertions, 1 deletions

diff --git a/src/plugins/android/src/wrappers/jcamera.cpp b/src/plugins/android/src/wrappers/jcamera.cpp
index f53fa4936..f858f4702 100644
--- a/src/plugins/android/src/wrappers/jcamera.cpp
+++ b/src/plugins/android/src/wrappers/jcamera.cpp
@@ -102,6 +102,18 @@ static void notifyPictureCaptured(JNIEnv *env, jobject, int id, jbyteArray data)
     }
 }
 
+static void notifyPreviewFrame(JNIEnv *env, jobject, int id, jbyteArray data)
+{
+    JCamera *obj = g_objectMap.value(id, 0);
+    if (obj) {
+        QByteArray bytes;
+        int arrayLength = env->GetArrayLength(data);
+        bytes.resize(arrayLength);
+        env->GetByteArrayRegion(data, 0, arrayLength, (jbyte*)bytes.data());
+        Q_EMIT obj->previewFrameAvailable(bytes);
+    }
+}
+
 JCamera::JCamera(int cameraId, jobject cam)
     : QObject()
     , QJNIObjectPrivate(cam)
@@ -225,6 +237,23 @@ QList<QSize> JCamera::getSupportedPreviewSizes()
     return list;
 }
 
+JCamera::ImageFormat JCamera::getPreviewFormat()
+{
+    if (!m_parameters.isValid())
+        return Unknown;
+
+    return JCamera::ImageFormat(m_parameters.callMethod<jint>("getPreviewFormat"));
+}
+
+void JCamera::setPreviewFormat(ImageFormat fmt)
+{
+    if (!m_parameters.isValid())
+        return;
+
+    m_parameters.callMethod<void>("setPreviewFormat", "(I)V", jint(fmt));
+    applyParameters();
+}
+
 void JCamera::setPreviewSize(const QSize &size)
 {
     if (!m_parameters.isValid())
@@ -624,6 +653,11 @@ void JCamera::setJpegQuality(int quality)
     applyParameters();
 }
 
+void JCamera::requestPreviewFrame()
+{
+    callMethod<void>("requestPreviewFrame");
+}
+
 void JCamera::takePicture()
 {
     callMethod<void>("takePicture");
@@ -672,7 +706,8 @@ QStringList JCamera::callStringListMethod(const char *methodName)
 static JNINativeMethod methods[] = {
     {"notifyAutoFocusComplete", "(IZ)V", (void *)notifyAutoFocusComplete},
     {"notifyPictureExposed", "(I)V", (void *)notifyPictureExposed},
-    {"notifyPictureCaptured", "(I[B)V", (void *)notifyPictureCaptured}
+    {"notifyPictureCaptured", "(I[B)V", (void *)notifyPictureCaptured},
+    {"notifyPreviewFrame", "(I[B)V", (void *)notifyPreviewFrame}
 };
 
 bool JCamera::initJNI(JNIEnv *env)
diff --git a/src/plugins/android/src/wrappers/jcamera.h b/src/plugins/android/src/wrappers/jcamera.h
index 0aea81f38..464ca3cb2 100644
--- a/src/plugins/android/src/wrappers/jcamera.h
+++ b/src/plugins/android/src/wrappers/jcamera.h
@@ -58,6 +58,16 @@ public:
         CameraFacingFront = 1
     };
 
+    enum ImageFormat { // same values as in android.graphics.ImageFormat Java class
+        Unknown = 0,
+        RGB565 = 4,
+        NV16 = 16,
+        NV21 = 17,
+        YUY2 = 20,
+        JPEG = 256,
+        YV12 = 842094169
+    };
+
     ~JCamera();
 
     static JCamera *open(int cameraId);
@@ -75,6 +85,9 @@ public:
     QSize getPreferredPreviewSizeForVideo();
     QList<QSize> getSupportedPreviewSizes();
 
+    ImageFormat getPreviewFormat();
+    void setPreviewFormat(ImageFormat fmt);
+
     QSize previewSize() const { return m_previewSize; }
     void setPreviewSize(const QSize &size);
     void setPreviewTexture(jobject surfaceTexture);
@@ -131,6 +144,8 @@ public:
     void startPreview();
     void stopPreview();
 
+    void requestPreviewFrame();
+
     void takePicture();
 
     static bool initJNI(JNIEnv *env);
@@ -143,6 +158,8 @@ Q_SIGNALS:
 
     void whiteBalanceChanged();
 
+    void previewFrameAvailable(const QByteArray &data);
+
     void pictureExposed();
     void pictureCaptured(const QByteArray &data);