Camera: Add bandaid for preview orientation on reverse-landscape cameras

Camera sensors on Android may be either landscape or reverse-landscape
oriented, but the vast majority of shipping devices only use landscape.

This means that many camera-using apps (which are generally forcing
themselves to landscape orientation) never call setDisplayOrientation,
since its default value of 0 is correct for the majority of devices.

However, there are some reverse-landscape devices, and for those, such
apps get upside-down preview.

This bandaid changes the default value of displayOrientation to be 180
on such devices, so that apps that never call setDisplayOrientation get
correct preview.  This bandaid has no effect on apps that do call
setDisplayOrientation, so hopefully such apps are doing the math
correctly.

Also update documentation to indicate that setDisplayOrientation should
be called, and to note the change in default orientation behavior in
Android N.

Change-Id: I1b2c957642fda8edead61bd07eda9d18c38d1fe6
Fixes: 27840948

2 files changed, 48 insertions, 3 deletions

diff --git a/core/java/android/hardware/Camera.java b/core/java/android/hardware/Camera.java
index 3dbe437a6c43..acf0677559fd 100644
--- a/core/java/android/hardware/Camera.java
+++ b/core/java/android/hardware/Camera.java
@@ -76,7 +76,7 @@ import static android.system.OsConstants.*;
  * <li>If necessary, modify the returned {@link Camera.Parameters} object and call
  * {@link #setParameters(Camera.Parameters)}.
  *
- * <li>If desired, call {@link #setDisplayOrientation(int)}.
+ * <li>Call {@link #setDisplayOrientation(int)} to ensure correct orientation of preview.
  *
  * <li><b>Important</b>: Pass a fully initialized {@link SurfaceHolder} to
  * {@link #setPreviewDisplay(SurfaceHolder)}.  Without a surface, the camera
@@ -1511,9 +1511,15 @@ public class Camera {
      * <p>Starting from API level 14, this method can be called when preview is
      * active.
      *
+     * <p><b>Note: </b>Before API level 24, the default value for orientation is 0. Starting in
+     * API level 24, the default orientation will be such that applications in forced-landscape mode
+     * will have correct preview orientation, which may be either a default of 0 or
+     * 180. Applications that operate in portrait mode or allow for changing orientation must still
+     * call this method after each orientation change to ensure correct preview display in all
+     * cases.</p>
+     *
      * @param degrees the angle that the picture will be rotated clockwise.
-     *                Valid values are 0, 90, 180, and 270. The starting
-     *                position is 0 (landscape).
+     *                Valid values are 0, 90, 180, and 270.
      * @see #setPreviewDisplay(SurfaceHolder)
      */
     public native final void setDisplayOrientation(int degrees);
diff --git a/core/jni/android_hardware_Camera.cpp b/core/jni/android_hardware_Camera.cpp
index 806fcc3619a1..91f003d59c46 100644
--- a/core/jni/android_hardware_Camera.cpp
+++ b/core/jni/android_hardware_Camera.cpp
@@ -567,6 +567,45 @@ static jint android_hardware_Camera_native_setup(JNIEnv *env, jobject thiz,
 
     // save context in opaque field
     env->SetLongField(thiz, fields.context, (jlong)context.get());
+
+    // Update default display orientation in case the sensor is reverse-landscape
+    CameraInfo cameraInfo;
+    status_t rc = Camera::getCameraInfo(cameraId, &cameraInfo);
+    if (rc != NO_ERROR) {
+        return rc;
+    }
+    int defaultOrientation = 0;
+    switch (cameraInfo.orientation) {
+        case 0:
+            break;
+        case 90:
+            if (cameraInfo.facing == CAMERA_FACING_FRONT) {
+                defaultOrientation = 180;
+            }
+            break;
+        case 180:
+            defaultOrientation = 180;
+            break;
+        case 270:
+            if (cameraInfo.facing != CAMERA_FACING_FRONT) {
+                defaultOrientation = 180;
+            }
+            break;
+        default:
+            ALOGE("Unexpected camera orientation %d!", cameraInfo.orientation);
+            break;
+    }
+    if (defaultOrientation != 0) {
+        ALOGV("Setting default display orientation to %d", defaultOrientation);
+        rc = camera->sendCommand(CAMERA_CMD_SET_DISPLAY_ORIENTATION,
+                defaultOrientation, 0);
+        if (rc != NO_ERROR) {
+            ALOGE("Unable to update default orientation: %s (%d)",
+                    strerror(-rc), rc);
+            return rc;
+        }
+    }
+
     return NO_ERROR;
 }