Add camera metering mode API.

bug:2737111
Change-Id: Ie986fee56ebeaaed2d2efb757701dfe3ffdec8d8

3 files changed, 79 insertions, 0 deletions

diff --git a/core/java/android/hardware/Camera.java b/core/java/android/hardware/Camera.java
index 54aa363..025db4a 100644
--- a/core/java/android/hardware/Camera.java
+++ b/core/java/android/hardware/Camera.java
@@ -763,6 +763,7 @@ public class Camera {
         private static final String KEY_ZOOM_SUPPORTED = "zoom-supported";
         private static final String KEY_SMOOTH_ZOOM_SUPPORTED = "smooth-zoom-supported";
         private static final String KEY_FOCUS_DISTANCES = "focus-distances";
+        private static final String KEY_METERING_MODE = "metering-mode";
 
         // Parameter key suffix for supported values.
         private static final String SUPPORTED_VALUES_SUFFIX = "-values";
@@ -965,6 +966,26 @@ public class Camera {
          */
         public static final String FOCUS_MODE_CONTINUOUS = "continuous";
 
+        /**
+         * The camera determines the exposure by giving more weight to the
+         * central part of the scene.
+         * @hide
+         */
+        public static final String METERING_MODE_CENTER_WEIGHTED = "center-weighted";
+
+        /**
+         * The camera determines the exposure by averaging the entire scene,
+         * giving no weighting to any particular area.
+         * @hide
+         */
+        public static final String METERING_MODE_FRAME_AVERAGE = "frame-average";
+
+        /**
+         * The camera determines the exposure by a very small area of the scene,
+         * typically the center.
+         * @hide
+         */
+        public static final String METERING_MODE_SPOT = "spot";
 
         // Formats for setPreviewFormat and setPictureFormat.
         private static final String PIXEL_FORMAT_YUV422SP = "yuv422sp";
@@ -1930,6 +1951,45 @@ public class Camera {
             output[2] = distances.get(2);
         }
 
+        /**
+         * Gets the supported metering modes.
+         *
+         * @return a list of supported metering modes. null if metering mode
+         *         setting is not supported.
+         * @see #getMeteringMode()
+         * @hide
+         */
+        public List<String> getSupportedMeteringModes() {
+            String str = get(KEY_METERING_MODE + SUPPORTED_VALUES_SUFFIX);
+            return split(str);
+        }
+
+        /**
+         * Gets the current metering mode, which affects how camera determines
+         * exposure.
+         *
+         * @return current metering mode. If the camera does not support
+         *         metering setting, this should return null.
+         * @see #METERING_MODE_CENTER_WEIGHTED
+         * @see #METERING_MODE_FRAME_AVERAGE
+         * @see #METERING_MODE_SPOT
+         * @hide
+         */
+        public String getMeteringMode() {
+            return get(KEY_METERING_MODE);
+        }
+
+        /**
+         * Sets the metering mode.
+         *
+         * @param value metering mode.
+         * @see #getMeteringMode()
+         * @hide
+         */
+        public void setMeteringMode(String value) {
+            set(KEY_METERING_MODE, value);
+        }
+
         // Splits a comma delimited string to an ArrayList of String.
         // Return null if the passing string is null or the size is 0.
         private ArrayList<String> split(String str) {
diff --git a/include/camera/CameraParameters.h b/include/camera/CameraParameters.h
index 2b7a86eb..4840b40 100644
--- a/include/camera/CameraParameters.h
+++ b/include/camera/CameraParameters.h
@@ -250,6 +250,10 @@ public:
     // Example value: "yuv420sp" or PIXEL_FORMAT_XXX constants. Read only.
     static const char KEY_VIDEO_FRAME_FORMAT[];
 
+    // Metering mode. This affects how camera determines exposure.
+    // Example value: "spot" or METERING_MODE_XXX constants. Read/write.
+    static const char KEY_METERING_MODE[];
+
     // Value for KEY_ZOOM_SUPPORTED or KEY_SMOOTH_ZOOM_SUPPORTED.
     static const char TRUE[];
 
@@ -347,6 +351,15 @@ public:
     // callback will be only called once as soon as the picture is in focus.
     static const char FOCUS_MODE_CONTINUOUS[];
 
+    // The camera determines the exposure by giving more weight to the
+    // central part of the scene.
+    static const char METERING_MODE_CENTER_WEIGHTED[];
+    // The camera determines the exposure by averaging the entire scene,
+    // giving no weighting to any particular area.
+    static const char METERING_MODE_FRAME_AVERAGE[];
+    // The camera determines the exposure by a very small area of the scene,
+    // typically the center.
+    static const char METERING_MODE_SPOT[];
 
 private:
     DefaultKeyedVector<String8,String8>    mMap;
diff --git a/libs/camera/CameraParameters.cpp b/libs/camera/CameraParameters.cpp
index e4d5bb3..c11d18f 100644
--- a/libs/camera/CameraParameters.cpp
+++ b/libs/camera/CameraParameters.cpp
@@ -71,6 +71,7 @@ const char CameraParameters::KEY_ZOOM_SUPPORTED[] = "zoom-supported";
 const char CameraParameters::KEY_SMOOTH_ZOOM_SUPPORTED[] = "smooth-zoom-supported";
 const char CameraParameters::KEY_FOCUS_DISTANCES[] = "focus-distances";
 const char CameraParameters::KEY_VIDEO_FRAME_FORMAT[] = "video-frame-format";
+const char CameraParameters::KEY_METERING_MODE[] = "metering-mode";
 
 const char CameraParameters::TRUE[] = "true";
 const char CameraParameters::FOCUS_DISTANCE_INFINITY[] = "Infinity";
@@ -142,6 +143,11 @@ const char CameraParameters::FOCUS_MODE_FIXED[] = "fixed";
 const char CameraParameters::FOCUS_MODE_EDOF[] = "edof";
 const char CameraParameters::FOCUS_MODE_CONTINUOUS[] = "continuous";
 
+// Values for metering mode settings.
+const char METERING_MODE_CENTER_WEIGHTED[] = "center-weighted";
+const char METERING_MODE_FRAME_AVERAGE[] = "frame-average";
+const char METERING_MODE_SPOT[] = "spot";
+
 CameraParameters::CameraParameters()
                 : mMap()
 {