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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.media;
     18 
     19 import android.hardware.Camera;
     20 import android.hardware.Camera.CameraInfo;
     21 
     22 import java.util.Arrays;
     23 import java.util.HashMap;
     24 
     25 /**
     26  * The CameraProfile class is used to retrieve the pre-defined still image
     27  * capture (jpeg) quality levels (0-100) used for low, medium, and high
     28  * quality settings in the Camera application.
     29  *
     30  */
     31 public class CameraProfile
     32 {
     33     /**
     34      * Define three quality levels for JPEG image encoding.
     35      */
     36     /*
     37      * Don't change the values for these constants unless getImageEncodingQualityLevels()
     38      * method is also changed accordingly.
     39      */
     40     public static final int QUALITY_LOW    = 0;
     41     public static final int QUALITY_MEDIUM = 1;
     42     public static final int QUALITY_HIGH   = 2;
     43 
     44     /*
     45      * Cache the Jpeg encoding quality parameters
     46      */
     47     private static final HashMap<Integer, int[]> sCache = new HashMap<Integer, int[]>();
     48 
     49     /**
     50      * Returns a pre-defined still image capture (jpeg) quality level
     51      * used for the given quality level in the Camera application for
     52      * the first back-facing camera on the device. If the device has no
     53      * back-facing camera, this returns 0.
     54      *
     55      * @param quality The target quality level
     56      */
     57     public static int getJpegEncodingQualityParameter(int quality) {
     58         int numberOfCameras = Camera.getNumberOfCameras();
     59         CameraInfo cameraInfo = new CameraInfo();
     60         for (int i = 0; i < numberOfCameras; i++) {
     61             Camera.getCameraInfo(i, cameraInfo);
     62             if (cameraInfo.facing == CameraInfo.CAMERA_FACING_BACK) {
     63                 return getJpegEncodingQualityParameter(i, quality);
     64             }
     65         }
     66         return 0;
     67     }
     68 
     69     /**
     70      * Returns a pre-defined still image capture (jpeg) quality level
     71      * used for the given quality level in the Camera application for
     72      * the specified camera.
     73      *
     74      * @param cameraId The id of the camera
     75      * @param quality The target quality level
     76      */
     77     public static int getJpegEncodingQualityParameter(int cameraId, int quality) {
     78         if (quality < QUALITY_LOW || quality > QUALITY_HIGH) {
     79             throw new IllegalArgumentException("Unsupported quality level: " + quality);
     80         }
     81         synchronized (sCache) {
     82             int[] levels = sCache.get(cameraId);
     83             if (levels == null) {
     84                 levels = getImageEncodingQualityLevels(cameraId);
     85                 sCache.put(cameraId, levels);
     86             }
     87             return levels[quality];
     88         }
     89     }
     90 
     91     static {
     92         System.loadLibrary("media_jni");
     93         native_init();
     94     }
     95 
     96     private static int[] getImageEncodingQualityLevels(int cameraId) {
     97         int nLevels = native_get_num_image_encoding_quality_levels(cameraId);
     98         if (nLevels != QUALITY_HIGH + 1) {
     99             throw new RuntimeException("Unexpected Jpeg encoding quality levels " + nLevels);
    100         }
    101 
    102         int[] levels = new int[nLevels];
    103         for (int i = 0; i < nLevels; ++i) {
    104             levels[i] = native_get_image_encoding_quality_level(cameraId, i);
    105         }
    106         Arrays.sort(levels);  // Lower quality level ALWAYS comes before higher one
    107         return levels;
    108     }
    109 
    110     // Methods implemented by JNI
    111     private static native final void native_init();
    112     private static native final int native_get_num_image_encoding_quality_levels(int cameraId);
    113     private static native final int native_get_image_encoding_quality_level(int cameraId, int index);
    114 }
    115