chrome/utility/media_galleries/image_metadata_extractor.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_UTILITY_MEDIA_GALLERIES_IMAGE_METADATA_EXTRACTOR_H_
   6 #define CHROME_UTILITY_MEDIA_GALLERIES_IMAGE_METADATA_EXTRACTOR_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/callback_forward.h"
  12 #include "base/memory/ref_counted.h"
  13
  14 namespace media {
  15 class DataSource;
  16 }
  17
  18 namespace net {
  19 class DrainableIOBuffer;
  20 }
  21
  22 namespace metadata {
  23
  24 // Extracts a basic set of image metadata tags. Users must initialize the
  25 // library before use. Each class instance is 'one-time-use', and cannot be used
  26 // to extract metadata from multiple images.
  27 class ImageMetadataExtractor {
  28  public:
  29   typedef base::Callback<void(bool)> DoneCallback;
  30
  31   // One of these two is required before use of this class.
  32   static bool InitializeLibrary();
  33   static bool InitializeLibraryForTesting();
  34
  35   ImageMetadataExtractor();
  36   ~ImageMetadataExtractor();
  37
  38   // |callback| called with whether or not the extraction succeeded. Should
  39   // only be called once.
  40   void Extract(media::DataSource* source, const DoneCallback& callback);
  41
  42   // All below methods require Extract to have already succeeded.
  43   // Returns -1 if file does not define a width or height.
  44   int width() const;
  45   int height() const;
  46
  47   // In degrees.
  48   int rotation() const;
  49
  50   // In pixels per inch.
  51   double x_resolution() const;
  52   double y_resolution() const;
  53
  54   // In the same string form as the original file.
  55   const std::string& date() const;
  56
  57   const std::string& camera_make() const;
  58   const std::string& camera_model() const;
  59   double exposure_time_sec() const;
  60   bool flash_fired() const;
  61   double f_number() const;
  62   double focal_length_mm() const;
  63   int iso_equivalent() const;
  64
  65  private:
  66   // Second half of the Extract method.
  67   void FinishExtraction(const DoneCallback& callback,
  68                         const scoped_refptr<net::DrainableIOBuffer>& buffer);
  69
  70   bool extracted_;
  71
  72   int width_;
  73   int height_;
  74
  75   int rotation_;
  76
  77   double x_resolution_;
  78   double y_resolution_;
  79
  80   std::string date_;
  81
  82   std::string camera_make_;
  83   std::string camera_model_;
  84   double exposure_time_sec_;
  85   bool flash_fired_;
  86   double f_number_;
  87   double focal_length_mm_;
  88   int iso_equivalent_;
  89
  90   DISALLOW_COPY_AND_ASSIGN(ImageMetadataExtractor);
  91 };
  92
  93 }  // namespace metadata
  94
  95 #endif  // CHROME_UTILITY_MEDIA_GALLERIES_IMAGE_METADATA_EXTRACTOR_H_