ppapi/cpp/private/image_capture_private.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
   6 #ifndef PPAPI_CPP_PRIVATE_IMAGE_CAPTURE_PRIVATE_H_
   7 #define PPAPI_CPP_PRIVATE_IMAGE_CAPTURE_PRIVATE_H_
   8
   9 #include "ppapi/c/private/ppb_image_capture_private.h"
  10 #include "ppapi/cpp/completion_callback.h"
  11 #include "ppapi/cpp/private/camera_capabilities_private.h"
  12 #include "ppapi/cpp/private/image_capture_config_private.h"
  13 #include "ppapi/cpp/resource.h"
  14 #include "ppapi/cpp/var.h"
  15
  16 /// @file
  17 /// Defines the <code>ImageCapture_Private</code> interface. Used for
  18 /// acquiring a single still image from a camera source.
  19 namespace pp {
  20
  21 /// To capture a still image with this class, use the following steps.
  22 /// 1. Create an ImageCapture_Private object by the constructor.
  23 /// 2. Call GetCameraCapabilities to get the supported preview sizes.
  24 /// 3. For optimal performance, set one of the supported preview size as the
  25 ///    constraints of getUserMedia. Use the created MediaStreamVideoTrack for
  26 ///    camera previews.
  27 /// 4. Set the same preview size and other settings by SetConfig.
  28 /// 5. Call CaptureStillImage to capture a still image. Play the shutter sound
  29 ///    in the shutter callback. The image from the preview callback can be used
  30 ///    for display. JPEG image will be returned to the JPEG callback.
  31 class ImageCapture_Private {
  32  public:
  33   /// Default constructor for creating an is_null()
  34   /// <code>ImageCapture_Private</code> object.
  35   ImageCapture_Private();
  36
  37   /// Creates an ImageCapture_Private resource.
  38   ///
  39   /// @param[in] instance A <code>PP_Instance</code> identifying one instance
  40   /// of a module.
  41   /// @param[in] camera_source_id A <code>Var</code> identifying a camera
  42   /// source. The type is string. The ID can be obtained from
  43   /// MediaStreamTrack.getSources() or MediaStreamVideoTrack.id. If a
  44   /// MediaStreamVideoTrack is associated with the same source and the track
  45   /// is closed, this ImageCapture_Private object can still do image capture.
  46   /// @param[in] error_callback A <code>ImageCapture_Private_ErrorCallback
  47   /// </code> callback to indicate the image capture has failed.
  48   /// @param[inout] user_data An opaque pointer that will be passed to the
  49   /// callbacks of ImageCapture_Private.
  50   ImageCapture_Private(const InstanceHandle& instance,
  51                        const Var& camera_source_id,
  52                        PPB_ImageCapture_Private_ErrorCallback error_callback,
  53                        void* user_data);
  54
  55   /// Constructs a <code>ImageCapture_Private</code> from a <code>
  56   /// Resource</code>.
  57   ///
  58   /// @param[in] resource A <code>ImageCapture_Private</code>
  59   /// resource.
  60   explicit ImageCapture_Private(const Resource& resource);
  61
  62   /// A constructor used when you have received a <code>PP_Resource</code> as a
  63   /// return value that has had 1 ref added for you.
  64   ///
  65   /// @param[in] resource A <code>ImageCapture_Private</code>
  66   /// resource.
  67   ImageCapture_Private(PassRef, PP_Resource resource);
  68
  69   // Destructor.
  70   ~ImageCapture_Private();
  71
  72   /// Disconnects from the camera and cancels all pending capture requests.
  73   /// After this returns, no callbacks will be called. If <code>
  74   /// ImageCapture_Private</code> is destroyed and is not closed yet, this
  75   /// function will be automatically called. Calling this more than once has no
  76   /// effect.
  77   ///
  78   /// @param[in] callback <code>CompletionCallback</code> to be called upon
  79   /// completion of <code>Close()</code>.
  80   ///
  81   /// @return An int32_t containing a result code from <code>pp_errors.h</code>.
  82   int32_t Close(const CompletionCallback& callback);
  83
  84   /// Sets the configuration of the image capture.
  85   /// If <code>SetConfig()</code> is not called, default settings will be used.
  86   ///
  87   /// @param[in] config A <code>ImageCaptureConfig_Private</code> object.
  88   /// @param[in] callback <code>CompletionCallback</code> to be called upon
  89   /// completion of <code>SetConfig()</code>.
  90   ///
  91   /// @return An int32_t containing a result code from <code>pp_errors.h</code>.
  92   /// Returns <code>PP_ERROR_INPROGRESS</code> if there is a pending call of
  93   /// <code>SetConfig()</code> or <code>CaptureStillImage()</code>.
  94   /// If an error is returned, the configuration will not be changed.
  95   int32_t SetConfig(const ImageCaptureConfig_Private& config,
  96                     const CompletionCallback& callback);
  97
  98   /// Gets the configuration of the image capture.
  99   ///
 100   /// @param[in] callback A <code>CompletionCallbackWithOutput</code>
 101   /// to be called upon completion.
 102   ///
 103   /// @return An int32_t containing a result code from <code>pp_errors.h</code>.
 104   int32_t GetConfig(
 105       const CompletionCallbackWithOutput<ImageCaptureConfig_Private>& callback);
 106
 107   /// Gets the camera capabilities.
 108   ///
 109   /// The camera capabilities do not change for a given camera source.
 110   ///
 111   /// @param[in] callback A <code>CompletionCallbackWithOutput</code>
 112   /// to be called upon completion.
 113   ///
 114   /// @return An int32_t containing a result code from <code>pp_errors.h</code>.
 115   int32_t GetCameraCapabilities(
 116       const CompletionCallbackWithOutput<CameraCapabilities_Private>& callback);
 117
 118   /// Captures a still JPEG image from the camera.
 119   ///
 120   /// Triggers an asynchronous image capture. The camera will initiate a series
 121   /// of callbacks to the application as the image capture progresses. The
 122   /// callbacks will be invoked in the order of shutter callback, preview
 123   /// callback, and JPEG callback. The shutter callback occurs after the image
 124   /// is captured. This can be used to trigger a sound to let the user know that
 125   /// image has been captured. The preview callback occurs when a scaled, fully
 126   /// processed preview image is available. The JPEG callback occurs when the
 127   /// compressed image is available. If there is an error after the capture is
 128   /// in progress, the error callback passed to <code>
 129   /// ImageCapture_Private.Create()</code> will be invoked. All the callbacks
 130   /// are invoked by the thread that calls this function.
 131   ///
 132   /// The size of the preview image in preview callback is determined by
 133   /// <code>ImageCaptureConfig_Private.SetPreviewSize</code>. The format is
 134   /// decided by the camera and can be got from <code>VideoFrame.GetFormat
 135   /// </code>. The size of the JPEG image is determined by <code>
 136   /// ImageCaptureConfig_Private.SetJpegSize</code>.
 137   ///
 138   /// The camera may need to stop and re-start streaming during image capture.
 139   /// If some MediaStreamVideoTrack are associated with the camera source, they
 140   /// will receive mute and unmute events. The mute event will be received
 141   /// before all the callbacks. The unmute event will be received after all the
 142   /// callbacks. The preview image will not be sent to the video tracks
 143   /// associated with the camera.
 144   ///
 145   /// @param[in] shutter_callback A <code>
 146   /// ImageCapture_Private_ShutterCallback</code> callback to indicate the
 147   /// image has been taken.
 148   /// @param[in] preview_callback A <code>
 149   /// ImageCapture_Private_PreviewCallback</code> callback to return a
 150   /// preview of the captured image.
 151   /// @param[in] jpeg_callback A <code>
 152   /// ImageCapture_Private_JpegCallback</code> callback to return captured
 153   /// JPEG image.
 154   /// @param[out] sequence_id The sequence ID is a unique monotonically
 155   /// increasing value starting from 0, incremented every time a new request
 156   /// like image capture is submitted.
 157   ///
 158   /// @return An int32_t containing a result code from <code>pp_errors.h</code>.
 159   /// PP_OK means the callbacks will be triggered. Other values mean the
 160   /// callbacks will not be triggered.
 161   int32_t CaptureStillImage(
 162       PPB_ImageCapture_Private_ShutterCallback shutter_callback,
 163       PPB_ImageCapture_Private_PreviewCallback preview_callback,
 164       PPB_ImageCapture_Private_JpegCallback jpeg_callback,
 165       int64_t* sequence_id);
 166
 167   /// Determines if a resource is an image capture resource.
 168   ///
 169   /// @param[in] resource The <code>Resource</code> to test.
 170   ///
 171   /// @return true if the given resource is an image capture resource or false
 172   /// otherwise.
 173   static bool IsImageCapture(const Resource& resource);
 174 };
 175
 176 } // namespace pp
 177
 178 #endif  /* PPAPI_CPP_PRIVATE_IMAGE_CAPTURE_PRIVATE_H_ */
 179