JUCE/modules/juce_video/capture/juce_CameraDevice.h

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
   27th April 2017).

   End User License Agreement: www.juce.com/juce-5-licence
   Privacy Policy: www.juce.com/juce-5-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

#if JUCE_USE_CAMERA || DOXYGEN


//==============================================================================
/**
    Controls any video capture devices that might be available.

    Use getAvailableDevices() to list the devices that are attached to the
    system, then call openDevice to open one for use. Once you have a CameraDevice
    object, you can get a viewer component from it, and use its methods to
    stream to a file or capture still-frames.
*/
class JUCE_API  CameraDevice
{
public:
    /** Destructor. */
    virtual ~CameraDevice();

    //==============================================================================
    /** Returns a list of the available cameras on this machine.

        You can open one of these devices by calling openDevice().
    */
    static StringArray getAvailableDevices();

    /** Opens a camera device.

        The index parameter indicates which of the items returned by getAvailableDevices()
        to open.

        The size constraints allow the method to choose between different resolutions if
        the camera supports this. If the resolution cam't be specified (e.g. on the Mac)
        then these will be ignored.

        On Mac, if highQuality is false, then the camera will be opened in preview mode
        which will allow the OS to drop frames if the computer cannot keep up in processing
        the frames.
    */
    static CameraDevice* openDevice (int deviceIndex,
                                     int minWidth = 128, int minHeight = 64,
                                     int maxWidth = 1024, int maxHeight = 768,
                                     bool highQuality = true);

    //==============================================================================
    /** Returns the name of this device */
    const String& getName() const noexcept          { return name; }

    /** Creates a component that can be used to display a preview of the
        video from this camera.
    */
    Component* createViewerComponent();

    //==============================================================================
    /** Starts recording video to the specified file.

        You should use getFileExtension() to find out the correct extension to
        use for your filename.

        If the file exists, it will be deleted before the recording starts.

        This method may not start recording instantly, so if you need to know the
        exact time at which the file begins, you can call getTimeOfFirstRecordedFrame()
        after the recording has finished.

        The quality parameter can be 0, 1, or 2, to indicate low, medium, or high. It may
        or may not be used, depending on the driver.
    */
    void startRecordingToFile (const File& file, int quality = 2);

    /** Stops recording, after a call to startRecordingToFile(). */
    void stopRecording();

    /** Returns the file extension that should be used for the files
        that you pass to startRecordingToFile().

        This may be platform-specific, e.g. ".mov" or ".avi".
    */
    static String getFileExtension();

    /** After calling stopRecording(), this method can be called to return the timestamp
        of the first frame that was written to the file.
    */
    Time getTimeOfFirstRecordedFrame() const;

    //==============================================================================
    /**
        Receives callbacks with images from a CameraDevice.

        @see CameraDevice::addListener
    */
    class JUCE_API  Listener
    {
    public:
        Listener() {}
        virtual ~Listener() {}

        /** This method is called when a new image arrives.

            This may be called by any thread, so be careful about thread-safety,
            and make sure that you process the data as quickly as possible to
            avoid glitching!
        */
        virtual void imageReceived (const Image& image) = 0;
    };

    /** Adds a listener to receive images from the camera.

        Be very careful not to delete the listener without first removing it by calling
        removeListener().
    */
    void addListener (Listener* listenerToAdd);

    /** Removes a listener that was previously added with addListener(). */
    void removeListener (Listener* listenerToRemove);

private:
    String name;

    struct Pimpl;
    friend struct Pimpl;
    friend struct ContainerDeletePolicy<Pimpl>;
    ScopedPointer<Pimpl> pimpl;

    struct ViewerComponent;
    friend struct ViewerComponent;

    CameraDevice (const String& name, int index,
                  int minWidth, int minHeight, int maxWidth, int maxHeight, bool highQuality);

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (CameraDevice)
};

#ifndef DOXYGEN
 /** This typedef is just for compatibility with VC6 - newer code should use the CameraDevice::Listener class directly. */
 typedef CameraDevice::Listener CameraImageListener;
#endif

#endif

} // namespace juce