Source code for camera

"""Camera module.

This module handles various backends (different for every OS) for streaming the video from a (web)camera.
"""

import os

if os.name == 'posix':
    
    import Image
    import cv

    class Camera:
        """Implement basic camera capabilities
        
        This class has different implementations for different OS. On posix
        systems it calls to opencv, on Windows to VideoCapture."""
        # TODO what about win 64?
        # TODO why not openCV on win?
        # TODO document VideoCapture as a dependency
        def __init__(self, vid=0, res=None):
            self._cam = cv.CreateCameraCapture(vid)
            if res:
                cv.SetCaptureProperty(self._cam, cv.CV_CAP_PROP_FRAME_WIDTH, res[0])
                cv.SetCaptureProperty(self._cam, cv.CV_CAP_PROP_FRAME_HEIGHT,
                                      res[1])

        def get_image(self):
            """Get a new image from the camera."""
            for _ in range(5): #HACK TODO document this
                im = cv.QueryFrame(self._cam)
            return Image.fromstring("RGB", cv.GetSize(im), im.tostring(), "raw",
                                    "BGR", 0, 1) 
        
        def __del__(self):
            del self._cam 


elif os.name in ('ce', 'nt', 'dos'):
    
    from VideoCapture import Device

    # TODO exception handling
    class Camera:
        def __init__(self):
            self._cam = Device()
            self._cam.setResolution(640, 480)

        def get_image(self):
            return self._cam.getImage()

        def __del__(self):
            del self._cam

else:
    pass # TODO exception "Cannot recognise OS." or back to posix?