Add functionality allowing one to specify camera settings via one's I…

…NI settings.

Camera.py

@@ -41,11 +41,57 @@ def __init__(self, prefix=""):
 		if cv is None: return
 		self.prefix  = prefix
 		self.idx     = Utils.getInt("Camera", prefix)
+		self.props   = self._getCameraProperties(prefix)
 		self.camera  = None
 		self.image   = None
 		self.frozen  = None
 		self.imagetk = None
 
+	def _getCameraProperties(self, prefix):
+		""" Gather user-defined camera configuration properties
+
+		Allows user to specify parameters like::
+
+		    [Camera]
+		    aligncam_height = 640
+		    aligncam_width = 480
+
+		to adjust the capture settings of the 'aligncam' camera.
+
+		:param str prefix: Prefix to gather
+		:returns: Dictionary mapping property suffix with a 2-tuple of
+			a function defining the data type, and a CV_CAP_PROP
+			property.
+		"""
+		POSSIBLE_PROPERTIES = {
+			'height': (Utils.getInt, cv.cv.CV_CAP_PROP_FRAME_HEIGHT, ),
+			'width': (Utils.getInt, cv.cv.CV_CAP_PROP_FRAME_WIDTH, ),
+			'fps': (Utils.getInt, cv.cv.CV_CAP_PROP_FPS, ),
+			'codec': (Utils.getStr, cv.cv.CV_CAP_PROP_FOURCC, ),
+			'brightness': (Utils.getInt, cv.cv.CV_CAP_PROP_BRIGHTNESS, ),
+			'contrast': (Utils.getInt, cv.cv.CV_CAP_PROP_CONTRAST, ),
+			'saturation': (Utils.getInt, cv.cv.CV_CAP_PROP_SATURATION, ),
+			'hue': (Utils.getInt, cv.cv.CV_CAP_PROP_HUE, ),
+			'gain': (Utils.getInt, cv.cv.CV_CAP_PROP_GAIN, ),
+			'exposure': (Utils.getInt, cv.cv.CV_CAP_PROP_EXPOSURE, ),
+		}
+
+		UNSPECIFIED = object()
+		properties_set = {}
+
+		for key, data in POSSIBLE_PROPERTIES.items():
+			fn, prop = data
+			value = fn(
+				'Camera',
+				'_'.join([prefix, key]),
+				default=UNSPECIFIED
+			)
+
+			if value is not UNSPECIFIED:
+				properties_set[prop] = value
+
+		return properties_set
+
 	#-----------------------------------------------------------------------
 	def isOn(self):
 		if cv is None: return False
@@ -55,6 +101,10 @@ def isOn(self):
 	def start(self):
 		if cv is None: return
 		self.camera = cv.VideoCapture(self.idx)
+
+		for prop_id, prop_value in self.props.items():
+			self.camera.set(prop_id, prop_value)
+
 		if self.camera is None: return
 		s, self.image = self.camera.read()
 		if not self.camera.isOpened():