<meter>

Description

Similar in function to matrix metering on your camera, the meter nodes look into the current scene and calculate a single value from certain metering layers within the image nodes currently in the view. This value can be fed into a behavior node. The value can be used to set the blend of a layer to create Adaptive Dynamic Range type applications.

behavior nodes can either be referenced by id, or included as a child to the meter node.

Syntax

<tour>
  <scene>
    <panoelement id="nodeID" ...\>
    ...

    <meter id="meterID" behavior="someBehavior" 
      class="meterLayer" meterspots="5" distribution=".5" 
      minvalue="0" maxvalue="100" />
    ...
  </scene>
  ...

</tour>

Attributes

• id

  Unique id to reference the meter by.

• class

  The class of layer to meter. The meter node can meter visible layers (such as the 'base' layer of an image), or invisible layers (ie: layers with classes other than 'base', 'hover', 'press' or 'disabled'). For most applications it makes sense to add a new class of layers to the images you want to meter.
  RGB values are converted to greyscale to yield a single value.

• active

  Turns the signal on or off.
  Values: true or false, defaults to false

• spots

  Specifies the number of spots used for metering. The spots patterns are akin to metering spots in a camera.
  Values:

  • 1

    	[ ]

  • 2

    [ ]		[ ]

  • 3

    [ ]	[ ]	[ ]

  • 4

    	[ ]
    [ ]		[ ]
    	[ ]

  • 5

    	[ ]
    [ ]	[ ]	[ ]
    	[ ]

  • 6

    		[ ]
    [ ]	[ ]		[ ]	[ ]
    		[ ]

  • 9

    [ ]	[ ]	[ ]
    [ ]	[ ]	[ ]
    [ ]	[ ]	[ ]

• distribution

  Specifies how much of the view the meter spots cover. Higher values result in a wider metering coverage, lower values give more localised results.
  Setting distribution to 0 effectively sets spots to 0. Ignored if only 1 spot is used.
  0 to 1, defaults to 0.5 (half of the view)

• pointerweight

  Normally the metering spots are around the center of the view. By setting the pointerweight to 1, the center of spot metering follows the mouse pointer instead. Values between 0 and 1 will have the center of metering in between the center of the view and the mouse location.
  Values: 0 to 1, defaults to 0

• minvalue

  Specifies the lower limit of the metered value.
  Values: numeric, defaults to 0

• maxvalue

  Specifies the upper limit of the metered value.
  Values: numeric, defaults to 100

• defaultvalue

  The default value to use for each spot if the spot does not 'touch' any elements with the specified class.
  Values: numeric, between minvalue and maxvalue

• maxstep

  Controls the maximum step on each iteration for value to reach its destination value (either value1 or value2 effectively setting the maximum steepness of the signal.
  Values: >0

• stepincrease

  Dampens the step on each iteration. The step value is increased on each iteration until it reaches maxstep (if specified) or until step needs to decrease to smoothly reach its destination.
  Values: >0

Events

• change

  Fired when the metered value has changed.

Children

• behavior

History

• 27-Nov-05: dispersion -> distribution
• 17-Oct-05: Added attributes, events
• 03-Aug-04: Initial version