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.. module:: NatronEngine

Effect

Inherits: :doc:`Group` , :doc:`UserParamHolder`

Synopsis

This object represents a single node in Natron, that is: an instance of a plug-in. See :ref:`Effectdetails`

Functions

Detailed Description

The Effect object can be used to operate with a single node in Natron. To create a new Effect, use the :func:`app.createNode(pluginID)<NatronEngine.App.createNode>` function.

Natron automatically declares a variable to Python when a new Effect is created. This variable will have a script-name determined by Natron as explained in the :ref:`autovar` section.

Once an Effect is instantiated, it declares all its :doc:`Param` and inputs. See how to :ref:`manage <userParams>` user parameters below

To get a specific :doc:`Param` by script-name, call the :func:`getParam(name) <NatronEngine.Effect.getParam>` function

Input effects are mapped against a zero-based index. To retrieve an input Effect given an index, you can use the :func:`getInput(inputNumber) <NatronEngine.Effect.getInput>` function.

To manage inputs, you can connect them and disconnect them with respect to their input index with the :func:`connectInput(inputNumber,input)<NatronEngine.Effect.connectInput>` and then :func:`disconnectInput(inputNumber)<NatronEngine.Effect.disconnectInput>` functions.

If you need to destroy permanently the Effect, just call :func:`destroy() <NatronEngine.Effect.destroy()>`.

For convenience some GUI functionalities have been made accessible via the Effect class to control the GUI of the node (on the node graph):

Creating user parameters

See :ref:`this section<userParams.details>`

Member functions description

.. method:: NatronEngine.Effect.addUserPlane(planeName,channels)

    :param planeName: :class:`str<NatronEngine.std::string>`
    :param channels: :class:`sequence`
    :rtype: :class:`bool<PySide.QtCore.bool>`

    Adds a new plane to the Channels selector of the node in its settings panel. When selected,
    the end-user can choose to output the result of the node to this new custom plane.
    The *planeName* will identify the plane uniquely and must not contain spaces or non
    python compliant characters.
    The *channels* are a sequence of channel names, e.g.:

        addUserPlane("MyLayer",["R", "G", "B", "A"])

    .. note::

        A plane cannot contain more than 4 channels and must at least have 1 channel.

    This function returns *True* if the layer was added successfully, *False* otherwise.


.. method:: NatronEngine.Effect.beginChanges()

    Starts a begin/End bracket, blocking all evaluation (=renders and callback onParamChanged) that would be issued due to
    a call to :func:`setValue<NatronEngine.IntParam.setValue>` on any parameter of the Effect.

    Similarly all input changes will not be evaluated until endChanges() is called.

    Typically to change several values at once we bracket the changes like this::

        node.beginChanges()
        param1.setValue(...)
        param2.setValue(...)
        param3.setValue(...)
        param4.setValue(...)
        node.endChanges()  # This triggers a new render

    A more complex call:

        node.beginChanges()
        node.connectInput(0,otherNode)
        node.connectInput(1,thirdNode)
        param1.setValue(...)
        node.endChanges() # This triggers a new render



.. method:: NatronEngine.Effect.endChanges()

    Ends a begin/end bracket. If the begin/end bracket recursion reaches 0 and there were calls
    made to :func:`setValue<NatronEngine.IntParam.setValue>` this function will effectively compresss
    all evaluations into a single one.
    See :func:`beginChanges()<NatronEngine.Effect.beginChanges>`






.. method:: NatronEngine.Effect.canConnectInput(inputNumber, node)


    :param inputNumber: :class:`int<PySide.QtCore.int>`
    :param node: :class:`Effect<NatronEngine.Effect>`
    :rtype: :class:`bool<PySide.QtCore.bool>`

Returns whether the given node can be connected at the given inputNumber of this Effect. This function could return False for one of the following reasons:

  • The Effect already has an input at the given inputNumber
  • The node is None
  • The given inputNumber is out of range
  • The node cannot have any node connected to it (such as a BackDrop or an Output)
  • This Effect or the given node is a child of another node (for trackers only)
  • Connecting node would create a cycle in the graph implying that it would create infinite recursions
.. method:: NatronEngine.Effect.connectInput(inputNumber, input)


    :param inputNumber: :class:`int<PySide.QtCore.int>`
    :param input: :class:`Effect<NatronEngine.Effect>`
    :rtype: :class:`bool<PySide.QtCore.bool>`

Connects input to the given inputNumber of this Effect. This function calls internally :func:`canConnectInput()<NatronEngine.Effect.canConnectInput>` to determine if a connection is possible.

.. method:: NatronEngine.Effect.destroy([autoReconnect=true])


    :param autoReconnect: :class:`bool<PySide.QtCore.bool>`

Removes this Effect from the current project definitively. If autoReconnect is True then any nodes connected to this node will try to connect their input to the input of this node instead.

.. method:: NatronEngine.Effect.disconnectInput(inputNumber)


    :param inputNumber: :class:`int<PySide.QtCore.int>`

Removes any input Effect connected to the given inputNumber of this node.

.. method:: NatronEngine.Effect.getAvailableLayers()

    :rtype: :class:`dict`

    Returns the layer available on this node. This is a dict with a :class:`ImageLayer<NatronEngine.ImageLayer>`
    as key and :class:`Effect<NatronEngine.Effect>` as value. The Effect is the closest node in
    the upstream tree (including this node) that produced that layer.

    For example, in a simple graph Read --> Blur, if the Read node has a layer available
    named "RenderLayer.combined" but Blur is set to process only the color layer (RGBA), then
    calling this function on the Blur will return a dict containing for key "RenderLayer.combined"
    the Read node, whereas the dict will have for the key "RGBA" the Blur node.


.. method:: NatronEngine.Effect.getBitDepth()

    :rtype: :class:`ImageBitDepthEnum<NatronEngine.Natron.ImageBitDepthEnum>`

    Returns the bit-depth of the image in output of this node.


.. method:: NatronEngine.Effect.getColor()

    :rtype: :class:`tuple`

Returns the color of this node as it appears on the node graph as [R,G,B] 3-dimensional tuple.

.. method:: NatronEngine.Effect.getCurrentTime()


    :rtype: :class:`int<PySide.QtCore.int>`

Returns the current time of timeline if this node is currently rendering, otherwise it returns the current time at which the node is currently rendering for the caller thread.

.. method:: NatronEngine.Effect.getOutputFormat()

    :rtype: :class:`RectI<NatronEngine.RectI>`

    Returns the output format of this node in pixel units.



.. method:: NatronEngine.Effect.getFrameRate()

    :rtype: :class:`float<PySide.QtCore.float>`

    Returns the frame-rate of the sequence in output of this node.


.. method:: NatronEngine.Effect.getInput(inputNumber)


    :param inputNumber: :class:`int<PySide.QtCore.int>`
    :rtype: :class:`Effect<NatronEngine.Effect>`

    Returns the node connected at the given *inputNumber*.



.. method:: NatronEngine.Effect.getInput(inputName)
param inputName:

:class:`str<PySide.QtCore.QString>`
rtype:

:class:`Effect<NatronEngine.Effect>`

Same as :func:`getInput(inputNumber)<NatronEngine.Effect.getInput>` except that the parameter in input is the name of the input as displayed on the node-graph. This function is made available for convenience.

 
.. method:: NatronEngine.Effect.getLabel()


    :rtype: :class:`str<NatronEngine.std::string>`

Returns the label of the node. See :ref:`this section<autoVar>` for a discussion of the label vs the script-name.

.. method:: NatronEngine.Effect.getInputLabel(inputNumber)


    :param inputNumber: :class:`int<PySide.QtCore.int>`
    :rtype: :class:`str<NatronEngine.std::string>`

Returns the label of the input at the given inputNumber. It corresponds to the label displayed on the arrow of the input in the node graph.

.. method:: NatronEngine.Effect.getMaxInputCount()


    :rtype: :class:`int<PySide.QtCore.int>`

Returns the number of inputs for the node. Graphically this corresponds to the number of arrows in input.

.. method:: NatronEngine.Effect.getParam(name)


    :param name: :class:`str<NatronEngine.std::string>`
    :rtype: :class:`Param<Param>`

Returns a :doc:`parameter<Param>` by its script-name or None if no such parameter exists.

.. method:: NatronEngine.Effect.getParams()


    :rtype: :class:`sequence`

Returns all the :class:`Param<NatronEngine.Param>` of this Effect as a sequence.

.. method:: NatronEngine.Effect.getPluginID()


    :rtype: :class:`str<NatronEngine.std::string>`

Returns the ID of the plug-in that this node instantiate.

.. method:: NatronEngine.Effect.getPosition()


    :rtype: :class:`tuple`

Returns the current position of the node on the node-graph. This is a 2 dimensional [X,Y] tuple. Note that in background mode, if used, this function will always return [0,0] and should NOT be used.

.. method:: NatronEngine.Effect.getPremult()

    :rtype: :class:`ImagePremultiplicationEnum<NatronEngine.Natron.ImagePremultiplicationEnum>`

    Returns the alpha premultiplication state of the image in output of this node.


.. method:: NatronEngine.Effect.getPixelAspectRatio()

    :rtype: :class:`float<PySide.QtCore.float>`

    Returns the pixel aspect ratio of the image in output of this node.




.. method:: NatronEngine.Effect.getRegionOfDefinition(time,view)

    :param time: :class:`float<PySide.QtCore.float>`
    :param view: :class:`int<PySide.QtCore.int>`
    :rtype: :class:`RectD<NatronEngine.RectD>`

Returns the bounding box of the image produced by this effect in canonical coordinates. This is exactly the value displayed in the "Info" tab of the settings panel of the node for the "Output". This can be useful for example to set the position of a point parameter to the center of the region of definition.

.. method:: NatronEngine.Effect.getRotoContext()


    :rtype: :class:`Roto<NatronEngine.Roto>`

Returns the roto context for this node. Currently only the Roto node has a roto context. The roto context is in charge of maintaining all information relative to :doc:`Beziers<BezierCurve>` and :doc:`Layers<Layer>`. Most of the nodes don't have a roto context though and this function will return None.

.. method:: NatronEngine.Effect.getTrackerContext()


    :rtype: :class:`Tracker<NatronEngine.Tracker>`

Returns the tracker context for this node. Currently only the Tracker node has a tracker context. The tracker context is in charge of maintaining all information relative to :doc:`Tracks<Track>`. Most of the nodes don't have a tracker context though and this function will return None.

.. method:: NatronEngine.Effect.getScriptName()


    :rtype: :class:`str<NatronEngine.std::string>`

Returns the script-name of this Effect. See :ref:`this<autoVar>` section for more information about the script-name.

.. method:: NatronEngine.Effect.getSize()

    :rtype: :class:`tuple`

Returns the size of this node on the node-graph as a 2 dimensional [Width,Height] tuple. Note that calling this function will in background mode will always return [0,0] and should not be used.

.. method:: NatronEngine.Effect.getUserPageParam()


    :rtype: :class:`PageParam<NatronEngine.PageParam>`

Convenience function to return the user page parameter if this Effect has one.

.. method:: NatronEngine.Effect.isUserSelected()


    :rtype: :class:`bool<PySide.QtCore.bool>`


    Returns true if this node is selected in its containing nodegraph.



.. method:: NatronEngine.Effect.isReaderNode()

    :rtype: :class:`bool<PySide.QtCore.bool>`


    Returns True if this node is a reader node




.. method:: NatronEngine.Effect.isWriterNode()

    :rtype: :class:`bool<PySide.QtCore.bool>`


    Returns True if this node is a writer node


.. method:: NatronEngine.Effect.isOutputNode()

    :rtype: :class:`bool<PySide.QtCore.bool>`


    Returns True if this node is an output node (which also means that it has no output)


.. method:: NatronEngine.Effect.setColor(r, g, b)


    :param r: :class:`float<PySide.QtCore.double>`
    :param g: :class:`float<PySide.QtCore.double>`
    :param b: :class:`float<PySide.QtCore.double>`

Set the color of the node as it appears on the node graph. Note that calling this function will in background mode will do nothing and should not be used.

.. method:: NatronEngine.Effect.setLabel(name)


    :param name: :class:`str<NatronEngine.std::string>`

Set the label of the node as it appears in the user interface. See :ref:`this<autoVar>` section for an explanation of the difference between the label and the script-name.

.. method:: NatronEngine.Effect.setPosition(x, y)


    :param x: :class:`float<PySide.QtCore.double>`
    :param y: :class:`float<PySide.QtCore.double>`

Set the position of the node as it appears on the node graph. Note that calling this function will in background mode will do nothing and should not be used.

.. method:: NatronEngine.Effect.setScriptName(scriptName)


    :param scriptName: :class:`str<NatronEngine.std::string>`
    :rtype: :class:`bool<PySide.QtCore.bool>`

Set the script-name of the node as used internally by Natron. See :ref:`this<autoVar>` section for an explanation of the difference between the label and the script-name.

Warning

Using this function will remove any previous variable declared using the old script-name and will create a new variable with the new script name if valid.

If your script was using for instance a node named:

app1.Blur1

and you renamed it BlurOne, it should now be available to Python this way:

app1.BlurOne

but using app1.Blur1 would report the following error:

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'Blur1' is not defined

.. method:: NatronEngine.Effect.setSize(w, h)


    :param w: :class:`float<PySide.QtCore.double>`
    :param h: :class:`float<PySide.QtCore.double>`

Set the size of the node as it appears on the node graph. Note that calling this function will in background mode will do nothing and should not be used.

.. method:: NatronEngine.Effect.setSubGraphEditable(editable)

    :param editable: :class:`bool<PySide.QtCore.bool>`

Can be called to disable editing of the group via Natron's graphical user interface. This is handy to prevent users from accidentally breaking the sub-graph. This can always be reverted by editing the python script associated. The user will still be able to see the internal node graph but will not be able to unlock it.

.. method:: NatronEngine.Effect.setPagesOrder(pages)

    :param pages: :class:`sequence`

Given the string list pages try to find the corresponding pages by their-script name and order them in the given order.