-feComposite Filter Element

-==========================

-.. seealso:: http://www.w3.org/TR/SVG11/filters.html#feCompositeElement

-This filter performs the combination of the two input images pixel-wise in image

-space using one of the Porter-Duff compositing operations: over, in, atop, out,

-xor. Additionally, a component-wise arithmetic operation (with the result clamped

-between [0..1]) can be applied.

-The arithmetic operation is useful for combining the output from the

-**feDiffuseLighting** and **feSpecularLighting** filters with texture data.

-It is also useful for implementing dissolve. If the arithmetic operation is

-chosen, each result pixel is computed using the following formula::

- result = k1*i1*i2 + k2*i1 + k3*i2 + k4

-For this filter primitive, the extent of the resulting image might grow as

-described in the section that describes the filter primitive subregion.

-For common properties see: :ref:`filter_primitive`

-* **in** -- (see :ref:`in <in_attr>` attribute)

-* **operator** -- ``'over | in | out | atop | xor | arithmetic``

- The compositing operation that is to be performed. All of the **operator**

- types except arithmetic match the correspond operation as described in [PORTERDUFF].

- The arithmetic operator is described above. If attribute **operator** is not

- specified, then the effect is as if a value of ``'over'`` were specified.

-* **k1**, **k2**, **k3**, **k4** -- `<number>`

- Only applicable if **operator** = ``'arithmetic'``.

- If the attribute is not specified, the effect is as if a value of 0 were specified.

-* **in2** -- (see :ref:`in <in_attr>` attribute)

- The second input image to the compositing operation. This attribute can

- take on the same values as the **in** attribute.