.. meta::
:description: Kdenlive Video Effects - Alpha Gradient
:keywords: KDE, Kdenlive, video editor, help, learn, easy, effects, filter, video effects, alpha gradient
.. metadata-placeholder
:authors: - Claus Christensen
- Yuri Chornoivan
- Ttguy (https://userbase.kde.org/User:Ttguy)
- Bushuev (https://userbase.kde.org/User:Bushuev)
- Bernd Jordan (https://discuss.kde.org/u/berndmj)
:license: Creative Commons License SA 4.0
Alpha Gradient
==============
.. figure:: /images/effects_and_compositions/kdenlive2308_effects-alpha_gradient.webp
:width: 365px
:figwidth: 365px
:align: left
.. sidebar:: |kdenlive-show-video| Alpha Gradient
:**Status**:
Maintained
:**Keyframes**:
Yes
:**Source library**:
frei0r
:**Source filter**:
alphagrad
:**Available**:
|linux| |appimage| |windows| |apple|
:**On Master only**:
No
:**Known bugs**:
No
.. rst-class:: clear-both
.. rubric:: Description
Fill the alpha channel with a specified gradient (frei0r.alphagrad)\ [1]_. Its purpose is to enable, together with alpha controlled color manipulation, the use of graduated neutral-density filters similar to what one uses in photography\ [2]_.
.. rubric:: Parameters
.. list-table::
:header-rows: 1
:width: 100%
:class: table-wrap
* - Parameter
- Value
- Description
* - Operation
- Selection
- Defines the compositing operation
* - Position
- Integer
- Position where the gradient starts (range is 0-1000, default is 500)
* - Transition width
- Integer
- Width of the gradient (range is 0-1000, default is 500)
* - Tilt
- Integer
- Rotation of the gradient (range is 0-1000, default is 500). Values below 500 rotate counter clockwise, values above rotate clockwise. 0 means a rotation of -180 degrees, 1000 a rotation of +180 degrees.
* - Min
- Integer
- Sets the density at the bottom / start of the gradient (range is 0-1000, default is 0)
* - Max
- Integer
- Sets the density at the top / end of the gradient (range is 0-1000, default is 1000)
The following selection items are available:
:guilabel:`Operation`
.. list-table::
:width: 100%
:widths: 30 70
:class: table-simple
* - Write on clear
- Overlay the image (default)
* - Add
- Add the existing pixel and the calculated gradient values
* - Min
- Take the minimum of existing pixel and calculated gradient values
* - Max
- Take the maximum of existing pixel and calculated gradient values
* - Subtract
- Subtract from the existing pixel the calculated gradient value
.. rubric:: Notes
In the example below a `.png` image has been overlayed to a video clip and the Alpha Gradient effect applied with its default values. You can see how the gradient darkens the video. Note the Operation **Add** to make the text opaque.
.. figure:: /images/effects_and_compositions/kdenlive2304_effects-alpha_gradient_before.webp
:align: left
:width: 90%
:alt: kdenlive2304_effects-alpha_gradient_before
Alpha Gradient effect - before
.. figure:: /images/effects_and_compositions/kdenlive2304_effects-alpha_gradient_after.webp
:align: left
:width: 90%
:alt: kdenlive2304_effects-alpha_gradient_after
Alpha Gradient effect - after
.. rst-class:: clear-both
----
.. |wiki_graduated_nd_filter| raw:: html
graduated neutral-density filter
.. |alphaops| raw:: html
frei0r alpha0ps plugins
.. [1] The description of this effect has been taken in parts from the readme file for the |alphaops|. You find much more detailed information there.
.. [2] For more details about this topic refer to the Wikipedia entry about the |wiki_graduated_nd_filter|.