Visualization
=============

The visualization tab provides a series of options for visualizing the object
tracks. The color of each track can be based on:

1. ``Constant`` - Constant color for all tracks, selected with the ``Constant
   color`` button.
2. ``Track`` - A random color from the ``Color Map`` is chosen for each track.
3. ``Velocity`` - A color based on the ``x`` velocity, ``y`` velocity, or
   ``magnitude`` of the velocity, the selected ``Color Map``, and the selected
   ``Range``.

The number of points of each track can be changed with the ``Point history``
spinner. To show every point of every track, no matter what frame is currently
displayed, un-check the ``Only show tracks with point in frame`` check box.

The points of the track can be displayed by selecting the ``Show points``
check-box. The size of the point can be changed using the ``Point radius``
spinner. The edge of the points can be changed using the ``Edge width``
spinner where a value of ``-1`` will remove the edge. The points can be filled
by selecting the ``Fill`` check-box. Finally, the points can fade out as the
point gets further away from the current frame by selecting the ``Fade out``
check-box.

Lines can be drawn through points by selecting the ``Show Lines`` check-box. The
width of the lines can be changed using the ``Line width`` spinner.

.. image:: ../gifs/visual.gif
    :align: center

To see the search areas (radius) of the poly-projection algorithm, select the
``Show search`` check-box. The width of the line and the style of the line (
solid, dash, or dot) can be changed using the ``Edge width`` spinner and
``Edge style`` drop-down list.

When using multi-threading or multi-processing with more than 1 worker, the
domain decomposition can be displayed by selecting the ``Show domain
decomposition`` check-box. The color and transparency of the tile edges can be
changed by using the ``Color`` button and the ``Transparency`` spinner.

Finally, images of the currently displayed frame can be saved by selecting the
``Save image stack`` check-box. As the frames are traversed, by either pressing
play or the forward and backward buttons, the frames will automatically be saved
in the directory specified in the ``Path`` line-edit. The ``Browse`` button can
be used to browse to a directory. The name of the saved images can be changed
using the `Prefix` line-edit. A zero-padded integer corresponding to the frame
will be automatically added after the prefix. The saved images can be scaled
using the ``Scale`` spinner, which is a multiplier on the number of pixels. See
:ref:`ffmpeg_cmds` for turning the image stack into a video using FFMPEG.