This SlackBuild is intended for the few applications requiring a
version of OpenCV no greater than v3.1.0. It is NOT recommended
to install this version alongside the normal opencv package.

OpenCV (Open Source Computer Vision Library) is an open source
computer vision and machine learning software library.
OpenCV was built to provide a common infrastructure for
computer vision applications and to accelerate the use of
machine perception in commercial products.

OpenCV will incorporate features from a wide range of additional
software that may exist on the host system at build time. The more
of the relevant software packages that are available, the greater
the feature set available in the resulting OpenCV package. The
additional optional packages will mostly be autodetected and used
at build time without any user intervention. Packages that are
processed in this way include (by SBo package name):
    qt5 libdc1394 ffmpeg hdf5 VTK jdk apache-ant numpy python3 numpy3

In the unlikely situation that features from these packages are not
wanted despite already being installed on the host system,
incorporation of some of them into OpenCV may be suppressed by setting
the appropriate environment variable to "no" e.g.
    CVFFMPEG=no ./opencv-legacy.SlackBuild
Features that may be excluded in this manner are controlled by the
following environment variables:
    CV1394 CVFFMPEG CVVTK

At least one optional package is not autodetected, even though the
necessary prerequisite software may already have been installed. It
must therefore be explicitly enabled by setting the appropriate
environment variable:
    CVGDAL=yes ./opencv-legacy.SlackBuild
(to support SBo's gis/gdal)

Please note that some combinations of options may not be possible. In
particular, if both qt5 and VTK are installed on the host build system,
VTK support will be disabled unless it was built with qt5 support (which
is possible but not its default). Conversely, if VTK has been built with
qt5, it will be disabled in OpenCV unless it too is being built with qt5.

Documentation is generated by the SlackBuild unless it is switched off
by setting the CVDOCS environment variable i.e.
    CVDOCS=no ./opencv-legacy.SlackBuild
The graphviz package is an optional dependency for enhanced
documentation.