The `UnitTestVTKDataSetReader` test reads in .vtk files of multiple
formats. The origins of this test predate the use of git-lfs and a data
directory, so the test defined in the source code several strings
containing the contents of the files.
That is no longer necessary. This change removes those strings from the
file and creates actual files in the data directory. This is easier to
manage as well as more convenient if you want to use the same data in a
different test or just take a look at the data in a different program
(such as VisIt or ParaView).
The testing helper class provided a method named `GetTestDataBasePath`
that returned the base path to all the data files stored in the VTK-m
repo. This is fine, but it was a little cumbersome to build filenames.
To make things easier, there is now a new method named `DataPath` that
takes a string of the filename (or, rather, subpath) to the file in that
directory and automatically builds the path to it.
As a programming convenience, all `vtkm::cont::DataSet` written by
`vtkm::io::VTKDataSetWriter` were written as a structured grid. Although
technically correct, it changed the structure of the data. This meant that
if you wanted to capture data to run elsewhere, it would run as a different
data type. This was particularly frustrating if the data of that structure
was causing problems and you wanted to debug it.
Now, `VTKDataSetWriter` checks the type of the `CoordinateSystem` to
determine whether the data should be written out as `STRUCTURED_POINTS`
(i.e. a uniform grid), `RECTILINEAR_GRID`, or `STRUCTURED_GRID`
(curvilinear).
Updated the image writer classes to better follow VTK-m naming
convention (i.e. use `ImageWriterPNG` instead of `PNGWriter`). The
structure of the image writer class now also better matches the
interface for the VTK writer.
Also put the implementation of the image writers into the `vtkm_io`
library so that it only has to be compiled once.
Updated the image reader classes to better follow VTK-m naming
convention (i.e. use `ImageReaderPNG` instead of `PNGReader`).
The structure of the image reader class now also better matches
the interface for the VTK reader.
Also put the implementation of the image readers into the `vtkm_io`
library so that it only has to be compiled once.
Most of this code is not templated methods. Rather, it implements over
several types to call templated functions, which creates quite a bit of
code. Rather than have all code using a reader recompile the code, just
compile it once and put it in a library.
