The --histogram output is now comma (rather than space) separated.

Initial correct treatment of pixel-aligned inputs, GFS files will be read as pixel-aligned, GMT netCDF files are read as per their node_offset attribute, Matlab MAT files as per their pixel variable and the new --pixel option specifies pixel-aligned CSV input.

The handling of pixel-aligned input is to use a node-aligned grid which is a half-pixel smaller than the boundary on each side, this might lead to plot failures when using very coarse input grids or very small arrows.

The boundary is now drawn only in the interior of the domain, so the value of --domain-pen option no longer affects the bounding-box of the plot. This should make composition a little simpler.

The --fill and --ellipse-fill options now accept named colours as commonly used in web-browsers, "red", "beige" and so-on.

All options which take a pen as argument (--pen and so-on) can now specify a colour in place of a greyscale value, including the named colours mentioned above.

All code updated to C99.

Redesign of how the boundary is handled. The "dimension climbing" approach of version 1 is replaced by considering the line-segments of the boundary as "semi-degenerate ellipses", the Perram-Wertheim distance can be generalised to this case. A report on these matters will be submitted for publication in due course.

The end result is that more-complex boundaries can be handled by the program.

The calculation of neighbours is now performed using R-trees rather than kd-trees. These are better suited to the (typically vertical and horizontal) line-segments of the boundary, and as a side-benefit results in a substantial performance boost.

Implemented autoscaling. In adaptive mode, if the --scale option is not specified, then vfplot will attempt to calculate the scaling required to give the number of arrows specified by the new --number option, or a sensible default (200).

The graphic-state files (see --graphic-state) are now in the JSON format.

The domain files (see --domain) are now in the GeoJSON format.

The simple ASCII grid input format, "sag", is retired, replaced by a CSV format. The program gfs-csv writes this format (given a Gerris simulation file) and the new csv-grd program will convert such files to GMT netCDF files for faster loading.

The format specifies the location in the grid by (offset-zero) grid indices in the first two columns, to allow these to be mapped to anywhere in plot-space, see the --grid-range and --grid-size options for vfplot and csv-grd

Acceptance-testing now uses the Bash Automated Testing System (BATS).

Added visual tests generating plots of the test fields if the --enable-visual-tests option is passed to configure.

Added memory tests (using valgrind) if the --enable-memory-tests option is passed to configure.

The bottom-level documentation files are now in markdown (generated by Pandoc) rather than the plain-text generated by the Lynx browser.

Acceptance tests which exercise the Gerris functionality are now skipped if the --enable-gerris configure option is not given.

POSIX threads on OS X. Compiling on OS X with the --pthread-extra option should create a multithreaded version of the program.

Fix floating point errors reading Gerris GFS files when compiled with gcc-8.

Fixed 50 defects found by Coverity static analysis.

Fixed a bug in the numerical calculation of the field radius of curvature used in the dynamic.

The sag2grd utility rewritten in Python, works with GMT versions 4 or 5.

Short-circuit when the Perram-Werthiem distance is found to be greater than one (the ellipses do not intersect) giving a 20% speedup.

Updated to the latest version of John Tsiombikas's kdtree library.

Simplification of the threading code.

Rewrote the POSIX threading for the force calculation, resulting in a substantial speedup on multiprocessor hardware: A plot taking 10 seconds with -j1 will now typically take 6.5 seconds with -j2 on a dual-processor machine.

The default behaviour is now to use as many threads as there are CPUs on the system, if this number can be determined. Otherwise one thread is used.

Updated the gfs2xyz2D program to compile against the most recent version of Gerris following the removal of some obsolete API features in January 2012.

Fixed a domain generation bug (strange winding number)

Modified the sag2grid program to handle input files with leading and trailing whitespace

Fixed Makefile for sag2grid so that it is now actually installed.

Simplified the bilinear grid code and modified the radius of curvature calculation therein to use one-sided derivatives if the two-sided devivatives cannot be used due to lack of data.

The result is that curvature data is usually available right up to edge of the boundary, improving robustness.

The triangle glyph is now the default glyph.

Fix for incorrect order of output grd files in sag2grd

Fixed a buffer overrun

Minor bugfixes found during the Windows/Cygwin port.

Output to POV-Ray with --output-format povray.

Added a --graphic-state option to cache the results of long program runs for final adjustment of line widths, fill colour, glyph type and so on.

Reading of Matlab binary files.

Added a --ke-drop option which delays termination until the kinetic energy has dropped by the specified dB.

Simplified the potential used in the dynamic — removal of the attractive tail allows us to reduce the number of neighbours and so speed up the dynamic by around a factor of two.

Added a perl script sag2grd which converts a sag(5) file to grd files.

Added a --sag option to the gfs2xyz2D program causing it to write a sag(5) header to the output data.

Fixed floating point exception bug in dim2.c

Fixed a fencepost error in dim2.c which caused a leak in the boundary during the dynamic.

The default value for the --threads option is now 1 rather than the number of CPUs. Use a value of 0 to restore the autodetection.

Removed thread creation/destruction and attendant overhead when the processing is single-threaded.

Removed signal handler for SIGFPE since, according to POSIX, ignoring it results in undefined behaviour.

Several fixes in the autoconf handling of sincos(), alloca() etc for the FreeBSD port.

Added a --glyph option for alternative glyphs. New wedge and triangle glyphs.

Added a --aspect option to adjust the aspect (the ratio of length to width) of the glyph.

Corrected sag(5) documentation

Reduced the verbosity of some warnings

Read and write support for the sag(5) format

Implemented autodetection of input files formats (using file magic)

Added -L option for late decimation and --decimate-contact for finer control the decimation