Pre-release testing version of gnuplot 6.0.4

[Ethan A M. <me...@uw...>]

I have placed a testing version of the source release
package for gnuplot 6.0.4 on the "testing" section of the
SourceForge download site.

    https://sourceforge.net/projects/gnuplot/files/gnuplot/testing/

Nothing major to look for in this release, but it does include a number
of recent bug fixes.　The configure script and various header files
have been modified to allow use with C compilers that enforce c23
syntax by default. This should not affect use with older compilers.

My tentative plan is to announce the actual release in about
two weeks (the week of 15 December).  That can be pushed back
if you find any problems or want to suggest inclusion
of a bug-fix from the development version that was not yet
backported.

Brief release notes below, or see 
     gnuplot.sourceforge.net/ReleaseNotes_6_0_4.html



%%%%%%%%%%    6.0.4 Release Notes 01-December-2025    %%%%%%%%%%%%%%%%

NEW (back-ported from development version)
------------------------------------------
* variable Inf is pre-set to floating point INFINITY
* "sharpen" filter handles vertical edges in a step function
* gprintf format specifiers %C and %Ci
  - %C  formats a complex value as {a, b}
      This is the format used by the gnuplot "print" command
  - %Ci formats a complex value as a + bi
      Both the real and imaginary parts are printed using libc format %g
      with optional width and precision
* Support for Windows on ARM 64-bit architectures
  - mingw: optionally use the MSYS2/CLANG64 environment
  - Cross-compilation for Windows on ARM is possible using MSYS2/CLANG64/CLANGARM64

CHANGES
-------
* better adherence to c23 standard
* splot with pm3d fillcolor <x> generates a matching key sample
* gprintf %H format is distinct from %h in utf8 context
  - %H uses dot operator between mantissa and exponent
* kitty, sixel: default size to 100% width, 75% height of terminal window
* Partially deprecate the "sample" keyword for plot commands.
  The plot command accepts axis ranges as the first thing after "plot".
  If present, they update the primary axis ranges x y x2 y2.
  However if this is preced by the keyword "sample" it refers to a sampling range
  rather than an axis range.  If a second colon is found in the range,
  as in [t=min:max:increment], this is unambiguously a sample range so the
  "sample" keyword is not required.
* Do not break contour lines into 100-segment fragments.
  - This fixes a bug when saved contour lines are used as polygons.
  - To maintain previous placement of contour labels along long contours, use
  "set cntrlabl interval 100".

FIXES
-----
* sixel: improved support for a transparent background
* kitty: support animation on a transparent background
* webp:  support animation on a transparent background
* backport fixes for color assignment to pm3d surfaces
  - "set pm3d implicit" + "with lines" treated the same as "with pm3d"
  - adds support for "fc background"
  - pm3d interpolate > 1 inherits rgb color assignments from the parent tile
* fill style of colorbox should match fill style of pm3d surface
* svg: fillstyle solid <frac> was incorrectly treated as transparent
* transparent fill color in 3D boxes and polygons
* alpha channel colors on ARM platforms
* resolve ambiguous syntax in "set dashtype i (n,m)"
* svg: font size changes within a text fragment could be lost
* "reset session" must terminate multiplot mode
* determination of above/below in polar mode filledcurves
* always flush cached lines from hidden3d if any are present
* incorrect evaluation of a**b for integer a, integer b < 0
  in the case that overflow handling has been set to "NaN" or "undefined"
* loss of precision in some ranges for asin acos asinh acosh


-- 
Ethan A Merritt
Department of Biochemistry
University of Washington, Seattle