investigate whether using a single instance of ghostscript for ps->png conversion can speed up the Windows build

[anntzer]

Keeping a single instance of Inkscape for the svg->png conversion greatly speeds up the Windows build (#8248 (comment)).

It appears that ghostscript may similarly be opened and convert files fed on stdin one at a time. Quoting relevant portions of the man page:

gs reads "files" in sequence and executes them as Ghostscript programs. After doing this, it reads further input from the standard input stream (normally the keyboard), interpreting each line separately. The interpreter exits gracefully when it encounters the "quit" command (either in a file or from the keyboard), at end-of-file, or at an interrupt signal (such as Control-C at the keyboard).

You might want to print each page separately. To do this, send the output to a series of files "foo1.xyz, foo2.xyz, ..." using the "-sOutputFile=" switch with "%d" in a filename template:
-sOutputFile=foo%d.xyz
Each resulting file receives one page of output, and the files are numbered in sequence. "%d" is a printf format specification; you can also use a variant like "%02d".

You can also send output to standard output:
-sOutputFile=-
or
-sOutputFile=%stdout%
In this case you must also use the -q switch, to prevent Ghostscript from writing messages to standard output.

I have no idea how much (if anything) would be gained but given the results with Inkscape it may be worth looking at it to speed up the Windows build...

[anntzer]

Closed by #9454.