[ft-devel] Revisiting LSB [1]

[Ulrich]

George Williams writes: 

[...] 

> > 2. What test suites are available?
> There is a stress test generation program available from fontforge which
> will take a directory of normal fonts, mangle them, and make sure that
> the library doesn't crash on them.
> http://cvs.sourceforge.net/viewcvs.py/fontforge/fontforge/test/randomtest.c?rev=1.1&view=log
> (initially designed for fontforge, but modified to work for freetype
> too). 
>
> It is very difficult to come up with a general testsuite for font
> rasterization. There are many possible "good" solutions, the "best" will
> vary from display to display, individual esthetics are often different.
> -- It's not like a compiler where the result either succeeds or fails.

Sure, but as long as FreeType deterministically produces its results 
depending on certain parameter settings (including the automatically 
detected environment) testing is still a matter of deciding whether these 
results are still the same compared to previously generated results. 

And like testing other software there has to be a decision by the 
implementor of the test suite which will be the correct results to use in 
the comparisions. Testing FreeType's rasterisation would require a set of 
rasterisation results probably stored in files that have been proven to be 
correct by human inspection.