This patch adds an inheritable option, “font-shaping”, that controls
whether a particle that renders text should enable font-shaping or
not.
The option works similar to the ‘font’ option: one can set it at the
top-level, and it gets inherited down through all modules and to their
particles.
Or, you can set it on a module and it gets inherited to all its
particles, but not to other modules’ particles.
Finally, you can set it on individual particles, in which case it only
applies to them (or “child” particles).
When font-shaping is enabled (the default), the string particle shapes
full text runs using the fcft_rasterize_text_run_utf32() API. In fcft,
this results in HarfBuzz being used to shape the string.
When disabled, the string particle instead uses the simpler
fcft_rasterize_char_utf32() API, which rasterizes individual
characters.
This gives user greater control over the font rendering. One example
is bitmap fonts, which HarfBuzz often doesn’t get right.
Closes#159
All decoration, particle and module interfaces now takes a
pixman_image_t parameter, and all drawing is done using pixman APIs.
The wayland/xcb backends implement a new interface functions,
get_pixman_image(), that should return a pixman image instance that is
suitable for rendering.
In the wayland backend, the image uses the same backing data as the
cairo surface.
In the XCB backend, we create a new image each time, and then blit it
to the cairo surface at commit time.
