Introduce a new icon particle. It follows the icon
spec (https://specifications.freedesktop.org/icon-theme-spec/latest/index.html).
Rendering logic is taken from fuzzel (using nanosvg + libpng), while loading
logic is taken from sway. Standard usage is with `use-tag = false` which expands
the provided string template and then loads the string as the icon name. There
are settings to manually override the base paths, themes, etc. The second usage
which is required for tray support is a special icon tag that transfers raw
pixmaps. With `use-tag = true` it first expands the string, and then uses that
output to find an icon pixmap tag. To reduce memory usage, themes are reference
counted so they can be passed down the configuration stack without having to
load them in multiple times.
For programmability, a fallback particle can be specified if no icon/tag is
found `fallback: ...`. And the new icon pixmap tag can be existence checked in
map conditions using `+{tag_name}`.
Future work to be done in follow up diffs:
1. Icon caching. Currently performs an icon lookup on each instantiation & a
render on each refresh.
2. Theme caching. Changing theme directories results in a new "theme collection"
being created resulting in the possibility of duplicated theme loading.
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
One can now bind the left/middle/right mouse buttons to on-click. In
fact, you can have all three buttons bound to different handlers for
the same particle. The new syntax is
on-click:
left: <command>
middle: <command>
right: <command>
Leaving one out is the same thing as not mapping it at
all. Furthermore,
on-click: <command>
is still valid, and is a shorthand for
on-click:
left: <commsnd>
