Manual of Lua-OOCairo: fontopt
lua-oocairo-fontopt - options controlling text rendering
A font options object contains options that tell Cairo how to render
text on surfaces. They can be created with the
function in the main oocairo module (see lua-oocairo(3)), and
retrieved from scaled fonts or context objects with
Font options objects can be compared with the
== operator. Two different
objects with the same options set will be considered equal.
The following methods are available on font options objects:
- opt:copy ()
Returns a new font options object, with identical options to opt. The two objects will be completely independent, so you can set them to have different options.
- opt:get_antialias ()
Get the current antialiasing mode, which will be one of the strings accepted by the
- opt:get_hint_metrics ()
Returns the current hint metrics option, which will be one of the same strings accepted by the
- opt:get_hint_style ()
Get the kind of font hinting done when rendering text. Returns one of the strings accepted by the
- opt:get_subpixel_order ()
Returns the current ordering of colour components in pixels used for subpixel rendering, which will be one of the same strings accepted by the
- opt:hash ()
Return a number which can be used as a hash key identifying the particular options in opt. That is, if you wanted to cache fonts according to the options set on them, you could store them in a table with this hash value as the key. Two font options objects with the same options will have the same hash value.
- opt:merge (srcopt)
Add any options which are set to a non-default value in srcopt to opt if that still has the default value from them. The options in srcopt will be unchanged. Nothing is returned.
- opt:set_antialias (antialiastype)
Set the antialiasing mode used for drawing. The argument must be a string or boolean value accepted by the
set_antialiasmethod on context objects (see lua-oocairo-context(3)).
- opt:set_hint_metrics (hintmetrics)
Set the kind of hinting to be applied to the metrics, as opposed to outlines, of the glyphs in a font. The hintmetrics value must be one of the following strings:
- opt:set_hint_style (hintstyle)
Set the kind of font hinting done when rendering text. The hintstyle value must be one of the following strings:
- opt:set_subpixel_order (order)
Used to inform Cairo of the arrangement of colour components in the pixels of a display device like a monitor. Only applies if subpixel antialiasing is used. The order value must be one of the following strings:
The last two options refer to vertical arrangements of colours.