How can I tell if a feature is enabled by default? Is it constant across scripts? And are feature values always True/False
On Fri, Jul 1, 2016 at 6:34 PM, Ebrahim Byagowi <[email protected]> wrote: > By passing a list of opentype features to harfbuzz, it just modifies the > default status of them but still has knows which ones should be enabled or > disabled in case user didn't explicitly set them. > > > Because i can turn off LIGA by passing a LIGA feature with value=0 and > nothing will happen to arabic but CALT with value=1 changes it > In case of LIGA and CALT difference, that depends on that specific font > you are using whether it has marked which feature by which tag. An > identical stylic operation can have two different tag on different fonts. > > On Sat, Jul 2, 2016 at 2:58 AM, Kelvin Ma <[email protected]> > wrote: > >> Now I’m even more confused, will harfbuzz override the features in the >> features array if it’s setting arabic? Because i can turn off LIGA by >> passing a LIGA feature with value=0 and nothing will happen to arabic but >> CALT with value=1 changes it >> >> On Fri, Jul 1, 2016 at 6:24 PM, Ebrahim Byagowi <[email protected]> >> wrote: >> >>> Different and essential operations of a shaper are divided and marked by >>> features and some features are enabled by default per the specification, >>> for example on Arabic >>> https://www.microsoft.com/typography/OpenTypeDev/arabic/intro.htm#features >>> >>> On Sat, Jul 2, 2016 at 2:33 AM, Kelvin Ma <[email protected]> >>> wrote: >>> >>>> && why does harfbuzz still use features if I pass it an empty list? How >>>> does it know whether to turn them on or off? >>>> >>>> On Fri, Jul 1, 2016 at 6:02 PM, Kelvin Ma <[email protected]> >>>> wrote: >>>> >>>>> So that’s what the value member does. thanks! Will it always be either >>>>> 0 or 1? >>>>> && what does .tag do? >>>>> >>>>> On Fri, Jul 1, 2016 at 5:51 PM, Simon Cozens <[email protected]> >>>>> wrote: >>>>> >>>>>> On 02/07/2016 07:34, Kelvin Ma wrote: >>>>>> > So I think I figured out how to turn on font features, but how do I >>>>>> turn >>>>>> > ones off that are enabled by default? Like liga or kern? >>>>>> >>>>>> Just set the value to 0 in the features array. >>>>>> See >>>>>> >>>>>> https://github.com/simoncozens/sile/blob/master/src/justenoughharfbuzz.c#L78 >>>>>> >>>>>> Simon >>>>>> >>>>>> >>>>> >>>> >>>> _______________________________________________ >>>> HarfBuzz mailing list >>>> [email protected] >>>> https://lists.freedesktop.org/mailman/listinfo/harfbuzz >>>> >>>> >>> >> >
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