i still don’t get it how does cairo know about the device table in the harfbuzz font object if cairo uses a different font object to do its rendering?
> On Jun 28, 2016, at 8:28 PM, Khaled Hosny <[email protected]> wrote: > > Device tables affect glyph positioning which is done by HarfBuzz to > Cairo. > >> On Tue, Jun 28, 2016 at 07:50:51PM -0400, Kelvin Ma wrote: >> The rendering is separate from harfbuzz i thought, the glyphs get passed to >> cairo’s cr.show_glyphs() and it uses its own font structure that has to be >> loaded separately from harfbuzz’s fonts. So any value set on the harfbuzz >> font is not known by the renderer >> >>> On Tue, Jun 28, 2016 at 7:48 PM, Khaled Hosny <[email protected]> wrote: >>> >>> For device tables (as I said in my first reply) and I think hinting >>> (though I don’t think hinting stuff affects HarfBuzz right now). >>> >>>> On Tue, Jun 28, 2016 at 07:25:27PM -0400, Kelvin Ma wrote: >>>> ok this might be a dumb question but what is ppem used for anyway? I >>>> thought it was a font value that harfbuzz just lets you read off of the >>>> font (like upem, advance width, or glyph index) so you can do your own >>> math >>>> on the font outside of harfbuzz. >>>> >>>> On Tue, Jun 28, 2016 at 7:18 PM, Khaled Hosny <[email protected]> >>> wrote: >>>> >>>>> It is, but you have to set it separately, and then you can set the font >>>>> scale to whatever value you need without both being interdependent. >>>>> >>>>>> On Tue, Jun 28, 2016 at 07:15:23PM -0400, Kelvin Ma wrote: >>>>>> I thought ppem was dependent on UPEM and font scale, is it not? >>>>>> >>>>>> On Tue, Jun 28, 2016 at 7:12 PM, Khaled Hosny <[email protected] >>>> >>>>> wrote: >>>>>> >>>>>>> Device tables depend on ppem, so despite the scale being set >>>>>>> on the font, you should still set the exact ppem. >>>>>>> >>>>>>> On Tue, Jun 28, 2016 at 06:43:58PM -0400, Kelvin Ma wrote: >>>>>>>> so that’s the only way huh… >>>>>>>> doesn’t that kind of defeat the purpose of hb.font_create() and >>>>> having >>>>>>> many >>>>>>>> scaled versions of the same font? You would only ever need one >>> font >>>>> of >>>>>>> each >>>>>>>> face, scaled to the UPEM, if the fontsize was to be applied >>>>> externally >>>>>>>> after shaping already occurred. >>>>>>>> >>>>>>>> On Tue, Jun 28, 2016 at 5:51 PM, Behdad Esfahbod < >>> [email protected]> >>>>>>> wrote: >>>>>>>> >>>>>>>>> HarfBuzz coordinates work in a int32 space. You are free to >>> set >>>>>>> whatever >>>>>>>>> scales you want on the font. For example, use 6 or 8 or 10 or >>> 16 >>>>> bits >>>>>>> of >>>>>>>>> sub-pixel precision by multiplying your scale by a number. >>>>>>>>> >>>>>>>>> On Tue, Jun 28, 2016 at 4:57 PM, Kelvin Ma < >>>>> [email protected]> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> It appears that harfbuzz rounds all decimals to integers when >>>>> giving >>>>>>>>>> glyph advances and offsets. This is causing some ugly >>> misalignment >>>>>>> problems >>>>>>>>>> in arabic shaping, as well as latin cursive fonts. (see >>> pictures) >>>>>>>>>> >>>>>>>>>> [image: Inline image 1] >>>>>>>>>> >>>>>>>>>> [image: Inline image 2] >>>>>>>>>> >>>>>>>>>> [image: Inline image 3] >>>>>>>>>> How do I get harfbuzz to preserve the floats? >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> HarfBuzz mailing list >>>>>>>>>> [email protected] >>>>>>>>>> https://lists.freedesktop.org/mailman/listinfo/harfbuzz >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> behdad >>>>>>>>> http://behdad.org/ >>>>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> HarfBuzz mailing list >>>>>>>> [email protected] >>>>>>>> https://lists.freedesktop.org/mailman/listinfo/harfbuzz >>>>>>> >>>>>>> >>>>> >>> _______________________________________________ HarfBuzz mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/harfbuzz
