[HarfBuzz] Can I only reshape broken clusters?

[Behdad Esfahbod]

They are all heuristics.  Not sure which one is more accurate.

On Thu, Jun 30, 2016 at 9:15 PM,  <kelvinsthirteen at gmail.com> wrote:
> isn't that less accurate than what i’m doing here? since at least we are accounting for changes in ligature width or kerning
>
>> On Jul 1, 2016, at 12:10 AM, Behdad Esfahbod <behdad at behdad.org> wrote:
>>
>>> On Thu, Jun 30, 2016 at 9:06 PM,  <kelvinsthirteen at gmail.com> wrote:
>>>
>>>
>>>> On Jun 30, 2016, at 11:41 PM, Behdad Esfahbod <behdad at behdad.org> wrote:
>>>>
>>>> No, it wouldn't be safe necessarily.  That's exactly what the
>>>> unsafe-to-break API is about, but that's not finished yet.  For now,
>>>> you have to reshape the entire new string.
>>>
>>> That’s O(n^2) in terms of the amount of shaping that has to be done per paragraph based on the length of the paragraph text, and not workable in practice
>>
>> What Pango (and possibly other systems) does is to shape the full
>> paragraph, then find line-break location, then reshape the
>> just-decided line but continue with the rest of the paragraph as if
>> the shaping wouldn't change the width much.
>>
>>>>> On Thu, Jun 30, 2016 at 8:31 PM, Kelvin Ma <kelvinsthirteen at gmail.com> wrote:
>>>>> If I have the string A = 'affifibcd' and the master list of shaped glyphs
>>>>>
>>>>> [a 0] [ffi 1] [fi 4] [b 6] [c 7] [d 8]
>>>>>
>>>>> and I wanted to shape the substring A[2:] ('fifibcd'), could I simply take
>>>>> my preshaped glyphs after the cluster at or above (ceiling) i = 2 and only
>>>>> reshape the segment A[2:6]?
>>>>>
>>>>> So I would reuse the glyphs
>>>>>
>>>>> [fi 4] [b 6] [c 7] [d 8]
>>>>>
>>>>> and reshape the segment A[2:6] = 'fifi' to get
>>>>>
>>>>> [fi 2] [fi 4]
>>>>>
>>>>> and add them together (dropping the last glyph in the reshaped segment) to
>>>>> get
>>>>>
>>>>> [fi 2]  [fi 4] [b 6] [c 7] [d 8]
>>>>>
>>>>> ?
>>>>> Would this be the same result as reshaping the entire segment A[2:]? Would
>>>>> this still work for RTL text, or a substring that’s on the left-hand side of
>>>>> the parent string like A[:5] = 'affif'?
>>>>>
>>>>> _______________________________________________
>>>>> HarfBuzz mailing list
>>>>> HarfBuzz at lists.freedesktop.org
>>>>> https://lists.freedesktop.org/mailman/listinfo/harfbuzz
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> behdad
>>>> http://behdad.org/
>>
>>
>>
>> --
>> behdad
>> http://behdad.org/



-- 
behdad
http://behdad.org/