Re: tts:rubyReserve + tts:lineHeight (issue #779)

ok, but it may take me a day or two to prepare the details given my current
task queue

On Mon, May 21, 2018 at 5:55 PM, Pierre-Anthony Lemieux <pal@sandflow.com>
wrote:

> Can you provide a concrete example?
>
> On Mon, May 21, 2018 at 4:53 PM Glenn Adams <glenn@skynav.com> wrote:
>
>> No. The way I wrote the suggested refinement covers both the cases where
>> the author specifies ruby font size and cases where the default ruby font
>> size algorithm supplies that answer.
>>
>> On Mon, May 21, 2018 at 5:46 PM, Pierre-Anthony Lemieux <pal@sandflow.com
>> > wrote:
>>
>>> > and the maximum  used bpd of the any inline area generated by a ruby
>>> text container for that paragraph.
>>>
>>> The author would need to specify the ruby text font size that would
>>> generate the ruby text container for that paragraph, since the ruby
>>> text font size is not always 50% of the ruby container font size.
>>>
>>> On Mon, May 21, 2018 at 4:12 PM Glenn Adams <glenn@skynav.com> wrote:
>>>
>>>> Perhaps we could accommodate your concern by a slight change to the
>>>> current default length computation: we could make it the maximum of the
>>>> currently specified computation and the maximum  used bpd of the any inline
>>>> area generated by a ruby text container for that paragraph.
>>>>
>>>> On Mon, May 21, 2018 at 3:22 PM, Pierre-Anthony Lemieux <
>>>> pal@sandflow.com> wrote:
>>>>
>>>>> > How is this different from assigning a length value for lineHeight
>>>>>
>>>>> An author does not need to account for the presence of ruby text when
>>>>> specifying tts:lineHeight. Instead, as I understand the specifications, the
>>>>> processor automatically grows the line area height if the computed value of
>>>>> tts:lineHeight is not sufficient to accommodate the ruby text (of the font
>>>>> size specified by the author) -- see attached examples.
>>>>>
>>>>> Why should the author have to set the line height manually when using
>>>>> tts:rubyReserve?
>>>>>
>>>>> Best,
>>>>>
>>>>> -- Pierre
>>>>>
>>>>> [image: 0.png]
>>>>>
>>>>> On Mon, May 21, 2018 at 1:00 PM Glenn Adams <glenn@skynav.com> wrote:
>>>>>
>>>>>> How is this different from assigning a length value for lineHeight in
>>>>>> a non-ruby paragraph and not knowing whether the fonts used will fit the
>>>>>> line? I think you could say exactly the same thing there:
>>>>>>
>>>>>> >It is therefore impossible for the author to accurately specify a
>>>>>> <length>, and the default value might not be appropriate.
>>>>>>
>>>>>> On Mon, May 21, 2018 at 11:59 AM, Pierre-Anthony Lemieux <
>>>>>> pal@sandflow.com> wrote:
>>>>>>
>>>>>>> Hi Cyril, Glenn et al.,
>>>>>>>
>>>>>>> The following is based on my working on implementing tts:rubyReserve
>>>>>>> in imscJS.
>>>>>>>
>>>>>>> tts:rubyReserve is intended to reserve room to contain inline areas
>>>>>>> generated by ruby annotations and emphasis marks, regardless of whether the
>>>>>>> latter are present at a given instant in time.
>>>>>>>
>>>>>>> As currently specified, the amount of room reserved is explicitly
>>>>>>> specified by the author as a <length>, or, if left unspecified, set to a
>>>>>>> default value equal to 50% of the used value of the tts:lineHeight
>>>>>>> applicable to the p element.
>>>>>>>
>>>>>>> I see a fundamental challenges with this approach:
>>>>>>>
>>>>>>> (a) neither tts:ruby nor tts:textEmphasis specify the amount of room
>>>>>>> needed for ruby annotations and emphasis marks, respectively -- the amount
>>>>>>> of room is left to the implementation. It is therefore impossible for the
>>>>>>> author to accurately specify a <length>, and the default value might not be
>>>>>>> appropriate.
>>>>>>>
>>>>>>> (b) the default value is not sufficient if the author specifies a
>>>>>>> font size for ruby annotations that is different from the ruby base font
>>>>>>> size.
>>>>>>>
>>>>>>> I suggest exploring the following tweak to the semantics of
>>>>>>> tts:rubyReserve:
>>>>>>>
>>>>>>> """
>>>>>>> The implementation reserves room for ruby annotations and emphasis
>>>>>>> marks assuming:
>>>>>>> - the font size of the base text is the same as that of the <p>
>>>>>>> - the font size of the annotation/emphasis mark is specified by the
>>>>>>> <length> or, if the <length> is not specified, computed according
>>>>>>> to 10.2.21.1
>>>>>>> """
>>>>>>>
>>>>>>> I will be on the road and unavailable for the next two TTWG calls. I
>>>>>>> am however available today and tomorrow to discuss live​, and will be
>>>>>>> available over email.
>>>>>>>
>>>>>>> Best,
>>>>>>>
>>>>>>> -- Pierre
>>>>>>>
>>>>>>
>>>>>>
>>>>
>>