Re: [TTML2] tts:{width,height} rename

> tts:{ipd,bpd} are used to specify constraints on the dimensions of areas generated by content elements

This is in addition to region height/width, or instead, or something else?

Is there a ticket related to this feature?

Best,

-- Pierre

On Tue, Jan 27, 2015 at 8:12 AM, Glenn Adams <glenn@skynav.com> wrote:
> ipd = inline progression dimension
> bpd = block progression dimension
>
> they are the writing mode relative counterparts to width and height; the
> problem with the latter is that they are strongly associated with absolute
> axes (horizontal and vertical), while the former {ipd,bpd} don't suffer from
> that association
>
> it also requires less spec text and results in less confusion in the spec,
> since in all places at present (except for line height), width and height
> are interpreted in an absolute sense independent of writing mode
>
> tts:{ipd,bpd} are used to specify constraints on the dimensions of areas
> generated by content elements
>
> On Tue, Jan 27, 2015 at 7:37 AM, David Singer <singer@apple.com> wrote:
>>
>> yikes
>>
>> it’s nice if the terms are readable.  Linewidth and Lineheight have some …
>> recognition, albeit mostly in writing systems that use horizontal lines
>> assembled into vertical blocks.
>>
>> ipd and bpd are directions, not measurements, aren’t they? and they don’t
>> exactly roll off the tongue or leap to mind in terms of recognizability
>>
>> > On Jan 26, 2015, at 1:01 , Glenn Adams <glenn@skynav.com> wrote:
>> >
>> > The use of width and height as writing mode relative properties is
>> > confusing. Change their names to ipd and bpd, abbreviations for inline
>> > progression dimension and block progression dimension, respectively, and
>> > document convention that width and height (as well as horizontal and
>> > vertical) are always absolute and not writing mode relative. The only
>> > exception being that 'height' in lineHeight remains writing mode relative,
>> > i.e., specifies the nominal bpd of a line area.
>> >
>> > Change image to use tts:extent instead of the former tts:{width,height}
>> > in order to use absolute axes in expressing explicit image dimensions.
>> >
>> > Addressed above comments in [1].
>> >
>> > [1] https://dvcs.w3.org/hg/ttml/rev/69877acd9380
>>
>> David Singer
>> Manager, Software Standards, Apple Inc.
>>
>>
>

Received on Tuesday, 27 January 2015 16:39:42 UTC