On 04/01/2002 07:24:40 PM Markus Scherer wrote:
>> I believe that the current mirrored and mirrored glyph properties are >> useful only when no help can be obtained from the font; otherwise, the >> resolved directionality should be provided to the font, which should >> then select the appropriate shape for each and every character, >> regardless of the mirrored and mirrored glyph properties. > > >Correct, and this is how the BidiMirroring.txt file is intended: Only if the >layout engine+font are not smart enough, as a fallback mechanism. This raises a question in my mind: how is an app to know whether the layout engine+font are smart enough? What if the app makes the wrong assumption about the rendering components, does a character transformation, and then the rendering components do a glyph transformation on the transformed characters? Consider an OpenType + Uniscribe implementation: Either Uniscribe can do a character transformation before doing cmap lookups and calling the OpenType engine, or Unscribe can set features (as Eric suggested), assuming the font supports those features (a reasonable assumption: OT fonts have to be created to a spec with regard to features that need to be used to support a given script). But (I gather) Uniscribe currently isn't doing either. So, an app might currently be doing something, but it doesn't have any way (that I know of) to ask a future version of Uniscribe whether it does handle mirroring through one mechanism or the other. In other words, it seems to me that it must be agreed that an app should assume it is handled by Uniscribe/OT, or should assume that it is not. - Peter --------------------------------------------------------------------------- Peter Constable Non-Roman Script Initiative, SIL International 7500 W. Camp Wisdom Rd., Dallas, TX 75236, USA Tel: +1 972 708 7485 E-mail: <[EMAIL PROTECTED]>
