Re: [css-text] Arabic letters connecting between elements with display: inline

On 5/22/2014 12:09 PM, Behdad Esfahbod wrote:
> On 14-05-22 03:28 AM, Matitiahu Allouche wrote:
>> Fantasai wrote: " I don't think change of font or color should cause a joining break, however."
>>
>> I agree that change of color should not mandate a joining break. On the other hand, a change of font, or a change of size in the same font, seems to make joining across the change very difficult technically. It would be quite extraordinary that letters from two fonts crafted by different designers join properly.
>> If the technical hurdle is such that there is little chance that implementations will overcome it, then it might be better to pronounce that there will be no joining across font or size changes.
> I disagree.  Joining should NOT be broken even if font changes.  Using a bold
> font to highlight a letter in print is a valid use.  It's hard.  But the
> alternative is wrong.  Whether user uses a different font weight or a
> different color to highlight shouldn't affect the correctness of the script
> behavior.
>
What software support joining (other than color) today?

These are the cases:
- disparate font family (different design)
- disparate weight (otherwise same design and size)
- disparate size (same design)

We found out already that some software can handle joining across color 
changes.

I can just about imagine that a designer can create a bold font so that 
it can work with the regular font, but that a rendering engine might 
have a hard time realizing that they belong together in all circumstances.

For different sizes, the rendering engine should be able to know that it 
deals with the same design, but depending on the design of the engine, I 
don't see that it's necessarily even possible to link up joining shapes, 
let alone make that look good.

For didactic purposes, what is wrong with inserting join controls? That 
would cause the correct shape to be selected (to within the limitations 
of that model) but might not be enough to position both sides correctly 
so that they actually join up; would depend on the fonts.

But it would allow high-end renderers to recognize the intent and do the 
right thing, if possible.

A./