[Dev-luatex] Re: missing displacement when leqno is used in rtl paragraph

On 2/1/2025 11:44 AM, Udicoudco wrote:

On Fri, Jan 31, 2025 at 8:56 PM luigi scarso wrote:

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Luigi, after testing all the branches it seems there are a couple more that should be fixed. Sorry for not checking that before.

Ok, I will check it this weekend .

I've tested a little bit more, and unfortunately the situation is more complicated than I thought.

It seems the value of \pagedirection at shipout time affects the position (but not direction) of horizontal boxes. If \pagedirection is 0 at shipout time, hboxes are left aligned with the page box, If \pagedirection is 1 at shipout time, hboxes are right aligned with the page box.

This means if the equation box's (including the kern and equation number) width is less than the line width, the position of the equation will be dependent on the value of \pagedirection at shipout time.

Since we can't know what will be the value of \pagedirection at shipout time in finish_displayed_math, the only solution I can think of, is to make sure the equation box has the width of a line, by padding with white (a kern) space if needed. Is this an acceptable solution?

You can best try to handle this at the macro level. Page direction can badly interfere anyway and every change we make to the diretion code will introduce another issue. Just don't use it. FWIW, in luametatex we don't even have \pagedirection any more. With r2l typesetting one needs to keep a lot in mind, because nto all bozes one can come up with need to be reflected. Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl -----------------------------------------------------------------