Created attachment 129971 [details]
Screenshot from Firefox

Firefox set an good example for how upright characters performanced within vertical layout. To reproduce this, I copied all the characters from attachment 128899 [details].

Mark Hung, WDYT?

Confirm that characters of Tangut script are shifted to the left in vertical layout when OpenGL enabled. u+18801 might be the most obvious one. Note my video card is blacklisted, so I have checked "Ignore OpenGL blacklist".


Version：5.3.0.1 (x64)
Build ID：3b800451b1d0c48045de03b5b3c7bbbac87f20d9
CPU Thread：8; OS Version：Windows 6.19; UI Render：GL; Layout Engine: new;
Locale: zh-TW (zh_TW); Calc: single

I can’t download the font (404 error) but the screenshot on the website shows only horizontal text, are you sure the fonts supports vertical layout (has vertical glyph metrics and so on)?

(In reply to Khaled Hosny from comment #4)
> I can’t download the font (404 error) but the screenshot on the website
> shows only horizontal text, are you sure the fonts supports vertical layout
> (has vertical glyph metrics and so on)?

You can try to get the font from attachment 130486 [details]. If you have problem for this font, you can contact the author from here: http://ccamc.co/introduction.php

(In reply to Volga from comment #5)
> (In reply to Khaled Hosny from comment #4)
> > I can’t download the font (404 error) but the screenshot on the website
> > shows only horizontal text, are you sure the fonts supports vertical layout
> > (has vertical glyph metrics and so on)?
> 
> You can try to get the font from attachment 130486 [details]. If you have
> problem for this font, you can contact the author from here:
> http://ccamc.co/introduction.php

The font lacks vertical metrics tables (vmtx, vhea) or any OpenType features, so it is not unreasonable for the font not to work well with vertical text.

AFAIC, this is not a bug, but any one is free to come up with a reasonable patch to fix this.

(In reply to Khaled Hosny from comment #6)
> (In reply to Volga from comment #5)
> > (In reply to Khaled Hosny from comment #4)
> > > I can’t download the font (404 error) but the screenshot on the website
> > > shows only horizontal text, are you sure the fonts supports vertical layout
> > > (has vertical glyph metrics and so on)?
> > 
> > You can try to get the font from attachment 130486 [details]. If you have
> > problem for this font, you can contact the author from here:
> > http://ccamc.co/introduction.php
> 
> The font lacks vertical metrics tables (vmtx, vhea) or any OpenType
> features, so it is not unreasonable for the font not to work well with
> vertical text.
> 
> AFAIC, this is not a bug, but any one is free to come up with a reasonable
> patch to fix this.

I understand, but why does Firefox work well at this point? (comment 1)

(In reply to Volga from comment #7)
> I understand, but why does Firefox work well at this point? (comment 1)

No idea, want to find out? May be they are doing something more clever than us.

(In reply to Khaled Hosny from comment #8)
> (In reply to Volga from comment #7)
> > I understand, but why does Firefox work well at this point? (comment 1)
> 
> No idea, want to find out? May be they are doing something more clever than
> us.

Let’s find it out. First, you open CodePen in Firefox, and click New Pen button, then copy the following codes into there:

<div style="font-family: Tangut N4694; font-size: 2em">
<p>𗀀𗀂𗀇𗀈𗀊𗀌𗀍𗀐𗀔𗀘𗀙𗀚𗀛𗀝𗀞𗀟𗀠𗀡𗀥𗀫𗀯𗀸𗀹𗀻𗀽𗀾𗀿𗁀𗁂𗁃𗁅𗁆𗁉𗁊𗁋𗁍𗁏𗁑𗁕𗁜𗁝𗁟𗁡𗁢𗁣𗁤𗁦𗁧𗁫𗁬𗁭𗁮𗁴𗁶𗁷𗁺𗁽𗁿</p>
<p>𘠀𘠁𘠃𘠈𘠊𘠋𘠐𘠒𘠔𘠕𘠙𘠚𘠛𘠞𘠠𘠡𘠣𘠤𘠧𘠨𘠪𘠫𘠬𘠭𘠮𘠲𘠳𘠵𘠶𘠼𘡀𘡂𘡃𘡄𘡅𘡈𘡉𘡊𘡋𘡍𘡎𘡒𘡓𘡔𘡖𘡗𘡘𘡚𘡛𘡜𘡡𘡢𘡣𘡤𘡦𘡩𘡪𘡫𘡮𘡯𘡰𘡱𘡵𘡷𘡸𘡽</p>
<p>𖿠</p>
</div>
<div style="font-family: Tangut N4694; font-size: 2em; writing-mode: vertical-rl; text-orientation: upright">
<p>𗀀𗀂𗀇𗀈𗀊𗀌𗀍𗀐𗀔𗀘𗀙𗀚𗀛𗀝𗀞𗀟𗀠𗀡𗀥𗀫𗀯𗀸𗀹𗀻𗀽𗀾𗀿𗁀𗁂𗁃𗁅𗁆𗁉𗁊𗁋𗁍𗁏𗁑𗁕𗁜𗁝𗁟𗁡𗁢𗁣𗁤𗁦𗁧𗁫𗁬𗁭𗁮𗁴𗁶𗁷𗁺𗁽𗁿</p>
<p>𘠀𘠁𘠃𘠈𘠊𘠋𘠐𘠒𘠔𘠕𘠙𘠚𘠛𘠞𘠠𘠡𘠣𘠤𘠧𘠨𘠪𘠫𘠬𘠭𘠮𘠲𘠳𘠵𘠶𘠼𘡀𘡂𘡃𘡄𘡅𘡈𘡉𘡊𘡋𘡍𘡎𘡒𘡓𘡔𘡖𘡗𘡘𘡚𘡛𘡜𘡡𘡢𘡣𘡤𘡦𘡩𘡪𘡫𘡮𘡯𘡰𘡱𘡵𘡷𘡸𘡽</p>
<p>𖿠</p>
</div>

Then you will see so many glyphs looks proportional in horizontal writing, but they looks centered within em-box when they displaying in vertical writing. That is what they should looks like. I think LibreOffice ꜱʜᴏᴜʟᴅ follow this practice.

You can also try Tangut Yinchuan[1] font on Firefox, just replacing font family property.

Ref:
[1] http://www.babelstone.co.uk/Fonts/Yinchuan.html

Here is an example for how does such glyphs should looks like when they are upright in vertical writing, I think this is suitable for Tangut N4694.

https://drafts.csswg.org/css-writing-modes-3/#valdef-text-orientation-upright

In CSS Writing Modes Level 3 section 6.3 there is an example of how upright glyph should be aligned within vertical text, you can see it in a green box, which is indicate as “Vertical baseline of an upright glyph”.

https://drafts.csswg.org/css-writing-modes-3/#line-orientation

Created attachment 130652 [details]
Test font

Created attachment 130653 [details]
Test font

Created attachment 130654 [details]
Test file

I have found another situation when I try to use attachment 130653 [details] in Writer, in this case Latin characters looks upright and they shifted to the left.

Created attachment 130655 [details]
Screenshot

Screenshot for attachment 130654 [details].

What happened if you intergrate HarfBuzz 1.3.4? This version has some improves for vertical layout.

(In reply to Khaled Hosny from comment #8)
> No idea, want to find out? May be they are doing something more clever than
> us.
Now I think bug 105650 has more detailed information for this, so close this bug.

*** This bug has been marked as a duplicate of bug 105650 ***