Created attachment 132986 [details]
Picture shows the font problem

The font is really broken. It provides a symbol “cmap” subtable that does not have a mapping for space character. Since the font does not support the space character as far as we are concerned we use a fallback font for it, and it will most likely have a different width.

I don’t know how other office applications are handling this, one possible explanation is that they are not doing any font fallback for fonts with symbol “cmap” subtable, which in turn will cause them to use the glyph for unsupported characters (glyph 0) which happens to be a white (empty) square in this font. This also why this font works in Scribus since it does not do any fallback for missing characters. I tried AbiWord but it gave me similar rendering as LibreOffice.

(In reply to Khaled Hosny from comment #2)
> The font is really broken. It provides a symbol “cmap” subtable that does
> not have a mapping for space character. Since the font does not support the
> space character as far as we are concerned we use a fallback font for it,
> and it will most likely have a different width.
> 
> I don’t know how other office applications are handling this, one possible
> explanation is that they are not doing any font fallback for fonts with
> symbol “cmap” subtable, which in turn will cause them to use the glyph for
> unsupported characters (glyph 0) which happens to be a white (empty) square
> in this font. This also why this font works in Scribus since it does not do
> any fallback for missing characters. I tried AbiWord but it gave me similar
> rendering as LibreOffice.

I tested the font "Chess Alpha" with the Software AbiWord 2.9.4, no problems there.

(In reply to Ekkehard May from comment #3)
> I tested the font "Chess Alpha" with the Software AbiWord 2.9.4, no problems
> there.

I tested with AbiWord 3.0.2 on Linux.

Created attachment 132994 [details]
Screenshot of AbiWord showing the same issue

Created attachment 132996 [details]
Screenshot AbiWord 2.9.4 for Windowsm correct rendering

(In reply to Ekkehard May from comment #6)
> Created attachment 132996 [details]
> Screenshot AbiWord 2.9.4 for Windowsm correct rendering

I assume AbiWord on Windows is using Uniscribe somehow, so it would be getting the same rendering as other Windows applications. It would be interesting to test Firefox/Chrome/InDesign etc. since these have their own layout engines.

I tested with InDesign 7.5 and there are no rendering problems.

Now i checked the "Space" glyph in the font "Chess Alpha" with FontCreator.

In the "Properties", Register "Mappings" i found this:
Platforms: "Microsoft Symbol"
Encoding format: "Segment mapping to delta values"
And in the mapping table there is a long list of mappings for the glyph:

Value     Characte Name
$F020     <$F020>
$F02A     <$F02A>
...etc.

Another Chess font, "Chess Berlin" [from the same author] is rendered correctly by LibreOffice and by OpenOffice
I checked this font with FontCreator, and the only difference i found is, that in the mapping table for the glyph "Space" there is only ONE mapping:

Value     Characte Name
$F020     <$F020>

Now i deleted all mappings in font "Chess Alpha", except the first mapping, and saved the font under a new name.
After i deletes the original font and replaced it with the modified one, OpenOffice rendered the white square correctly, but LibreOffice did not.

I'm confused.

Created attachment 133005 [details]
Screenshot Indesign 7.5 correct rendering

I’m trying to revisit this issue, but I can not reproduce anymore, can anyone else reproduce?