Borderstyle=3 box height is affected by fallback fonts

[rahulshivajipawar]

Borderstyle=3 box height is affected by fallback fonts

[TheOneric]

Thanks for your report! Unfortunately though, it is not immedeatily obvious to me what issue you are referring to and you will need to be a bit more precise.
Checking against Google’s online rendering nothing stands out to me on first glance:

• Describe in detail what exactly appears wrong to you? What result were you expecting instead?
• Replace put-your-other-options-here to match your example (using the real video and subtitle file used to produce the screenshot) and then run ffmpeg -v debug put-your-other-options-here 2>&1 | tee -a 691.log and upload the resulting 691.log file. This is important to see which fonts get actually selected and gives more info about your libass version.
• Please provide the exact command line options you were using (you can redact file paths)
• If you have access to a MS Windows installation, have you checked if VSFilter produces the same result? (ideally xy-VSFilter and mention what version of Windows you were testing on)

[rahulshivajipawar]

The precise issue is that background is not wrapped correctly around "spaces" between words and at the "period".

[rcombs]

So this is specific to BorderStyle 3, then?

[astiob]

Based on the screenshots, looks like a case where the named font doesn't contain Kannada (but does contain spaces and full stops) and a substitute font with different metrics is selected.We render BorderStyle 3 for each glyph, but it should be rendered for each glyph run using the main font's metrics. In fact, the metrics of glyphwise substitute fonts should not affect *anything*, not only BorderStyle 3. For example, line height/spacing suffers as well.

[rahulshivajipawar]

So this is specific to BorderStyle 3, then?

Yes, this is specific to BorderStyle 3.

[rahulshivajipawar]

Based on the screenshots, looks like a case where the named font doesn't contain Kannada (but does contain spaces and full stops) and a substitute font with different metrics is selected.We render BorderStyle 3 for each glyph, but it should be rendered for each glyph run using the main font's metrics. In fact, the metrics of glyphwise substitute fonts should not affect anything, not only BorderStyle 3. For example, line height/spacing suffers as well.

You are correct. I tried changing the font type from "Noto Sans" to "Noto Sans Kannada" in ass file, then all the glyphs are rendered consistently. During the original rendering, "spaces" and "period" were probably rendered using "Noto Sans" font while the rest of the glyphs were rendered using the substitute font "Noto Sans Kannada."