Underline & Strikethrough handling not documented well

[spirali]

Underline and strikethrough does not draw any line.

I have tried enable it just by:

    builder.push_default(StyleProperty::Underline(true));

or setting all properties:

    builder.push_default(StyleProperty::Underline(true));
    builder.push_default(StyleProperty::UnderlineBrush(Some(text_color)));
    builder.push_default(StyleProperty::UnderlineSize(Some(5.0)));
    builder.push_default(StyleProperty::UnderlineOffset(Some(1.0)));

in both cases, the text is drawn but without the decoration. I have both tested main branch and version 0.2.0.

[DJMcNab]

Parley won't emulate underline drawing for you; you need to wire it up yourself using the offset provided by GlyphRun::style.

See for example the relevant code in Masonry: https://github.com/linebender/xilem/blob/771eb2f02f3d6629b78fe233fdec76a563ddbbb2/masonry/src/text/render_text.rs#L86-L119

Note that this code is for Parley 0.1.0, although I don't believe that this part has changed.

Our documentation of an expected integration isn't very thorough.

[spirali]

Thank you for your explanation!

[waywardmonkeys]

@spirali I think it is reasonable to keep this open and change it to indicate that we need to improve the documentation.

[spirali]

Ok. Btw: I think that it would be nice to put a simple implementation into examples swash_render and tiny_skia_renderer or at least to put there a comment that the user needs to implement this part manually.

[nicoburns]

Btw: I think that it would be nice to put a simple implementation into examples swash_render and tiny_skia_renderer or at least to put there a comment that the user needs to implement this part manually.

Totally agree. I made those examples, and the only reason that this code is not included as part of them is because I also missed the fact that it was necessary!