Stuck in parsing css in some svg.

[kkwpsv]

The stack when stuck is as below:

Here is two svgs which caused stuck.
svg.zip

[alo00]

I have the same problem with this file.
freeze.zip

It also freezes the UI if in a SvgViewBox like this :

    <Grid>
        <svgc:SvgViewbox Stretch="Fill"
                         Source= "W:/New Folder/freeze.svg">
        </svgc:SvgViewbox>
    </Grid>

But it works with SharpVectors 1.5!

Maybe related to some font definition in SVG?

[kkwpsv]

It may be realted to regular expression backtracking.

[marksolbergerbjorkerot]

Reproduced fail during css-parsing with the following data:
failed-svg-regexp.zip. RegEx.Match hangs and gets caught in a loop during css-processing in CssUnknownRule

[paulushub]

@marksolbergerbjorkerot Thanks for tracking this issue. There is another problem with this issue; the original SVG test file contains embedded WOFF2 format font, which is not fully supported by the SharpVectors. I am currently trying to complete that support and then take on the CSS parsing.

[marksolbergerbjorkerot]

@paulushub - it seems that CssRuleList never breaks the while-loop when no at-rules have been able to be parsed. It just keeps looping the same css over and over. Changing the UnknownCssRule regex-pattern no ^@[^;]+;? (making the last semi-colon optional) will render a match on the rule for cases where no semicolon exists and the while-loop will break.

[paulushub]

@marksolbergerbjorkerot I have completed the WOFF1/WOFF2 decoder codes and started testing this issue.
It seems the only fix required here is _reSplitCss in the CssStyleDeclaration.
Changing this to the fix in your fork/commit (change _reSplitCss by removing match any) seems to resolve both issues reported above.

private static readonly Regex _reSplitCss = new Regex(@"([^:\s]+)*\s*:\s*([^;]+);");

// changed to

private static readonly Regex _reSplitCss = new Regex(@"([^:\s]+)\s*:\s*([^;]+);");

[paulushub]

@kkwpsv @alo00 @marksolbergerbjorkerot It seems this issue is resolved by the latest commit. Please can you verify this fix.

@kkwpsv The embedded WOFF2 fonts are never used. Are you using these fonts? The fonts were decoded and successfully tested, but no verification is done in your test file, since there is no text to be rendered.

[kkwpsv]

I have test the latest version with my sample file, it works fine.
The svg file is not from myself, i don't know why it embed font and not use.
I have modified it to use font embeded. It seems also works fine.

svg with woff2 sample.zip

[paulushub]

@kkwpsv Thanks for the updates.

[Whiletru3]

Is there any plan for a new release including this fix ?

Thanks

[paulushub]

@Whiletru3 Will trying to get it out by Monday. Currently, busy looking for a new job 😢

[Whiletru3]

@paulushub Thanks a lot :) Good luck for your search 👍