SVG tag parsing

[rbfrank]

Ebookmaker apparently does not accept svg files created with tex2svg. These generated tags result in CRITICAL errors: role, Focusable, aria-labelledby, and aria-hidden.

Should ebookmaker be parsing SVG image files? And if it does, is there a description of tags it will or will not allow? From that list, it seems that aria-hidden should be allowed to control exposure to screen readers.

[eshellman]

Focusable is not included in SVG 1.1, which is used by EPUB.
If you get the other error (making sure that the file is parsed as html, not xml) please post the sample file generating the errors and reopen the issue.

[rbfrank]

altitude2.zip

output.txt

[eshellman]

that is html flavored SVG - put it in the html file and it works fine.

[rbfrank]

I'm confused. The zip file provided above has an HTML file that uses that SVG. Is that what you mean by "put it in the html file" or is there some other way other than as a normal illustration? And does "it works fine" mean I can ignore the CRITICAL errors in output.txt?

[eshellman]

embed the svg/html code in the html document.

[rtonsing]

Now that I looked more into SVG, I understand that it is XML code, and could be edited.

But I don't think it is reasonable to expect an average user to edit a file generated by an imaging application, much less pull out code to put in the HTML. Which code? All of it? Any but the most simple images quickly become gibberish to any but an expert, I certainly am not comfortable with it.

If it is necessary to parse & check SVG code for epub, we need to understand why, and have some guidelines on which editors generate good code. Users should not be expected to manually edit the files, any more than JPG or PNG files.

My 2c.

[eshellman]

I've not tried tex2svg, but if it is not making svg 1.1. files or valid html5 files, we can't recommend its use. perhaps it has config options.

[rbfrank]

The tex2svg npm package is supposed to default to 1.1. It is configurable as well. But on further investigation, it's considered a relatively inactive project. Maybe we shouldn't be hitching our SVG wagon to that tool anyway. I don't know of anything better, though.

We, or more specifically DP, need a "HowTo" for making usable SVG 1.1 files from LaTeX source.

[jhellingman]

I ran into the same issue, and with chatGTP hacked together a little XSLT transformation to remove the offending attributes, as well as a perl script to apply it to a whole folder of svg files.

<xsl:stylesheet version="3.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:svg="http://www.w3.org/2000/svg">

  <!-- Identity transform: copy everything by default -->
  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()"/>
    </xsl:copy>
  </xsl:template>

  <!-- Remove aria-* attributes -->
  <xsl:template match="@*[starts-with(name(), 'aria-')]"/>

  <!-- Remove role and focusable attributes from svg elements only -->
  <xsl:template match="svg:svg/@role"/>
  <xsl:template match="svg:svg/@focusable"/>

</xsl:stylesheet>

And

use strict;
use warnings;
use File::Copy;

my $saxonHome = $ENV{'SAXON_HOME'};
my $javaOptions = '-Xms2048m -Xmx4096m -Xss1024k ';

my $java      = "java $javaOptions";
my $saxon     = "$java -jar " . $saxonHome . "/saxon9he.jar ";

# XSLT file (adjust if needed)
my $xslt_file = 'cleansvg.xsl';

# Check if the XSLT file exists
die "XSLT file '$xslt_file' not found\n" unless -e $xslt_file;

# Process each .svg file in the current directory
foreach my $svg_file (glob("*.svg")) {
    my $backup_file = "$svg_file.bak";
    my $temp_output = "$svg_file.tmp";

    print "Processing $svg_file -> (backup: $backup_file)\n";

    # Run the transformation
    my $cmd = "$saxon -s:$svg_file -xsl:$xslt_file -o:$temp_output";
    system($cmd) == 0 or do {
        warn "Failed to process $svg_file: $!\n";
        next;
    };

    # Rename original to .bak
    move($svg_file, $backup_file) or do {
        warn "Failed to backup $svg_file to $backup_file: $!\n";
        next;
    };

    # Move cleaned output to original name
    move($temp_output, $svg_file) or do {
        warn "Failed to write cleaned file to $svg_file: $!\n";
        # Restore from backup in case of error
        move($backup_file, $svg_file);
    };
}

[eshellman]

similar issues in #296
the issues that @jhellingman 's script could be included in the script posted there. given that the tex workflow is still being developed, I think it's premature to have ebookmaker process svg files.