minimising output file size

[ParaplegicRacehorse]

Can the completed XHTML and CSS be passed through minify/tidy procedures before creating the archive? Likewise, can fonts be subset instead of embedding the whole thing? Images, too. Epub and KF8 are already small compared to PDF, but it's somewhat impolite to include more than what's needed in the archive.

Should be pretty easy to achieve?

for each (stylesdir/*.css)
  cssnano
for each (*.xhtml)
  html-minifier
for each (images/*.png)
  optipng
for each (images/*.jpg)
  imagemagik yada yada

[mojavelinux]

kindlegen actually does this already, afaik. So this would be more for the native EPUB output. Does seem like a good idea, though.

[slonopotamus]

Unlike web stuff, EPUB3 is a compressed format, so gains from compression are not going to be that great. And we have higher penalty for using non-Ruby software because we cannot install it automatically and would have to ask each user to install it on their own. I'd say that current book sizes are "good enough".

[slonopotamus]

Starting with c39d2159a8c329e2e2179a12c6cd7f4b39898f74, we output css files in compressed form (no comments and redundant newlines).

[slonopotamus]

I've tried minimizing HTML using

      def postprocess_xhtml content
        if @format == :kf8
          # TODO: convert regular expressions to constants
          content = content
            .gsub(/<img([^>]+) style="width: (\d\d)%;"/, '<img\1 style="width: \2%; height: \2%;"')
            .gsub(/<script type="text\/javascript">.*?<\/script>\n?/m, '')
        end

        doc = Nokogiri::XML.parse(content)
        doc.search('//comment()').remove
        doc.search('//text()[normalize-space()=""]').remove
        result = doc.to_xml(save_with: Nokogiri::XML::Node::SaveOptions::AS_XML)
        result.to_ios
      end

But... That resulted in 707KB -> 706KB total size for git-as-svn doc book and breakage of <pre> formatting. I don't think it is worth the effort and CPU cycles.

[slonopotamus]

I'd like to claim this issue is resolved.