It appears that the global settings don't have `zoom` as a setting property. Try using `HtmlToPdfObject#zoomFactor` instead, like so:
HtmlToPdf.create()
.pageSize(PdfPageSize.A4)
.object(HtmlToPdfObject.forHtml(html)
.zoomFactor(10))
.convert(destination);
Let me know if this works out for you.
Originally posted by @benbarkay in #17 (comment)