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Glossary

What is SVG in EPUB?

Updated:

SVG (Scalable Vector Graphics) is the XML vector image format allowed in EPUB 3, either as image files or inline in content documents. Unlike JPEG or PNG, it stays sharp at any size.

Why it matters when you convert a PDF to EPUB

Charts and diagrams in a PDF are often vector drawings; converting them to SVG keeps them sharp, while rasterising them is simpler and more compatible with older readers. Fixed-layout pages built as SVG need a viewBox.

How EpubCC handles it: the engine does not produce SVG. Images are taken from the PDF as JPEG or PNG with a longest side of 1,600 pixels, and drawings that are not image objects (lines and shapes drawn directly on the page, as in many charts) are not carried into the EPUB. Chart-heavy PDFs are therefore a known weak spot, and the free sample shows how a given chart comes out.

Related terms

EPUBCheck messages about this

  • HTM-048 SVG Fixed-Layout Documents must have a "viewBox" attribute (on the outermost "svg" element).
  • RSC-015 A fragment identifier is required for svg use tag references.
  • RSC-009 A non-SVG image resource should not be defined with a fragment identifier.
  • RSC-014 Fragment identifier defines an incompatible resource type.
  • OPF-014 The property "…" should be declared in the OPF file.
  • OPF-073 External identifiers must not appear in the document type declaration.
  • HTM_062 SVG "xlink:href" attribute is deprecated; an "href" attribute should be used instead.
  • MED_018 URL fragment should be an SVG fragment identifier, but found '#…'.
  • ACC-011 SVG hyperlink has no accessible name

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FAQ

What is SVG in EPUB?

SVG (Scalable Vector Graphics) is the XML vector image format allowed in EPUB 3, either as image files or inline in content documents. Unlike JPEG or PNG, it stays sharp at any size.