ebook-convert pdf plugin does not render dasharray

[jimbojw]

Version: 3.21
Platform: Ubuntu

Problem: Attempting to convert an epub to PDF using ebook-convert. The epub file contains inline SVG with <line> elements that have a stroke-dasharray attribute. The example SVG on MDN's stroke-dasharray page exhibits the problem[1].

Root cause: in calibre/ebooks/pdf/render/graphics.py, in the apply_stroke() method, in the section on applying the dash pattern, the code checks pen.style() against a list of several Qt::PenStyle enum values[2]. However, the actual pen.style() value for an SVG element with a dasharray attribute is Qt.CustomDashLine, which is not in the checked list.

Solution: Add a check for Qt.CustomDashLine and if present, use the pen.dashPattern() and pen.dashOffset() values for the dashArray and dashPhase parameters to the 'd' operator respectively.

Caveat: Once you make this change, you'll also need to make sure to reset the dash style for the next path. I've found that always setting the dash style solves this problem.

[1] https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/stroke-dasharray
[2] https://doc.qt.io/archives/qt-4.8/qt.html#PenStyle-enum

[jimbojw (jimbojw)]

Created PR 951 to fix this issue. https://github.com/kovidgoyal/calibre/pull/951

[Kovid Goyal (kovid)]

Fixed in branch master. The fix will be in the next release. calibre is usually released every alternate Friday.

 status fixreleased