Simple gradient in pdf displaced vertically on import.

Migrated from https://bugs.launchpad.net/inkscape/+bug/1272071 (reported 2014-01-23, mathog)

Summary:

  • Import a pdf with two simple gradients displaces the gradient positions, breaking the appearance of vertical gradients
  • pdf uses /pattern. Other pdfs created from svg export don't have this problem.

Steps to reproduce:

What happened?

  • Notice top rectangle is solid gray (instead of gradient from top to bottom)
  • Both gradients have been displaced vertically.

Some notes:

  • File originally an Inkscape export of gradients.svg
    • gradients both have a gradientTransform on them (scale + near 0 displacement)
    • gradients are both opaque, which simplifies logic
    • no other transforms
    • Settings used: PDF 1.5, only rasterize filter effects checked, resolution 90, output page size = use document's page size, bleed margin 0.0, limit export = blank
    • Can't recreate in 1.1-dev (838ae0f22d, 2020-07-14, custom) or 0.92.3 ppa. I can't read pdf binary, but a file comparison shows Mathog's pdfs have /Pattern in it, while my exports don't. For 0.92.3, libcairo2=1.15.10-2ubuntu0.1 libpoppler73=0.62.0-2ubuntu2.10 . I guess the same versions are used for my 1.1-dev build?
    • Can recreate in 0.48.5-1 x32 on Windows 10 64
    • image
    • New exports have gradient positions correctly on roundhouse trip
  • Internal import is fine

What should have happened?

  • no gradient displacement

Version Info:

  • Inkscape 1.1-dev (838ae0f22d, 2020-07-14, custom) Linux Mint 19.1 (also failed to reproduce pdf file from svg)
  • Inkscape 0.92.3 (2405546, 2018-03-11) ppa Linux Mint 19.1 (also failed to reproduce pdf file from svg)
  • Inkscape 1.0 (4035a4fb49, 2020-05-01) Arch (inkscape 1.0-5 from extras) (also failed to reproduce pdf file from svg)
  • Inkscape 1.0 (4035a4fb49, 2020-05-01) Windows 10 x64 (also failed to reproduce pdf file from svg)
  • Inkscape 0.92.0 r15299 x64 7z Windows 10 x64 (also failed to reproduce pdf file from svg)
  • Inkscape 0.91-1 r13725 x64 7z archive Windows 10 x64 (also failed to reproduce pdf file from svg)

Not replicated 0.48.5-1 r10040 x32 7z archive (on Windows 10 x64), but exporting to pdf DID reproduce the pdf