Comment 23 for bug 1174909

Since 1.12.3, cairo cannot render fine lines to pdf. 1.12.2 was the last version that worked.

http://cgit.freedesktop.org/cair/diff/?id=bdf83008f4b2c723fd8e65e2a92bc47a2e7bc442

introduced this code in cairo-compositor.c:_cairo_compositor_stroke

   if (_cairo_pen_vertices_needed (tolerance, style->line_width/2, ctm) <= 1)
        return CAIRO_INT_STATUS_NOTHING_TO_DO;

The idea was to avoid lines that would be invisible when rasterized. While this is a valid logic for raster backends, it is a bad idea for PDF output. There we want to see all fine lines.

My specific use case is generating a lasercutter drawing for an Epilog Zing laser with inkscape. There the hardware would raster anything thicker than 0.02mm, and cut 0.01mm or below. 1.12.3 skips lines below 0.036mm, 1.13.1 skips lines below 0.018mm -- which is still not enough to safely drive my lasercutter.

See also https://bugs.launchpad.net/inkscape/+bug/1174909

Check out the attached reproducer.