Fedora 35 vertical text test cases failing (render_test-glyph-y-pos, render_text-glyphs-combining, render_text-glyphs-vertical, render_test-rtl-vertical)

Reported by @shlomif in #2917

Steps to reproduce:

        ninja -j4 install && \
        ninja -j4 check \
        ; n --msg "Inkscape build finished"

What happened?

• Some test failures, all revolving around vertical text that is oriented like LTR text.

fedora_35_tests.zip

        Start 352: render_text-gzipped-svg-glyph
352/352 Test #352: render_text-gzipped-svg-glyph .......................................   Passed    0.46 sec

99% tests passed, 4 tests failed out of 352

Total Test time (real) = 107.97 sec

The following tests did not run:
         57 - cli_export-type_emf_check_output (Skipped)
         71 - cli_export-area-page_emf_check_output (Skipped)
        219 - cli_export-ignore-filters_emf_check_output (Skipped)
        253 - cli_export-extension_emf_check_output (Skipped)

The following tests FAILED:
        347 - render_test-glyph-y-pos (Failed)
        348 - render_text-glyphs-combining (Failed)
        349 - render_text-glyphs-vertical (Failed)
        351 - render_test-rtl-vertical (Failed)
Errors while running CTest
ninja: build stopped: subcommand failed.
shlomif[ink]:$trunk$

Bisection of pango indicates that the Fedora 35 rendering issues were introduced in https://gitlab.gnome.org/GNOME/pango/-/commit/ccb651dd2a876a4f4a4cb9351f05332173e709ba, https://gitlab.gnome.org/GNOME/pango/-/merge_requests/495

commit ccb651dd2a876a4f4a4cb9351f05332173e709ba (origin/advance-transform)
Author: Matthias Clasen <mclasen@redhat.com>
Date:   Fri Nov 5 06:57:44 2021 -0400

    Fix advance widths with transforms
    
    The hb_font_t we were passing to Harfbuzz
    for shaping was not taking context transforms
    into account, and therefore was not scaling
    advance widths as necessary. Always go through
    pangos glyph extents to fix this.
    
    Fixes: https://gitlab.gnome.org/GNOME/pango/-/issues/620

This change can also be seen in pango-view, though I can only figure it out for chinese text, of which, I'm not sure which rendering is more correct.

pango-view --gravity=west --font="Noto Sans CJK JP" --rotate=90 --text="㆕㆖㆘" gives the left rendering

pango-view --gravity=west --rotate=90 utils/test-chinese.txt (taken from https://gitlab.gnome.org/GNOME/pango/-/issues/423#note_608895, utils/test-chinese.txt referring to https://gitlab.gnome.org/GNOME/pango/-/blob/main/utils/test-chinese.txt) gives the left rendering

What should have happened?

• Tests pass

Inkscape Version and Operating System:

• Inkscape Version: 1.2-dev on Fedora 34. I don't have precise version info at hand, but let's say 1.2-dev (9a8a3d57, 2021-11-25)

added ImportanceMedium + 1 deleted label

mentioned in issue #2917

Well, pango on Windows and Arch are now on .50, which means this affects more users, raising priority

added ImportanceHigh label and removed ImportanceMedium label

changed milestone to %Inkscape 1.1.2

/cc @Tavmjong

@nathanal afaiu if it's "more correct" to have the glyphs closer to another, we would also be more correct, right ? (and would just need to update the tests ?)

The newer renderings we produce are further apart, and start at the wrong place (see text-glyphs-combine from the zip file) and look very wrong.

I can't tell which pango-view rendering is more correct, but the new behavior has the glyphs further apart. The right-most text in the screenshots is older behavior.

At least in Japanese (and I assume also in Chinese and Korean), character-to-character spacing should be tight. The new rendering is clearly wrong.

Pango issue that lead to change: https://gitlab.gnome.org/GNOME/pango/-/issues/620

An error in origin was fixed by Pango commit db4fde572907d837dd994df6c46b77a95b0079e9, included in 1.50.0. Fedora 35 currently has 1.49.3.

Windows experiences the bug and is on 1.50.

A bit easier for me to test, pango on Arch is on pango 1:1.50.1-1 and I also replicate

I've added some comments to https://gitlab.gnome.org/GNOME/pango/-/merge_requests/495

From the comments, looks like this has been resolved by a revert.

https://gitlab.gnome.org/GNOME/pango/-/merge_requests/556

Thanks for raising this issue upstream. It's included in 1.50.3, which is the current version in mingw. this should be fixed for the Windows release

mentioned in commit freedesktop-sdk/mirrors/gnome/pango@22f8df57

mentioned in commit freedesktop-sdk/mirrors/gnome/pango@f3819b39

closed

added rendering text labels