Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Remove fallback code for glyph indices#30168

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to ourterms of service andprivacy statement. We’ll occasionally send you account related emails.

Already on GitHub?Sign in to your account

Open
QuLogic wants to merge2 commits intomatplotlib:text-overhaul
base:text-overhaul
Choose a base branch
Loading
fromQuLogic:no-glyph-fallback

Conversation

QuLogic
Copy link
Member

PR summary

Glyph indices are specific to each font. It does not make sense to fall back based on glyph index to another font.

This could only really be populated by callingFT2Font.set_text, but even that was fragile. If a fallback font was used for a character with the same glyph index as a previous character in the main font, then these lookups could be overwritten to the fallback instead of the main font, with a completely different character!

Fortunately, nothing actually uses or requires a fallback through glyph indices, and this is all internal to the extension.

Note to reviewers: the second commit here is just the last commit fromthetext-overhaul-images branch, but is not actually relevant here. Please only review the first commit as the second will be dropped before merging. If you prefer, I can targetmain, but I thought this was relevant to thetext-overhaul branch.

PR checklist

Glyph indices are specific to each font. It does not make sense to fallback based on glyph index to another font.This could only really be populated by calling `FT2Font.set_text`, buteven that was fragile. If a fallback font was used for a character withthe same glyph index as a previous character in the main font, thenthese lookups could be overwritten to the fallback instead of the mainfont, with a completely different character!Fortunately, nothing actually uses or requires a fallback through glyphindices.
@QuLogicQuLogic added this to thev3.11.0 milestoneJun 12, 2025
@github-project-automationgithub-project-automationbot moved this toWaiting for other PR inFont and text overhaulJun 12, 2025
@QuLogicQuLogic moved this fromWaiting for other PR toReady for Review inFont and text overhaulJun 12, 2025
@QuLogic
Copy link
MemberAuthor

QuLogic commentedJun 13, 2025•
edited
Loading

As an example, in DejaVu Sans, the letter A is glyph index 36:

>>> dejavu = FT2Font('lib/matplotlib/mpl-data/fonts/ttf/DejaVuSans.ttf')>>> dejavu.get_char_index(ord('A'))36

which has metrics like:

>>> g = dejavu.load_glyph(36)>>> g.bbox(6, 0, 519, 576)

In the Last Resort font, the Tibetan block is glyph index 36:

>>> lastresort = FT2Font('lib/matplotlib/mpl-data/fonts/ttf/LastResortHE-Regular.ttf')>>> lastresort.set_charmap(0)>>> lastresort.get_char_index(ord('\U00000F00'))36>>> g = lastresort.load_glyph(36)>>> g.bbox(72, -167, 808, 578)

So if we have a string with both using fallbacks, then the last glyph 'wins':

>>> font = FT2Font('lib/matplotlib/mpl-data/fonts/ttf/DejaVuSans.ttf', _fallback_list=[lastresort])>>> font.set_text('A\U00000F00')array([[  0.,   0.],       [528.,   0.]])>>> g = font.load_glyph(36)>>> g.bbox(72, -167, 808, 578)

If we had multiple fonts in the fallbacks, and multiple characters in those fonts that used the same glyph index, then lookup would depend on the order of characters in the text!

Sign up for freeto join this conversation on GitHub. Already have an account?Sign in to comment
Reviewers

@anntzeranntzeranntzer approved these changes

Assignees
No one assigned
Projects
Status: Ready for Review
Milestone
v3.11.0
Development

Successfully merging this pull request may close these issues.

2 participants
@QuLogic@anntzer
[8]ページ先頭
©2009-2025 Movatter.jp