1474821 - "Use system font size" causes text elements to get cut off (on some pages)

Status: RESOLVED DUPLICATE of bug 1428670

(Core :: Layout, defect)

Description

[nyanpasu64]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/67.0.3396.99 Safari/537.36

Steps to reproduce:

- Open menu/Settings/Accessibility
- Enable "Use system font size" (causes bug to happen)
- Go to http://www.jaytheham.com/zcw/Majora%27s_Mask_Crooked_Cartridge

(this website does not use web fonts, and defaults to Clear Sans)


Actual results:

Every single element's text is cut off at the right.
- The title is truncated to "Majora's Mask Crooked Cart"
- "Instructions" is cut off to "Instructioı..." (most of the n is missing)
- If you scroll down, "48 Ocarinas" is truncated around "na", while the colon and all subsequent text appear normally.



Expected results:

Each element's text is not truncated.

Comment 1

[nyanpasu64]

The bug only appears if you load a page with "Use system font size" checked.

The bug ends if you subsequently uncheck it. Even entering Menu/Settings/Accessibility and toggling "Use system font size" off and on will fix the bug, until page is reloaded.

If I toggle "Use system font size" off and on, then reload the page, all bounding boxes "shrink" horizontally *and* vertically as the bug reappears. This suggests Firefox is using the unscaled font size to calculate the size of each element.

- On http://www.jaytheham.com/zcw/Majora%27s_Mask_Crooked_Cartridge_-_Bowless_Link , the bullet points are unaffected by the bug and do not shrink horizontally or vertically.

Each individual line of paragraphs is cutoff individually, indicating each individual line's bounding box is calculated erroneously (impacting line wrapping). "Fixing" the bug decreases words per line, reloading the page increases words per line.

If I visit a page with a long title (like http://www.jaytheham.com/zcw/Majora%27s_Mask_Crooked_Cartridge_-_Bowless_Link ), it appears that

Comment 2

[Jan Henning [:JanH]]

Might be a duplicate of bug 1428670, but I need to check the regression range to see if it's indeed the same bug.

Comment 3

[Jan Henning [:JanH]]

That bug is reaching its anniversary, which means the inbound builds are just about to expire, but it is indeed the same regression range.