Can you send me a screenshot of your problem. you should press (print) button to take quick screenshot.

Here is a screenshot. Verticals are "bolded" but curved and horizontals, as in this post AFAIK, are not. Thanks.

This could be related with the recent switch in Firefox 52+ from Cairo to Skia for canvas/content rendering.

Firefox 52+ has changed from Cairo to Skia for canvas/content rendering.

• https://www.mozilla.org/en-US/firefox/52.0/releasenotes/
• When not using Direct2D on Windows, Skia is used for content rendering

You can modify these gfx.*.azure.backends prefs on the about:config page to revert to the old font rendering swap the skia,cairo order to cairo,skia or remove the skia and leave cairo.

• gfx.canvas.azure.backends = direct2d1.1,cairo,skia
• gfx.content.azure.backends = direct2d1.1,cairo,skia

You can open the about:config page via the location/address bar.

You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

cor-el,

Thanks, I tried your suggestion but in this draft, for example, I still have the same issue.

Hi   !
You said that you bought a 'replacement PC', but didn't say whether it's a new one or a secondhand   .......
Would you take a look at this article   (just in case) :
Upgrade your graphics drivers to use hardware acceleration and WebGL

What font is Firefox using?

You can right-click and select "Inspect Element" to open the built-in Inspector with this element selected. You can check the font used for selected text in the Font tab in the right pane of the Inspector. Set devtools.fontinspector.enabled to true on the about:config page to enabled the Font tab.

• https://developer.mozilla.org/Tools/Page_Inspector
• https://developer.mozilla.org/Tools/Page_Inspector/How_to/View_fonts
• devtools.fontinspector.enabled = true

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

Thanks for the reply. The PC is a new one, in the box.

cor-el said

This could be related with the recent switch in Firefox 52+ from Cairo to Skia for canvas/content rendering.

Firefox 52+ has changed from Cairo to Skia for canvas/content rendering.

• https://www.mozilla.org/en-US/firefox/52.0/releasenotes/
• When not using Direct2D on Windows, Skia is used for content rendering

You can modify these gfx.*.azure.backends prefs on the about:config page to revert to the old font rendering swap the skia,cairo order to cairo,skia or remove the skia and leave cairo.

• gfx.canvas.azure.backends = direct2d1.1,cairo,skia
• gfx.content.azure.backends = direct2d1.1,cairo,skia

You can open the about:config page via the location/address bar.

You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

Thanks for the reply, and apologies for lateness in responding. I've been out of town.

The font is "Open Sans".