While Zen's soft and round rendering looks nice on some fonts or sites, some other fonts or contrast scenarios look horrible. Especially some (demi-)bold text or headings are coarse.
A quick search shows I'm far from the first person to notice. This community however has no info on it yet, so here we go.
Below is a compilation of setting recommendations I found in posts and bug reports about font rendering issues in Firefox in general and Zen specifically. I suggest playing around to see what works best for you.
The only setting that's a must:
- Go to about:config
- Accept the risks and continue. You daredevil!
- Search for "rounded"
- Double-click zen.view.experimental-rounded-view to set it to false
EDIT: For those interested at all. The only thing from my original post that really contributes to alleviating the issue is the setting mentioned above. For the full fix for blurry fonts and bad scrolling performance follow this comment. Instead of the disable rounded corners mod you can also use the 'No Gaps' mod and disable the rounded corners in its settings.
Not a consistent or real fix. Can be set to preference.
I also use this one:
- Search for "font_rendering"
- gfx.font_rendering.cleartype_params.rendering_mode set to 5
These are found in many recommendations, but really are about preference more than anything:
- gfx.font_rendering.directwrite.bold_simulation to 2
- gfx.font_rendering.directwrite.use_gdi_table_loading to false
- gfx.font_rendering.cleartype_params.cleartype_level to 100 (default -1 appears to have logic on when to enable/disable, but defaults to 100 when enabled)
- gfx.font_rendering.cleartype_params.enhanced_contrast to 50 (default -1 is 100)
I used these at first but noticed these are really hit or miss depending on the site you're on. The last two options can mess up (thin) fonts when transparency is involved, like when transparent gradients are used to fade out text.
After a couple of edits I've landed on the settings above. Comparing back-to-back with vanilla Firefox, it's clear that after disabling the Zen-specific rounded view any remaining font rendering issues are generic to the Firefox base it's built on. Problematic cases where settings like rendering_mode help, were seen (and improved) in both browsers.
A good example of problematic sites are some of the apps to access this Lemmy instance (a.lemmy.zip and t.lemmy.zip) or the KeePass site, the download page in particular.