Description: Fonts are rendered poorly when using fractional scaling (e.g. 120% as opposed to integer scaling like 100%, 200%, 300%). Some fonts look worse than Times New Roman, but I used Times New Roman in my screenshots due to its ubiquity. Steps to Reproduce: 1. Set your display scaling to 100%, 200% or 300% and zoom so a document is a fixed size. 2. Set your display scaling to a fractional scaling value like 120%, 125% etc. and zoom so the document appears at the same size on the same display. Actual Results: Fonts look blurry and/or misshappen when fractional scaling is used. Expected Results: Font always looks the same, smooth and crisp, when rendered at the same size on the same display, no matter the Scale factor. Reproducible: Always User Profile Reset: No Additional Info: The issue appears in both GTK and QT, but I have only tested in KDE Plasma (not Gnome for example).
Created attachment 194724 [details] 120% Fractional Scaling Poor Font Rendering Please view at 100% zoom. The screenshot does not actually show exactly how the font rendered, but it is good enough to compare with the other screenshot.
Created attachment 194725 [details] 200% Scaling Good Font Rendering Please view at 100% zoom. The screenshot does not actually show exactly how the font rendered, but it is good enough to compare with the other screenshot.
(In reply to miafr30m from comment #2) > Created attachment 194725 [details] > 200% Scaling Good Font Rendering > > Please view at 100% zoom. > > The screenshot does not actually show exactly how the font rendered, but it > is good enough to compare with the other screenshot. Sorry, I copy and pasted the comment. The 200% scaling screenshot DOES show the font as it was rendered on my screen; it is the 120% scaling screenshot that does not.
Sorry, Something I missed is that you should restart LibreOffice between changing scaling factor
A font where it is very noticeable is Sabon Bold. This font doesn't render too well in the first place but is extra misshapen with fractional scaling. Unfortunately I could not capture this in a screenshot.
tested on Ubuntu 22.04 with Wayland and: Version: 24.2.4.2 (X86_64) / LibreOffice Community Build ID: 51a6219feb6075d9a4c46691dcfe0cd9c4fff3c2 CPU threads: 8; OS: Linux 6.5; UI render: default; VCL: gtk3 Locale: en-AU (en_AU.UTF-8); UI: en-US Calc: CL threaded I can't reproduce - or maybe I can't see the difference. Can you please be more specific about the issue, maybe annotating the screenshots side-by-side? And please share the full version info from Help > About LibreOffice. Thank you!
Unfortunately(In reply to Stéphane Guillou (stragu) from comment #6) > tested on Ubuntu 22.04 with Wayland and: > > Version: 24.2.4.2 (X86_64) / LibreOffice Community > Build ID: 51a6219feb6075d9a4c46691dcfe0cd9c4fff3c2 > CPU threads: 8; OS: Linux 6.5; UI render: default; VCL: gtk3 > Locale: en-AU (en_AU.UTF-8); UI: en-US > Calc: CL threaded > > I can't reproduce - or maybe I can't see the difference. Can you please be > more specific about the issue, maybe annotating the screenshots side-by-side? > > And please share the full version info from Help > About LibreOffice. > > Thank you! I just opened up a document to test again and the rendering has changed. This presumably is due to the KDE Plasma 6.1.1 update. The issue with inaccurate font shapes seems to be gone. However text now looks slightly soft at any fractional scaling level compared to integer scaling. Fonts now look better on my 4K screen which I run at 120% scaling, but worse on my tablet which I run at 195%. Previously when the scaling was close to 200% the font looked both smoother and crisper and more true to shape, but now on both displays it looks true to shape but a little soft. (I still consider this an improvement since being true to shape is more important to me than sharpness) I still stand by my initial hypothesis that the font is being rendered at an integer resolution and then downscaled – it just looks like the downscaling filter has been modified to now include more anti-aliasing.
Created attachment 195071 [details] 120% Plasma 6.1.1 Sabon Bold
Created attachment 195072 [details] 200% Plasma 6.1.1 Sabon Bold
Created attachment 195073 [details] 195% Tablet Plasma 6.1.1
Created attachment 195074 [details] 200% Tablet Plasma 6.1.1
The blurriness is most noticeable in the comparison between 195% and 200% on my tablet.
I can see the difference in sharpness between 195% in attachment 195073 [details] (blurrier) and 200% in attachment 195074 [details] (sharper). I can also see a slight difference with Ubuntu 22.04 + GNOME 42.9 + Wayland, comparing 100% and 175% (the UI only allow .25 increments). Version: 25.2.0.0.alpha0+ (X86_64) / LibreOffice Community Build ID: 5bf58785ba2831de4efc2afe9df463b4a753ccb1 CPU threads: 8; OS: Linux 6.5; UI render: default; VCL: gtk3 Locale: en-AU (en_AU.UTF-8); UI: en-US Calc: CL threaded But the same happens to e.g. the flashing cursor and the margin markers, and your screenshot shows the same issue with the toolbar icons. So isn't this a more general issue? Does it happen with other apps?