Blurry FLTK 1.4 fonts

Compared with FLTK 1.3 I see that in FLTK 1.4.4 and FLTK from git fonts look more blurry.

I suspect this has to do with how the hinting and antialiasing is being done as well as the sub-pixel placement of each glyph.

Title	Blurry FLTK 1.4 fonts
Author	Rodrigo Arias Mallo
Created	Sun, 22 Feb 2026 22:40:08 +0100
State	closed

For Xorg, FLTK 1.3 seems to take the font configuration from .Xresources (I can alter the hinting this way). I can reproduce the same blurry problems with the font FLTK test if I open the same font "Dejavu Sans (book)".

Rodrigo Arias Mallo on Sun, 01 Mar 2026 19:06:09 +0100

FLTK issue: https://github.com/fltk/fltk/issues/1365

After careful observation, this problem is not caused by a misconfiguration of hinting or antialiasing. The problem is that the rendering of the text is placed with a half pixel misalignment, which causes the edge of the characters to become blurry.

The problem is only present when using the Pango/Cairo rendering backend, switching to Xft avoids it.

This is a FLTK bug and has been fixed in:

FLTK 1.5 branch https://github.com/fltk/fltk/commit/486da9376d5e32a9bff2bf5446d0bd0e0db7cb20
FLTK 1.4 branch https://github.com/fltk/fltk/commit/17b30b55e39418b6a56c047f896df7f86ba4189d

It is planned to be released in the FLTK 1.4.5 release, so we don't need to do anything additional on Dillo. Affected versions 1.4.0 to 1.4.4 with the Pango backend will render blurry text.