WPS Office bold fonts problems

I use WPS Office for my work and so far have been quite happy with it. However, I noticed that it has some problem with certain fonts, when bold. I am not sure when this started, but apparently it happened after a certain freetype update. So, I decided to look around for a solution.

Take a look at the screenshot below, that’s what I am talking about:

I found these discussions, at OpenSUSE forums and NixOS GutHub. The latter suggested a problem with FreeType after version 2.13.0 (at the moment, freetype is at version 2.13.2 on CRUX 3.7). The discussion also points at FreeType GitLab, where a proposed patch for the issue was rejected.

So, I had several options: downgrade FreeType to 2.13.0 system-wide, patch FreeType 2.13.2 system-wide, use 2.13.0 for WPS Office only or use a patched 2.13.2 for WPS Office only. I decided to try the last solution, so here’s the patch:

diff -pruN orig/src/base/ftsynth.c new/src/base/ftsynth.c
--- orig/src/base/ftsynth.c	2023-03-16 06:17:48.000000000 +0200
+++ new/src/base/ftsynth.c	2024-07-22 11:48:00.374834820 +0300
@@ -98,7 +98,22 @@
   FT_EXPORT_DEF( void )
   FT_GlyphSlot_Embolden( FT_GlyphSlot  slot )
   {
-    FT_GlyphSlot_AdjustWeight( slot, 0x0AAA, 0x0AAA );
+    FT_UShort        units_per_EM;
+    FT_Size_Metrics* metrics;
+    FT_Fixed         xdelta, ydelta;
+
+    if ( !slot )
+      return;
+
+    units_per_EM = slot->face->units_per_EM;
+    metrics      = &( slot->face->size->metrics );
+
+    xdelta = FT_MulFix( units_per_EM, metrics->x_scale / 24 ) * 1024 /
+             (FT_Pos)metrics->x_ppem;
+    ydelta = FT_MulFix( units_per_EM, metrics->y_scale / 24 ) * 1024 /
+             (FT_Pos)metrics->y_ppem;
+
+    FT_GlyphSlot_AdjustWeight( slot, xdelta, ydelta );
   }
 

So, my WPS office port builds an patched version of FreeType and places the library in the office6 dir. It works as before and so far, I have not had issues with the program. In any case, the patched lib is isolated from the rest of the system.

To fix this on another distribution, e.g. Ubuntu, let’s simply use the old freetype. Try the following:

wget https://sourceforge.net/projects/freetype/files/freetype2/2.13.0/freetype-2.13.0.tar.xz
tar xvf freetype-2.13.0.tar.xz 
meson setup freetype-2.13.0 build
meson compile -C build
sudo cp -a build/{libfreetype.so,libfreetype.so.6,libfreetype.so.6.19.0} /opt/kingsoft/wps-office/office6/