Add boot-time tweak 'nsh' to disable new sub-pixel hinting in freetype

Freetype has enabled a 'new style' of sub-pixel hinting, based on the
Infinality patch but simplified for speed.
Some people feel that this new type of hinting is resulting in worse font
rendering than with the old auto-hinter built into Freetype.
The new tweak 'nsh' effectively disables the new type of sub-pixel hinting
and makes Freetype fall back to the old behaviour.

Usage: add "tweaks=nsh" to the boot commandline of the Live OS.

2 files changed, 49 insertions, 0 deletions

diff --git a/README.txt b/README.txt
index 953a39a..42f2c2d 100644
--- a/README.txt
+++ b/README.txt
@@ -262,6 +262,7 @@ localhd => initialize RAID/LVM on local hard drives.
 
 tweaks=tweak1[,tweak2,[,...]] => Implemented tweaks:
   nga - no glamor 2D acceleration, avoids error "EGL_MESA_drm_image required".
+  nsh - no 'new style' sub-pixel hinting in freetype.
   tpb - enable TrackPoint scrolling while holding down middle mouse button.
   syn - start the syndaemon for better support of Synaptics touchpads.
   ssh - start the SSH server (disabled by default)
diff --git a/liveinit.tpl b/liveinit.tpl
index de23e24..e20eb61 100755
--- a/liveinit.tpl
+++ b/liveinit.tpl
@@ -77,6 +77,12 @@ LOCALHD=0
 # Usability tweaks:
 TWEAKS=""
 
+# Deal with freetype's sub-pixel hinting.
+# Enable the new v40 interpreter only if /etc/profile.d/freetype.sh is found.
+# Otherwise (or in case 'tweaks=nsh' is passed at boot) disable the new
+# interpreter and fall back to the old v35 interpreter.
+SPH=1
+
 # Perhaps we need to blacklist some kernel module(s):
 BLACKLIST=""
 
@@ -209,6 +215,7 @@ for ARG in $(cat /proc/cmdline); do
     tweaks=*)
       # Comma-separated set of usability tweaks.
       # nga: no glamor 2d acceleration.
+      # nsh: no sub-pixel hinting in freetype.
       # tpb: trackpoint scrolling while pressing middle mouse button.
       # syn: start synaptics daemon and extend X.Org capabilities.
       # ssh: start SSH daemon (disabled by default).
@@ -992,6 +999,8 @@ Section "Device"
   Option "AccelMethod" "none"
 EndSection
 EOT
+    elif [ "$TWEAK" = "nsh" ]; then
+      SPH=0
     elif [ "$TWEAK" = "tpb" ]; then
       # Enable scrolling with TrackPoint while pressing the middle mouse button.
       # Note: if this does not work for your TrackPoint,
@@ -1049,6 +1058,45 @@ EOT
     fi
   done # End Tweaks.
 
+  # After parsing the tweaks, we know what to do with freetype's rendering:
+  if [ ! -f /mnt/overlay/etc/profile.d/freetype.sh ]; then
+    # Old freetype - disable sub-pixel hinting:
+    SPH=0
+  fi
+  if [ $SPH -eq 1 ]; then
+    # Enable the new v40 interpreter in freetype:
+    sed -e 's/^ *[^# ]/#&/' -i /mnt/overlay/etc/profile.d/freetype.sh
+    cat <<EOT >> /mnt/overlay/etc/profile.d/freetype.sh
+export FREETYPE_PROPERTIES="truetype:interpreter-version=40"
+EOT
+    sed -e 's/^ *[^# ]/#&/' -i /mnt/overlay/etc/profile.d/freetype.csh
+    cat <<EOT >> /mnt/overlay/etc/profile.d/freetype.csh
+setenv FREETYPE_PROPERTIES "truetype:interpreter-version=40"
+EOT
+    # Adapt the font configuration:
+    ln -s /etc/fonts/conf.avail/10-hinting-slight.conf /mnt/overlay/etc/fonts/conf.d/
+    ln -s /etc/fonts/conf.avail/11-lcdfilter-default.conf /mnt/overlay/etc/fonts/conf.d/
+    cat <<EOT > /mnt/overlay/home/${LIVEUID}/.Xresources
+Xft.dpi: 96
+Xft.antialias: 1
+Xft.hinting: 1
+Xft.hintstyle: hintslight
+Xft.lcdfilter: lcddefault
+Xft.rgba: rgb
+Xft.autohint: 0
+EOT
+  elif [ -f /mnt/overlay/etc/profile.d/freetype.sh ]; then
+    # Explicitly configure the non-default old v35 interpreter in freetype:
+    sed -e 's/^ *[^# ]/#&/' -i /mnt/overlay/etc/profile.d/freetype.sh
+    cat <<EOT >> /mnt/overlay/etc/profile.d/freetype.sh
+export FREETYPE_PROPERTIES="truetype:interpreter-version=35"
+EOT
+    sed -e 's/^ *[^# ]/#&/' -i /mnt/overlay/etc/profile.d/freetype.csh
+    cat <<EOT >> /mnt/overlay/etc/profile.d/freetype.csh
+setenv FREETYPE_PROPERTIES "truetype:interpreter-version=35"
+EOT
+  fi # End Sub-Pixel Hinting
+
   # Blacklist kernel modules if requested:
   if [ ! -z "$BLACKLIST" ]; then
     mkdir -p /mnt/overlay/etc/modprobe.d