freetype_load_flags now defaults to NO_HINTING

wez · Jan 29, 2024 · 616b218 · 616b218
1 parent 69e0858
commit 616b218
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Showing 3 changed files with 29 additions and 5 deletions.
diff --git a/config/src/font.rs b/config/src/font.rs
@@ -250,7 +250,7 @@ bitflags! {
     // Note that these are strongly coupled with deps/freetype/src/lib.rs,
     // but we can't directly reference that from here without making config
     // depend on freetype.
-    #[derive(Default,  FromDynamic, ToDynamic)]
+    #[derive(FromDynamic, ToDynamic)]
     #[dynamic(try_from="String", into="String")]
     pub struct FreeTypeLoadFlags: u32 {
         /// FT_LOAD_DEFAULT
@@ -271,6 +271,12 @@ bitflags! {
     }
 }
 
+impl Default for FreeTypeLoadFlags {
+    fn default() -> Self {
+        Self::NO_HINTING
+    }
+}
+
 impl From<FreeTypeLoadFlags> for String {
     fn from(val: FreeTypeLoadFlags) -> Self {
         val.to_string()

diff --git a/docs/changelog.md b/docs/changelog.md
@@ -22,7 +22,10 @@ usually the best available version.
 As features stabilize some brief notes about them will accumulate here.
 
 #### Changed
-* Not yet!
+* The default for
+  [freetype_load_flags](config/lua/config/freetype_load_flags.md) is now
+  `NO_HINTING`. #4874
+
 #### New
 #### Fixed
 * macOS: System LastResort font would be taken in preference to other fonts

diff --git a/docs/config/lua/config/freetype_load_flags.md b/docs/config/lua/config/freetype_load_flags.md
@@ -14,9 +14,12 @@ be combined.
 Available flags are:
 
 * `DEFAULT` - This is the default!
-* `NO_HINTING` - Disable hinting. This generally generates ‘blurrier’
-  bitmap glyph when the glyph is rendered in any of the
-  anti-aliased modes.
+* `NO_HINTING` - Disable hinting. The freetype documentation says that this
+  generally generates ‘blurrier’ bitmap glyph when the glyph is rendered in any of the
+  anti-aliased modes, but that was written for rasterizing direct to bitmaps.
+  In the context of wezterm where we are rasterizing to a texture that is then
+  sampled and applied to a framebuffer through vertices on the GPU, the hinting
+  process can be counter-productive and result in unexpect visual artifacts.
 * `NO_BITMAP` - don't load any pre-rendered bitmap strikes
 * `FORCE_AUTOHINT` - Use the freetype auto-hinter rather than the font's
   native hinter.
@@ -30,3 +33,15 @@ Available flags are:
 config.freetype_load_flags = 'NO_HINTING|MONOCHROME'
 ```
 
+{{since('nightly')}}
+
+The default value has changed to `NO_HINTING` as that generally works
+more predictably and with fewer surprising artifacts.
+
+In earlier versions, it is recommended that you configure this
+explicitly:
+
+```lua
+config.freetype_load_flags = 'NO_HINTING'
+```
+