Add Constant easing function

refs: https://github.com/wez/wezterm/issues/1738

config/src/bell.rs

@@ -9,6 +9,7 @@ pub enum EasingFunction {
     EaseIn,
     EaseInOut,
     EaseOut,
+    Constant,
 }
 impl_lua_conversion!(EasingFunction);
 
@@ -22,6 +23,7 @@ impl EasingFunction {
         }
 
         match self {
+            Self::Constant => 0.,
             Self::Linear => cubic_bezier(0., 0., 1.0, 1.0, position),
             Self::CubicBezier(a, b, c, d) => cubic_bezier(*a, *b, *c, *d, position),
             Self::Ease => cubic_bezier(0.25, 0.1, 0.25, 1.0, position),

docs/config/lua/config/animation_fps.md

@@ -11,6 +11,13 @@ utilization.
 If you are running with a CPU renderer (eg: you have [front_end](front_end.md)
 = `"Software"`, or your system doesn't have a GPU), then setting `animation_fps
 = 1` is recommended, as doing so will disable easing effects and use
-transitions.
+transitions:
 
+```lua
+return {
+  animation_fps = 1,
+  cursor_blink_ease_in = "Constant",
+  cursor_blink_ease_out = "Constant",
+}
+```
 

docs/config/lua/config/visual_bell.md

@@ -27,6 +27,7 @@ The following easing functions are supported:
 * `EaseInOut` - The fade starts slowly, speeds up, and then slows down towards the end.
 * `EaseOut` - The fade starts abruptly, and then progressively slows down towards the end.
 * `{CubicBezier={0.0, 0.0, 0.58, 1.0}}` - an arbitrary cubic bezier with the specified parameters.
+* `Constant` - Evaluates as 0 regardless of time. Useful to implement a step transition at the end of the duration. (*Since: nightly builds only*)
 
 The following configuration enables a low intensity visual bell that takes a total of 300ms to "flash" the screen: