Fix colors with Terminal.app's Clear Dark theme (#728)

Author: lhecker

.vscode/launch.json

@@ -2,7 +2,7 @@
     "version": "0.2.0",
     "configurations": [
         {
-            "name": "Launch Debug (Windows)",
+            "name": "Launch edit (Windows)",
             "preLaunchTask": "rust: cargo build",
             "type": "cppvsdbg",
             "request": "launch",
@@ -14,7 +14,7 @@
             ],
         },
         {
-            "name": "Launch Debug (GDB)",
+            "name": "Launch edit (GDB, Linux)",
             "preLaunchTask": "rust: cargo build",
             "type": "cppdbg",
             "request": "launch",
@@ -27,15 +27,28 @@
             ],
         },
         {
-            "name": "Launch Debug (LLDB)",
+            // NOTE for macOS: In order for this task to work you have to:
+            // 1. Run the "Fix externalConsole on macOS" task once
+            // 2. Add the following to your VS Code settings:
+            //    "lldb-dap.environment": {
+            //        "LLDB_LAUNCH_FLAG_LAUNCH_IN_TTY": "YES"
+            //    }
+            "name": "Launch edit (lldb-dap, macOS)",
             "preLaunchTask": "rust: cargo build",
-            "type": "lldb",
+            "type": "lldb-dap",
             "request": "launch",
             "program": "${workspaceFolder}/target/debug/edit",
             "cwd": "${workspaceFolder}",
             "args": [
                 "${workspaceFolder}/crates/edit/src/bin/edit/main.rs"
             ],
-        }
+        },
+        {
+            // This is a workaround for https://github.com/microsoft/vscode-cpptools/issues/5079
+            "name": "Fix externalConsole on macOS",
+            "type": "node-terminal",
+            "request": "launch",
+            "command": "osascript -e 'tell application \"Terminal\"\ndo script \"echo hello\"\nend tell'"
+        },
     ]
 }

crates/edit/Cargo.toml

@@ -15,6 +15,7 @@ name = "lib"
 harness = false
 
 [features]
+# Display editor latency in the top-right corner
 debug-latency = []
 
 [dependencies]

crates/edit/src/bin/edit/main.rs

@@ -12,8 +12,6 @@ mod localization;
 mod state;
 
 use std::borrow::Cow;
-#[cfg(feature = "debug-latency")]
-use std::fmt::Write;
 use std::path::{Path, PathBuf};
 use std::time::Duration;
 use std::{env, process};
@@ -23,7 +21,7 @@ use draw_filepicker::*;
 use draw_menubar::*;
 use draw_statusbar::*;
 use edit::framebuffer::{self, IndexedColor};
-use edit::helpers::{CoordType, KIBI, MEBI, MetricFormatter, Rect, Size};
+use edit::helpers::*;
 use edit::input::{self, kbmod, vk};
 use edit::oklab::StraightRgba;
 use edit::tui::*;
@@ -178,6 +176,8 @@ fn run() -> apperr::Result<()> {
 
             #[cfg(feature = "debug-latency")]
             {
+                use std::fmt::Write as _;
+
                 // Print the number of passes and latency in the top right corner.
                 let time_end = std::time::Instant::now();
                 let status = time_end - time_beg;

crates/edit/src/framebuffer.rs

@@ -107,6 +107,8 @@ pub struct Framebuffer {
     /// of the palette as [dark, light], unless the palette is recognized
     /// as a light them, in which case it swaps them.
     auto_colors: [StraightRgba; 2],
+    /// Above this lightness value, we consider a color to be "light".
+    auto_color_threshold: f32,
     /// A cache table for previously contrasted colors.
     /// See: <https://fgiesen.wordpress.com/2019/02/11/cache-tables/>
     contrast_colors: [Cell<(StraightRgba, StraightRgba)>; CACHE_TABLE_SIZE],
@@ -125,6 +127,7 @@ impl Framebuffer {
                 DEFAULT_THEME[IndexedColor::Black as usize],
                 DEFAULT_THEME[IndexedColor::BrightWhite as usize],
             ],
+            auto_color_threshold: 0.5,
             contrast_colors: [const { Cell::new((StraightRgba::zero(), StraightRgba::zero())) };
                 CACHE_TABLE_SIZE],
             background_fill: DEFAULT_THEME[IndexedColor::Background as usize],
@@ -145,7 +148,17 @@ impl Framebuffer {
             self.indexed_colors[IndexedColor::Black as usize],
             self.indexed_colors[IndexedColor::BrightWhite as usize],
         ];
-        if !Self::is_dark(self.auto_colors[0]) {
+
+        // It's not guaranteed that Black is actually dark and BrightWhite light (vice versa for a light theme).
+        // Such is the case with macOS 26's "Clear Dark" theme (and probably a lot other themes).
+        // Its black is #35424C (l=0.3716; oof!) and bright white is #E5EFF5 (l=0.9464).
+        // If we have a color such as #43698A (l=0.5065), which is l>0.5 ("light") and need a contrasting color,
+        // we need that to be #E5EFF5, even though that's also l>0.5. With a midpoint of 0.659, we get that right.
+        let lightness = self.auto_colors.map(|c| c.as_oklab().lightness());
+        self.auto_color_threshold = (lightness[0] + lightness[1]) * 0.5;
+
+        // Ensure [0] is dark and [1] is light.
+        if lightness[0] > lightness[1] {
             self.auto_colors.swap(0, 1);
         }
     }
@@ -346,15 +359,12 @@ impl Framebuffer {
     #[cold]
     fn contrasted_slow(&self, color: StraightRgba) -> StraightRgba {
         let idx = (color.to_ne() as usize).wrapping_mul(HASH_MULTIPLIER) >> CACHE_TABLE_SHIFT;
-        let contrast = self.auto_colors[Self::is_dark(color) as usize];
+        let is_dark = color.as_oklab().lightness() < self.auto_color_threshold;
+        let contrast = self.auto_colors[is_dark as usize];
         self.contrast_colors[idx].set((color, contrast));
         contrast
     }
 
-    fn is_dark(color: StraightRgba) -> bool {
-        color.as_oklab().lightness() < 0.5
-    }
-
     /// Blends the given sRGB color onto the background bitmap.
     ///
     /// TODO: The current approach blends foreground/background independently,

crates/edit/src/helpers.rs

@@ -82,6 +82,9 @@ pub struct Size {
 }
 
 impl Size {
+    pub const MIN: Self = Self { width: 0, height: 0 };
+    pub const MAX: Self = Self { width: CoordType::MAX, height: CoordType::MAX };
+
     pub fn as_rect(&self) -> Rect {
         Rect { left: 0, top: 0, right: self.width, bottom: self.height }
     }

crates/edit/src/sys/unix.rs

@@ -11,7 +11,7 @@ use std::fs::File;
 use std::mem::{self, ManuallyDrop, MaybeUninit};
 use std::os::fd::{AsRawFd as _, FromRawFd as _};
 use std::path::Path;
-use std::ptr::{self, NonNull, null_mut};
+use std::ptr::{NonNull, null_mut};
 use std::{thread, time};
 
 use stdext::arena::{Arena, ArenaString, scratch_arena};
@@ -203,7 +203,7 @@ pub fn read_stdin(arena: &Arena, mut timeout: time::Duration) -> Option<ArenaStr
                         tv_sec: timeout.as_secs() as libc::time_t,
                         tv_nsec: timeout.subsec_nanos() as libc::c_long,
                     };
-                    ret = libc::ppoll(&mut pollfd, 1, &ts, ptr::null());
+                    ret = libc::ppoll(&mut pollfd, 1, &ts, std::ptr::null());
                 }
                 #[cfg(not(target_os = "linux"))]
                 {

crates/stdext/src/arena/string.rs

@@ -95,6 +95,13 @@ impl<'a> ArenaString<'a> {
         }
     }
 
+    #[must_use]
+    pub fn from_iter<T: IntoIterator<Item = char>>(arena: &'a Arena, iter: T) -> Self {
+        let mut s = Self::new_in(arena);
+        s.extend(iter);
+        s
+    }
+
     /// It's empty.
     pub fn is_empty(&self) -> bool {
         self.vec.is_empty()
@@ -284,6 +291,18 @@ impl fmt::Write for ArenaString<'_> {
     }
 }
 
+impl Extend<char> for ArenaString<'_> {
+    fn extend<I: IntoIterator<Item = char>>(&mut self, iter: I) {
+        let iterator = iter.into_iter();
+        let (lower_bound, _) = iterator.size_hint();
+        self.reserve(lower_bound);
+        iterator.for_each(move |c| self.push(c));
+    }
+
+    // TODO: This is where I'd put `extend_one` and `extend_reserve` impls, *but as always*,
+    // essential stdlib functions are unstable and that means we can't have them.
+}
+
 #[macro_export]
 macro_rules! arena_format {
     ($arena:expr, $($arg:tt)*) => {{