ZIm/crates/terminal/src/terminal_settings.rs
Richard Feldman 9b7632d5f6
Automatically adjust ANSI color contrast (#34033)
Closes #33253 in a way that doesn't regress #32175 - namely,
automatically adjusts the contrast between the foreground and background
text in the terminal such that it's above a certain threshold. The
threshold is configurable in settings, and can be set to 0 to turn off
this feature and use exactly the colors the theme specifies even if they
are illegible.

## One Light Theme Before
<img width="220" alt="Screenshot 2025-07-07 at 6 00 47 PM"
src="https://github.com/user-attachments/assets/096754a6-f79f-4fea-a86e-cb7b8ff45d60"
/>

(Last row is highlighted because otherwise the text is unreadable; the
foreground and background are the same color.)

## One Light Theme After

(This is with the new default contrast adjustment setting.)

<img width="215" alt="Screenshot 2025-07-07 at 6 22 02 PM"
src="https://github.com/user-attachments/assets/b082fefe-76f5-4231-b704-ff387983a3cb"
/>

This approach was inspired by @mitchellh's use of automatic contrast
adjustment in [Ghostty](https://ghostty.org/) - thanks, Mitchell! The
main difference is that we're using APCA's formula instead of WCAG for
[these
reasons](https://khan-tw.medium.com/wcag2-are-you-still-using-it-ui-contrast-visibility-standard-readability-contrast-f34eb73e89ee).

Release Notes:

- Added automatic dynamic contrast adjustment for terminal foreground
and background colors
2025-07-07 22:39:11 +00:00

443 lines
15 KiB
Rust

use alacritty_terminal::vte::ansi::{
CursorShape as AlacCursorShape, CursorStyle as AlacCursorStyle,
};
use collections::HashMap;
use gpui::{AbsoluteLength, App, FontFallbacks, FontFeatures, FontWeight, Pixels, px};
use schemars::JsonSchema;
use serde_derive::{Deserialize, Serialize};
use settings::SettingsSources;
use std::path::PathBuf;
use task::Shell;
use theme::FontFamilyName;
#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
#[serde(rename_all = "snake_case")]
pub enum TerminalDockPosition {
Left,
Bottom,
Right,
}
#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
pub struct Toolbar {
pub breadcrumbs: bool,
}
#[derive(Clone, Debug, Deserialize)]
pub struct TerminalSettings {
pub shell: Shell,
pub working_directory: WorkingDirectory,
pub font_size: Option<Pixels>,
pub font_family: Option<FontFamilyName>,
pub font_fallbacks: Option<FontFallbacks>,
pub font_features: Option<FontFeatures>,
pub font_weight: Option<FontWeight>,
pub line_height: TerminalLineHeight,
pub env: HashMap<String, String>,
pub cursor_shape: Option<CursorShape>,
pub blinking: TerminalBlink,
pub alternate_scroll: AlternateScroll,
pub option_as_meta: bool,
pub copy_on_select: bool,
pub keep_selection_on_copy: bool,
pub button: bool,
pub dock: TerminalDockPosition,
pub default_width: Pixels,
pub default_height: Pixels,
pub detect_venv: VenvSettings,
pub max_scroll_history_lines: Option<usize>,
pub toolbar: Toolbar,
pub scrollbar: ScrollbarSettings,
pub minimum_contrast: f32,
}
#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
pub struct ScrollbarSettings {
/// When to show the scrollbar in the terminal.
///
/// Default: inherits editor scrollbar settings
pub show: Option<ShowScrollbar>,
}
#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
pub struct ScrollbarSettingsContent {
/// When to show the scrollbar in the terminal.
///
/// Default: inherits editor scrollbar settings
pub show: Option<Option<ShowScrollbar>>,
}
/// When to show the scrollbar in the terminal.
///
/// Default: auto
#[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
#[serde(rename_all = "snake_case")]
pub enum ShowScrollbar {
/// Show the scrollbar if there's important information or
/// follow the system's configured behavior.
Auto,
/// Match the system's configured behavior.
System,
/// Always show the scrollbar.
Always,
/// Never show the scrollbar.
Never,
}
#[derive(Clone, Debug, Default, Serialize, Deserialize, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum VenvSettings {
#[default]
Off,
On {
/// Default directories to search for virtual environments, relative
/// to the current working directory. We recommend overriding this
/// in your project's settings, rather than globally.
activate_script: Option<ActivateScript>,
directories: Option<Vec<PathBuf>>,
},
}
pub struct VenvSettingsContent<'a> {
pub activate_script: ActivateScript,
pub directories: &'a [PathBuf],
}
impl VenvSettings {
pub fn as_option(&self) -> Option<VenvSettingsContent<'_>> {
match self {
VenvSettings::Off => None,
VenvSettings::On {
activate_script,
directories,
} => Some(VenvSettingsContent {
activate_script: activate_script.unwrap_or(ActivateScript::Default),
directories: directories.as_deref().unwrap_or(&[]),
}),
}
}
}
#[derive(Clone, Copy, Debug, Default, Serialize, Deserialize, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum ActivateScript {
#[default]
Default,
Csh,
Fish,
Nushell,
PowerShell,
}
#[derive(Clone, Debug, Default, Serialize, Deserialize, JsonSchema)]
pub struct TerminalSettingsContent {
/// What shell to use when opening a terminal.
///
/// Default: system
pub shell: Option<Shell>,
/// What working directory to use when launching the terminal
///
/// Default: current_project_directory
pub working_directory: Option<WorkingDirectory>,
/// Sets the terminal's font size.
///
/// If this option is not included,
/// the terminal will default to matching the buffer's font size.
pub font_size: Option<f32>,
/// Sets the terminal's font family.
///
/// If this option is not included,
/// the terminal will default to matching the buffer's font family.
pub font_family: Option<FontFamilyName>,
/// Sets the terminal's font fallbacks.
///
/// If this option is not included,
/// the terminal will default to matching the buffer's font fallbacks.
#[schemars(extend("uniqueItems" = true))]
pub font_fallbacks: Option<Vec<FontFamilyName>>,
/// Sets the terminal's line height.
///
/// Default: comfortable
pub line_height: Option<TerminalLineHeight>,
pub font_features: Option<FontFeatures>,
/// Sets the terminal's font weight in CSS weight units 0-900.
pub font_weight: Option<f32>,
/// Any key-value pairs added to this list will be added to the terminal's
/// environment. Use `:` to separate multiple values.
///
/// Default: {}
pub env: Option<HashMap<String, String>>,
/// Default cursor shape for the terminal.
/// Can be "bar", "block", "underline", or "hollow".
///
/// Default: None
pub cursor_shape: Option<CursorShape>,
/// Sets the cursor blinking behavior in the terminal.
///
/// Default: terminal_controlled
pub blinking: Option<TerminalBlink>,
/// Sets whether Alternate Scroll mode (code: ?1007) is active by default.
/// Alternate Scroll mode converts mouse scroll events into up / down key
/// presses when in the alternate screen (e.g. when running applications
/// like vim or less). The terminal can still set and unset this mode.
///
/// Default: on
pub alternate_scroll: Option<AlternateScroll>,
/// Sets whether the option key behaves as the meta key.
///
/// Default: false
pub option_as_meta: Option<bool>,
/// Whether or not selecting text in the terminal will automatically
/// copy to the system clipboard.
///
/// Default: false
pub copy_on_select: Option<bool>,
/// Whether to keep the text selection after copying it to the clipboard.
///
/// Default: false
pub keep_selection_on_copy: Option<bool>,
/// Whether to show the terminal button in the status bar.
///
/// Default: true
pub button: Option<bool>,
pub dock: Option<TerminalDockPosition>,
/// Default width when the terminal is docked to the left or right.
///
/// Default: 640
pub default_width: Option<f32>,
/// Default height when the terminal is docked to the bottom.
///
/// Default: 320
pub default_height: Option<f32>,
/// Activates the python virtual environment, if one is found, in the
/// terminal's working directory (as resolved by the working_directory
/// setting). Set this to "off" to disable this behavior.
///
/// Default: on
pub detect_venv: Option<VenvSettings>,
/// The maximum number of lines to keep in the scrollback history.
/// Maximum allowed value is 100_000, all values above that will be treated as 100_000.
/// 0 disables the scrolling.
/// Existing terminals will not pick up this change until they are recreated.
/// See <a href="https://github.com/alacritty/alacritty/blob/cb3a79dbf6472740daca8440d5166c1d4af5029e/extra/man/alacritty.5.scd?plain=1#L207-L213">Alacritty documentation</a> for more information.
///
/// Default: 10_000
pub max_scroll_history_lines: Option<usize>,
/// Toolbar related settings
pub toolbar: Option<ToolbarContent>,
/// Scrollbar-related settings
pub scrollbar: Option<ScrollbarSettingsContent>,
/// The minimum APCA perceptual contrast between foreground and background colors.
///
/// APCA (Accessible Perceptual Contrast Algorithm) is more accurate than WCAG 2.x,
/// especially for dark mode. Values range from 0 to 106.
///
/// Based on APCA Readability Criterion (ARC) Bronze Simple Mode:
/// https://readtech.org/ARC/tests/bronze-simple-mode/
/// - 0: No contrast adjustment
/// - 45: Minimum for large fluent text (36px+)
/// - 60: Minimum for other content text
/// - 75: Minimum for body text
/// - 90: Preferred for body text
///
/// Default: 0 (no adjustment)
pub minimum_contrast: Option<f32>,
}
impl settings::Settings for TerminalSettings {
const KEY: Option<&'static str> = Some("terminal");
type FileContent = TerminalSettingsContent;
fn load(sources: SettingsSources<Self::FileContent>, _: &mut App) -> anyhow::Result<Self> {
let settings: Self = sources.json_merge()?;
// Validate minimum_contrast for APCA
if settings.minimum_contrast < 0.0 || settings.minimum_contrast > 106.0 {
anyhow::bail!(
"terminal.minimum_contrast must be between 0 and 106, but got {}. \
APCA values: 0 = no adjustment, 75 = recommended for body text, 106 = maximum contrast.",
settings.minimum_contrast
);
}
Ok(settings)
}
fn import_from_vscode(vscode: &settings::VsCodeSettings, current: &mut Self::FileContent) {
let name = |s| format!("terminal.integrated.{s}");
vscode.f32_setting(&name("fontSize"), &mut current.font_size);
if let Some(font_family) = vscode.read_string(&name("fontFamily")) {
current.font_family = Some(FontFamilyName(font_family.into()));
}
vscode.bool_setting(&name("copyOnSelection"), &mut current.copy_on_select);
vscode.bool_setting("macOptionIsMeta", &mut current.option_as_meta);
vscode.usize_setting("scrollback", &mut current.max_scroll_history_lines);
match vscode.read_bool(&name("cursorBlinking")) {
Some(true) => current.blinking = Some(TerminalBlink::On),
Some(false) => current.blinking = Some(TerminalBlink::Off),
None => {}
}
vscode.enum_setting(
&name("cursorStyle"),
&mut current.cursor_shape,
|s| match s {
"block" => Some(CursorShape::Block),
"line" => Some(CursorShape::Bar),
"underline" => Some(CursorShape::Underline),
_ => None,
},
);
// they also have "none" and "outline" as options but just for the "Inactive" variant
if let Some(height) = vscode
.read_value(&name("lineHeight"))
.and_then(|v| v.as_f64())
{
current.line_height = Some(TerminalLineHeight::Custom(height as f32))
}
#[cfg(target_os = "windows")]
let platform = "windows";
#[cfg(target_os = "linux")]
let platform = "linux";
#[cfg(target_os = "macos")]
let platform = "osx";
#[cfg(target_os = "freebsd")]
let platform = "freebsd";
// TODO: handle arguments
let shell_name = format!("{platform}Exec");
if let Some(s) = vscode.read_string(&name(&shell_name)) {
current.shell = Some(Shell::Program(s.to_owned()))
}
if let Some(env) = vscode
.read_value(&name(&format!("env.{platform}")))
.and_then(|v| v.as_object())
{
for (k, v) in env {
if v.is_null() {
if let Some(zed_env) = current.env.as_mut() {
zed_env.remove(k);
}
}
let Some(v) = v.as_str() else { continue };
if let Some(zed_env) = current.env.as_mut() {
zed_env.insert(k.clone(), v.to_owned());
} else {
current.env = Some([(k.clone(), v.to_owned())].into_iter().collect())
}
}
}
}
}
#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, JsonSchema, Default)]
#[serde(rename_all = "snake_case")]
pub enum TerminalLineHeight {
/// Use a line height that's comfortable for reading, 1.618
#[default]
Comfortable,
/// Use a standard line height, 1.3. This option is useful for TUIs,
/// particularly if they use box characters
Standard,
/// Use a custom line height.
Custom(f32),
}
impl TerminalLineHeight {
pub fn value(&self) -> AbsoluteLength {
let value = match self {
TerminalLineHeight::Comfortable => 1.618,
TerminalLineHeight::Standard => 1.3,
TerminalLineHeight::Custom(line_height) => f32::max(*line_height, 1.),
};
px(value).into()
}
}
#[derive(Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum TerminalBlink {
/// Never blink the cursor, ignoring the terminal mode.
Off,
/// Default the cursor blink to off, but allow the terminal to
/// set blinking.
TerminalControlled,
/// Always blink the cursor, ignoring the terminal mode.
On,
}
#[derive(Clone, Copy, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum AlternateScroll {
On,
Off,
}
#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum WorkingDirectory {
/// Use the current file's project directory. Will Fallback to the
/// first project directory strategy if unsuccessful.
CurrentProjectDirectory,
/// Use the first project in this workspace's directory.
FirstProjectDirectory,
/// Always use this platform's home directory (if it can be found).
AlwaysHome,
/// Always use a specific directory. This value will be shell expanded.
/// If this path is not a valid directory the terminal will default to
/// this platform's home directory (if it can be found).
Always { directory: String },
}
// Toolbar related settings
#[derive(Clone, Debug, Default, Serialize, Deserialize, JsonSchema, PartialEq, Eq)]
pub struct ToolbarContent {
/// Whether to display the terminal title in breadcrumbs inside the terminal pane.
/// Only shown if the terminal title is not empty.
///
/// The shell running in the terminal needs to be configured to emit the title.
/// Example: `echo -e "\e]2;New Title\007";`
///
/// Default: true
pub breadcrumbs: Option<bool>,
}
#[derive(Clone, Copy, Debug, Default, Serialize, Deserialize, PartialEq, Eq, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum CursorShape {
/// Cursor is a block like `█`.
#[default]
Block,
/// Cursor is an underscore like `_`.
Underline,
/// Cursor is a vertical bar like `⎸`.
Bar,
/// Cursor is a hollow box like `▯`.
Hollow,
}
impl From<CursorShape> for AlacCursorShape {
fn from(value: CursorShape) -> Self {
match value {
CursorShape::Block => AlacCursorShape::Block,
CursorShape::Underline => AlacCursorShape::Underline,
CursorShape::Bar => AlacCursorShape::Beam,
CursorShape::Hollow => AlacCursorShape::HollowBlock,
}
}
}
impl From<CursorShape> for AlacCursorStyle {
fn from(value: CursorShape) -> Self {
AlacCursorStyle {
shape: value.into(),
blinking: false,
}
}
}