feat(cosmic-theme): produce QPalette ini for more compatibility

cosmic-theme/src/output/mod.rs

@@ -46,8 +46,10 @@ impl Theme {
     pub fn write_exports(&self) -> Result<(), OutputError> {
         let gtk_res = self.write_gtk4();
         let qt_res = self.write_qt();
+        let qt56ct_res = self.write_qt56ct();
         gtk_res?;
         qt_res?;
+        qt56ct_res?;
         Ok(())
     }
 
@@ -56,8 +58,10 @@ impl Theme {
     pub fn reset_exports() -> Result<(), OutputError> {
         let gtk_res = Theme::reset_gtk();
         let qt_res = Theme::reset_qt();
+        let qt56ct_res = Theme::reset_qt56ct();
         gtk_res?;
         qt_res?;
+        qt56ct_res?;
         Ok(())
     }
 }

cosmic-theme/src/output/qt56ct_output.rs

@@ -1,8 +1,11 @@
 use crate::Theme;
 use configparser::ini::Ini;
+use palette::{Mix, Srgba, WithAlpha, rgb::Rgba};
 use std::{
     fs::{self, File},
+    io::Write,
     path::PathBuf,
+    vec,
 };
 
 use super::{OutputError, qt_settings_ini_style};
@@ -15,7 +18,116 @@ impl Theme {
     /// Increment this value when changes to qt{5,6}ct.conf are needed.
     /// If the config's version is outdated, we update several sections.
     /// Otherwise, only the light/dark mode is updated.
-    const COSMIC_QT_VERSION: u64 = 1;
+    const COSMIC_QT_VERSION: u64 = 2;
+
+    /// Produces a QPalette ini file for qt5ct and qt6ct.
+    ///
+    /// Example file: https://github.com/trialuser02/qt6ct/blob/master/colors/airy.conf
+    #[must_use]
+    #[cold]
+    pub fn as_qpalette(&self) -> String {
+        let lightest = if self.is_dark {
+            self.background.on
+        } else {
+            self.background.base
+        };
+        let darkest = if self.is_dark {
+            self.background.base
+        } else {
+            self.background.on
+        };
+        let active = QPaletteGroup {
+            window_text: self.background.on,
+            button: self.button.base,
+            light: self.button.base.mix(lightest, 0.1),
+            midlight: self.button.base.mix(lightest, 0.05),
+            dark: self.button.base.mix(darkest, 0.1),
+            mid: self.button.base.mix(darkest, 0.05),
+            text: self.background.component.on,
+            bright_text: lightest,
+            button_text: self.button.on,
+            base: self.background.component.base,
+            window: self.background.base,
+            shadow: darkest,
+            highlight: self.background.component.selected,
+            highlighted_text: self.background.component.selected_text,
+            link: self.link_button.on,
+            link_visited: self.link_button.on.mix(self.secondary.component.base, 0.2),
+            alternate_base: self.background.base.mix(self.accent.base, 0.05),
+            no_role: self.background.component.disabled,
+            tool_tip_base: self.background.component.base,
+            tool_tip_text: self.background.component.on,
+            placeholder_text: self.background.component.on.with_alpha(0.5),
+        };
+        let inactive = QPaletteGroup {
+            window_text: active.window_text.with_alpha(0.8),
+            text: active.text.with_alpha(0.8),
+            highlighted_text: active.highlighted_text.with_alpha(0.8),
+            tool_tip_text: active.tool_tip_text.with_alpha(0.8),
+            ..active
+        };
+        let disabled = QPaletteGroup {
+            button: self.button.disabled,
+            text: self.background.component.on_disabled,
+            button_text: self.button.on_disabled,
+            base: self.background.component.disabled,
+            highlighted_text: active.highlighted_text.with_alpha(0.5),
+            link: self.link_button.on_disabled,
+            link_visited: self
+                .link_button
+                .on_disabled
+                .mix(self.secondary.component.disabled, 0.2),
+            alternate_base: self.background.base.mix(self.accent.disabled, 0.05),
+            tool_tip_base: self.background.component.disabled,
+            tool_tip_text: self.background.component.on_disabled,
+            placeholder_text: self.background.component.on_disabled.with_alpha(0.5),
+            ..inactive
+        };
+
+        format!(
+            r#"# GENERATED BY COSMIC
+
+[ColorScheme]
+active_colors={}
+disabled_colors={}
+inactive_colors={}
+"#,
+            active.as_list(),
+            disabled.as_list(),
+            inactive.as_list(),
+        )
+    }
+
+    /// Writes the QPalette ini files to:
+    /// - `~/.config/qt6ct/colors/`
+    /// - `~/.config/qt5ct/colors/`
+    #[cold]
+    pub fn write_qt56ct(&self) -> Result<(), OutputError> {
+        let qpalette = self.as_qpalette();
+        let qt5ct_res = self.write_ct("qt5ct", &qpalette);
+        let qt6ct_res = self.write_ct("qt6ct", &qpalette);
+        qt5ct_res?;
+        qt6ct_res?;
+        Ok(())
+    }
+    #[must_use]
+    #[cold]
+    fn write_ct(&self, ct: &str, qpalette: &str) -> Result<(), OutputError> {
+        let file_path = Self::get_qpalette_path(ct, self.is_dark)?;
+        let tmp_file_path = file_path.with_extension("conf.new");
+
+        let mut tmp_file = File::create(&tmp_file_path).map_err(OutputError::Io)?;
+        let res = tmp_file
+            .write_all(qpalette.as_bytes())
+            .and_then(|_| tmp_file.flush())
+            .and_then(|_| std::fs::rename(&tmp_file_path, file_path));
+        if let Err(e) = res {
+            _ = std::fs::remove_file(&tmp_file_path);
+            return Err(OutputError::Io(e));
+        }
+
+        Ok(())
+    }
 
     /// Edits qt{5,6}ct.conf to use COSMIC styles if needed.
     #[cold]
@@ -39,7 +151,7 @@ impl Theme {
             .map_err(OutputError::Ini)?
             .unwrap_or_default();
 
-        let color_scheme_path = Self::get_kcolorscheme_path(is_dark)?;
+        let color_scheme_path = Self::get_qpalette_path(ct, is_dark)?;
         let icon_theme = if is_dark { "breeze-dark" } else { "breeze" };
 
         ini.set(
@@ -91,11 +203,48 @@ impl Theme {
         Ok(())
     }
 
+    /// Reset the applied qt56ct config by removing COSMIC-specific entries from the config file.
+    #[cold]
+    pub fn reset_qt56ct() -> Result<(), OutputError> {
+        let qt5ct_res = Self::reset_ct("qt5ct");
+        let qt6ct_res = Self::reset_ct("qt6ct");
+        qt5ct_res?;
+        qt6ct_res?;
+        Ok(())
+    }
+    #[must_use]
+    #[cold]
+    fn reset_ct(ct: &str) -> Result<(), OutputError> {
+        let path = Self::get_conf_path(ct)?;
+        let file_content = fs::read_to_string(&path).map_err(OutputError::Io)?;
+        let mut ini = Ini::new_cs();
+        ini.read(file_content).map_err(OutputError::Ini)?;
+
+        let old_version = ini
+            .getuint("Appearance", "cosmic_qt_version")
+            .map_err(OutputError::Ini)?
+            .unwrap_or_default();
+        if old_version == 0 {
+            return Ok(());
+        }
+
+        ini.remove_key("Appearance", "cosmic_qt_version");
+        ini.remove_key("Appearance", "color_scheme_path");
+        ini.remove_key("Appearance", "icon_theme");
+
+        ini.pretty_write(path, &qt_settings_ini_style())
+            .map_err(OutputError::Io)?;
+        Ok(())
+    }
+
     /// Returns the file paths of the form `~/.config/ct/ct.conf`:
     /// e.g. `~/.config/qt6ct/qt6ct.conf`.
     ///
     /// The file and its parent directory are created if they don't exist.
+    #[cold]
     fn get_conf_path(ct: &str) -> Result<PathBuf, OutputError> {
+        assert!(ct == "qt5ct" || ct == "qt6ct");
+
         let Some(mut config_dir) = dirs::config_dir() else {
             return Err(OutputError::MissingConfigDir);
         };
@@ -111,4 +260,128 @@ impl Theme {
 
         Ok(file_path)
     }
+
+    /// Gets a path like `~/.config/qt6ct/colors/CosmicDark.conf`
+    ///
+    /// Its parent directory is created if it doesn't exist.
+    #[cold]
+    fn get_qpalette_path(ct: &str, is_dark: bool) -> Result<PathBuf, OutputError> {
+        assert!(ct == "qt5ct" || ct == "qt6ct");
+
+        let Some(mut config_dir) = dirs::config_dir() else {
+            return Err(OutputError::MissingConfigDir);
+        };
+        config_dir.push(&ct);
+        config_dir.push("colors");
+        if !config_dir.exists() {
+            fs::create_dir_all(&config_dir).map_err(OutputError::Io)?;
+        }
+
+        let file_name = if is_dark {
+            "CosmicDark.conf"
+        } else {
+            "CosmicLight.conf"
+        };
+
+        Ok(config_dir.join(file_name))
+    }
+}
+
+/// Defines the different symbolic color roles used in current GUIs.
+///
+/// qt5ct and qt6ct consume this as a list of colors, ordered by ColorRole:
+/// - https://doc.qt.io/qt-6/qpalette.html#ColorRole-enum
+/// - https://doc.qt.io/archives/qt-5.15/qpalette.html#ColorRole-enum
+struct QPaletteGroup {
+    /// A general foreground color.
+    window_text: Srgba,
+    /// The general button background color.
+    button: Srgba,
+    /// Lighter than [button] color, used mostly for 3D bevel and shadow effects.
+    light: Srgba,
+    /// Between [button] and [light], used mostly for 3D bevel and shadow effects.
+    midlight: Srgba,
+    /// Darker than [button], used mostly for 3D bevel and shadow effects.
+    dark: Srgba,
+    /// Between [button] and [dark], used mostly for 3D bevel and shadow effects.
+    mid: Srgba,
+    /// The foreground color used with [base].
+    text: Srgba,
+    /// A text color that is very different from [window_text], and contrasts well with e.g. [dark].
+    /// Typically used for text that needs to be drawn where [text] or [window_text] would give poor contrast, such as on pressed push buttons.
+    bright_text: Srgba,
+    /// A foreground color used with the [button] color.
+    button_text: Srgba,
+    /// Used mostly as the background color for text entry widgets, but can also be used for other painting -
+    /// such as the background of combobox drop down lists and toolbar handles.
+    base: Srgba,
+    /// A general background color.
+    window: Srgba,
+    /// A very dark color, used mostly for 3D bevel and shadow effects.
+    /// Opaque black by default.
+    shadow: Srgba,
+    /// A color to indicate a selected item or the current item.
+    highlight: Srgba,
+    /// A text color that contrasts with [highlight].
+    highlighted_text: Srgba,
+    /// A text color used for unvisited hyperlinks.
+    link: Srgba,
+    /// A text color used for already visited hyperlinks.
+    link_visited: Srgba,
+    /// Used as the alternate background color in views with alternating row colors.
+    alternate_base: Srgba,
+    /// No role; this special role is often used to indicate that a role has not been assigned.
+    no_role: Srgba,
+    /// Used as the background color for QToolTip and QWhatsThis.
+    /// Tool tips use the inactive color group of QPalette, because tool tips are not active windows.
+    tool_tip_base: Srgba,
+    /// Used as the foreground color for QToolTip and QWhatsThis.
+    /// Tool tips use the inactive color group of QPalette, because tool tips are not active windows.
+    tool_tip_text: Srgba,
+    /// Used as the placeholder color for various text input widgets.
+    placeholder_text: Srgba,
+    // /// [accent] only exists since Qt 6.6. Including it here breaks qt5ct.
+    // /// When omitted, it defaults to [highlight].
+    // accent: Srgba,
+}
+
+impl QPaletteGroup {
+    /// Returns a comma-separated list of the colors as hex codes.
+    /// E.g. `#ff000000, #ffdcdcdc, ...`
+    fn as_list(&self) -> String {
+        let colors = vec![
+            to_argb_hex(self.window_text),
+            to_argb_hex(self.button),
+            to_argb_hex(self.light),
+            to_argb_hex(self.midlight),
+            to_argb_hex(self.dark),
+            to_argb_hex(self.mid),
+            to_argb_hex(self.text),
+            to_argb_hex(self.bright_text),
+            to_argb_hex(self.button_text),
+            to_argb_hex(self.base),
+            to_argb_hex(self.window),
+            to_argb_hex(self.shadow),
+            to_argb_hex(self.highlight),
+            to_argb_hex(self.highlighted_text),
+            to_argb_hex(self.link),
+            to_argb_hex(self.link_visited),
+            to_argb_hex(self.alternate_base),
+            to_argb_hex(self.no_role),
+            to_argb_hex(self.tool_tip_base),
+            to_argb_hex(self.tool_tip_text),
+            to_argb_hex(self.placeholder_text),
+        ];
+        colors.join(", ")
+    }
+}
+
+/// Converts a color to a hex string in the format `#AARRGGBB`.
+/// Do not use [to_hex] since that uses the format `RRGGBBAA`.
+fn to_argb_hex(c: Srgba) -> String {
+    let c_u8: Rgba<palette::encoding::Srgb, u8> = c.into_format();
+    format!(
+        "#{:02x}{:02x}{:02x}{:02x}",
+        c_u8.alpha, c_u8.red, c_u8.green, c_u8.blue
+    )
 }

cosmic-theme/src/output/qt_output.rs

@@ -305,7 +305,7 @@ widgetStyle=qt6ct-style
     }
 
     /// Gets a path like `~/.local/share/color-schemes/CosmicDark.colors`
-    pub fn get_kcolorscheme_path(is_dark: bool) -> Result<PathBuf, OutputError> {
+    fn get_kcolorscheme_path(is_dark: bool) -> Result<PathBuf, OutputError> {
         let Some(mut data_dir) = dirs::data_dir() else {
             return Err(OutputError::MissingDataDir);
         };