Use color scheme based on OS system dark/light mode preferences

.clang-format

@@ -95,7 +95,7 @@ IncludeCategories:
     Priority:  52
   - Regex:     '^<harfbuzz/'
     Priority:  53
-  - Regex:     '^<(QtCore|QtGui|QtWidgets|QtQml|QtQuick|QtNetwork|QtMultimedia)/'
+  - Regex:     '^<(QtCore|QtGui|QtDBus|QtWidgets|QtQml|QtQuick|QtNetwork|QtMultimedia)/'
     Priority:  64
   - Regex:     '^<catch2/'
     Priority:  70

.gitignore

@@ -15,6 +15,7 @@ _deps/**
 out
 out/**
 CMakeSettings.json
+vcpkg_installed/**
 
 # VIM: code completion / IntelliSense
 .clangd

docs/configuration/profiles.md

@@ -363,13 +363,27 @@ profiles:
 
 
 ### `colors`
-section in the configuration file allows you to specify the colorscheme to use for the terminal. Alternatively, you can inline the color definitions within this section.
+section in the configuration file allows you to specify the colorscheme to use for the terminal.
 ``` yaml
 profiles:
   profile_name:
     colors: "default"
 ```
 
+To make the terminal's color scheme dependant on OS appearance (dark and light mode) settings,
+you need to specify two color schemes:
+
+```yaml
+profiles:
+  profile_name:
+    colors:
+      dark: "some_dark_scheme_name"
+      light: "some_light_scheme_name"
+```
+
+With this, the terminal will use the color scheme as specified in `dark` when OS dark mode is on,
+and `light`'s color scheme otherwise.
+
 ### `hyperlink_decoration:`
 section in the configuration file allows you to configure the styling and colorization of hyperlinks when they are displayed in the terminal and when they are hovered over by the cursor.
 ``` yaml

docs/vt-extensions/color-palette-update-notifications.md

@@ -0,0 +1,40 @@
+# Dark and Light Mode detection
+
+Most modern operating systems and desktop environments do support Dark and Light themes,
+this includes at least MacOS, Windows, KDE Plasma, Gnome, and probably others.
+
+Some even support switching from dark to light and light to dark mode based on sun rise / sun set.
+
+In order to not make the terminal emulator look bad after such switch, we must
+enable the applications inside the terminal to detect when the terminal has
+updated the color palette. This may happen either due to the operaging system having
+changed the current theme or simply because the user has explicitly requested to
+reconfigure the currently used theme.
+
+Ideally we are getting CLI tools like [delta]() to query the theme mode before sending out RGB values
+to the terminal to make the output look more in line with the rest of the desktop.
+
+But also TUIs like vim should be able to reflect dark/light mode changes as soon as the
+desktop has charnged from light to dark and vice versa, e.g. to make it more pleasing to the eyes.
+
+## Query the current theme mode?
+
+Send `CSI ? 996 n` to the terminal to explicitly request the current
+color preference (dark mode or light mode) by the operating system.
+
+The terminal will reply back in either of the two ways:
+
+VT sequence       | description
+------------------|---------------------------------
+`CSI ? 997 ; 1 n` | DSR reply to indicate dark mode
+`CSI ? 997 ; 2 n` | DSR reply to indicate light mode
+
+## Request unsolicited DSR on color palette updates
+
+Send `CSI ? 2031 h` to the terminal to enable unsolicited DSR (device status report) messages
+for color palette updates and `CSI ? 2031 l` respectively to disable it again.
+
+The sent out DSR looks equivalent to the already above mentioned.
+This notification is not just sent when dark/light mode has been changed
+by the operating system / desktop, but also if the user explicitly changed color scheme,
+e.g. by configuration.

metainfo.xml

@@ -126,7 +126,11 @@
           <li>Do not clear search term when entering search editor again.</li>
           <li>Clear search term when switch to insert vi mode (#1135)</li>
           <li>Delete dpi_scale entry in configuration (#1137)</li>
+          <li>Removes the ability to inline colorschemes within a configuration profile. Colorschemes must now always be referenced by their name.</li>
+          <li>Adds the ability to chose a color scheme based on the operating systems's dark/light mode setting. This will change live whenever the OS's dark/light mode setting changes as well (#604).</li>
           <li>Adds VT sequence DECSSCLS (change scroll speed) and properly handle DECSCLM (enable slow scrolling mode) (#1204)</li>
+          <li>Adds VT sequence parameter ?996 to DSR to request a report of current color scheme dark/light mode hint.</li>
+          <li>Adds VT sequence `SM ?2031` and `RM ?2031` to enable/disable unsolicited DSR for color scheme updates by the user or OS.</li>
           <li>Adds percentage value to Indicator Statusline to indicate scroll offset in scrollback buffer.</li>
           <li>Adds inheritance of profiles in configuration file based on default profile (#1063).</li>
           <li>Adds config option `profile.*.bell` to adjust BEL behavior and fixes (#1162) and (#1163).</li>

mkdocs.yml

@@ -107,6 +107,7 @@ nav:
     - vt-extensions/index.md
     - vt-extensions/clickable-links.md
     - vt-extensions/vertical-line-marks.md
+    - vt-extensions/color-palette-update-notifications.md
     - vt-extensions/synchronized-output.md
     - vt-extensions/buffer-capture.md
     - vt-extensions/font-settings.md

src/contour/CMakeLists.txt

@@ -111,7 +111,6 @@ target_compile_definitions(contour PRIVATE
 )
 
 set_target_properties(contour PROPERTIES AUTOMOC ON)
-
 set_target_properties(contour PROPERTIES AUTORCC ON)
 
 # Disable all deprecated Qt functions prior to Qt 6.0

src/contour/Config.cpp

@@ -985,7 +985,6 @@ namespace
     {
         if (!node)
             return;
-        ;
 
         usedKeys.emplace(basePath);
         using vtbackend::RGBColor;
@@ -1159,6 +1158,37 @@ namespace
         return colors;
     }
 
+    vtbackend::ColorPalette loadColorSchemeByName(
+        UsedKeys& usedKeys,
+        string const& path,
+        YAML::Node const& nameNode,
+        unordered_map<string, vtbackend::ColorPalette> const& colorschemes,
+        logstore::message_builder& logger)
+    {
+        auto const name = nameNode.as<string>();
+        if (auto i = colorschemes.find(name); i != colorschemes.end())
+        {
+            usedKeys.emplace(path);
+            return i->second;
+        }
+
+        for (fs::path const& prefix: configHomes("contour"))
+        {
+            auto const filePath = prefix / "colorschemes" / (name + ".yml");
+            auto fileContents = readFile(filePath);
+            if (!fileContents)
+                continue;
+            YAML::Node subDocument = YAML::Load(fileContents.value());
+            UsedKeys usedColorKeys;
+            auto colors = loadColorScheme(usedColorKeys, "", subDocument);
+            // TODO: Check usedColorKeys for validity.
+            configLog()("Loaded colors from {}.", filePath.string());
+            return colors;
+        }
+        logger("Could not open colorscheme file for \"{}\".", name);
+        return vtbackend::ColorPalette {};
+    }
+
     void softLoadFont(UsedKeys& usedKeys,
                       string_view basePath,
                       YAML::Node const& node,
@@ -1301,40 +1331,29 @@ namespace
                                unordered_map<string, vtbackend::ColorPalette> const& colorschemes,
                                logstore::message_builder logger)
     {
-
         if (auto colors = profile["colors"]; colors) // {{{
         {
             usedKeys.emplace(fmt::format("{}.{}.colors", parentPath, profileName));
             auto const path = fmt::format("{}.{}.{}", parentPath, profileName, "colors");
             if (colors.IsMap())
-                terminalProfile.colors = loadColorScheme(usedKeys, path, colors);
-            else if (auto i = colorschemes.find(colors.as<string>()); i != colorschemes.end())
             {
-                usedKeys.emplace(path);
-                terminalProfile.colors = i->second;
+                terminalProfile.colors =
+                    DualColorConfig { .darkMode = loadColorSchemeByName(
+                                          usedKeys, path + ".dark", colors["dark"], colorschemes, logger),
+                                      .lightMode = loadColorSchemeByName(
+                                          usedKeys, path + ".light", colors["light"], colorschemes, logger) };
+#if QT_VERSION < QT_VERSION_CHECK(6, 5, 0)
+                errorLog()("Dual color scheme is not supported by your local Qt version. "
+                           "Falling back to single color scheme.");
+#endif
             }
             else if (colors.IsScalar())
             {
-                bool found = false;
-                for (fs::path const& prefix: configHomes("contour"))
-                {
-                    auto const filePath = prefix / "colorschemes" / (colors.as<string>() + ".yml");
-                    auto fileContents = readFile(filePath);
-                    if (!fileContents)
-                        continue;
-                    YAML::Node subDocument = YAML::Load(fileContents.value());
-                    UsedKeys usedColorKeys;
-                    terminalProfile.colors = loadColorScheme(usedColorKeys, "", subDocument);
-                    // TODO: Check usedColorKeys for validity.
-                    configLog()("Loaded colors from {}.", filePath.string());
-                    found = true;
-                    break;
-                }
-                if (!found)
-                    logger("Could not open colorscheme file for \"{}\".", colors.as<string>());
+                terminalProfile.colors =
+                    SimpleColorConfig { loadColorSchemeByName(usedKeys, path, colors, colorschemes, logger) };
             }
             else
-                logger("scheme '{}' not found.", colors.as<string>());
+                logger("Invalid colors value.");
         }
         else
             logger("No colors section in profile {} found.", profileName);
@@ -1372,12 +1391,18 @@ namespace
                              "size_indicator_on_resize",
                              terminalProfile.sizeIndicatorOnResize,
                              logger);
-        tryLoadChildRelative(usedKeys,
-                             profile,
-                             basePath,
-                             "draw_bold_text_with_bright_colors",
-                             terminalProfile.colors.useBrightColors,
-                             logger);
+        bool useBrightColors = false;
+        tryLoadChildRelative(
+            usedKeys, profile, basePath, "draw_bold_text_with_bright_colors", useBrightColors, logger);
+
+        if (auto* simple = get_if<SimpleColorConfig>(&terminalProfile.colors))
+            simple->colors.useBrightColors = useBrightColors;
+        else if (auto* dual = get_if<DualColorConfig>(&terminalProfile.colors))
+        {
+            dual->darkMode.useBrightColors = useBrightColors;
+            dual->lightMode.useBrightColors = useBrightColors;
+        }
+
         tryLoadChildRelative(usedKeys, profile, basePath, "wm_class", terminalProfile.wmClass, logger);
 
         if (auto args = profile["arguments"]; args && args.IsSequence())
@@ -2026,19 +2051,11 @@ void loadConfigFromFile(Config& config, fs::path const& fileName)
     if (auto colorschemes = doc["color_schemes"]; colorschemes)
     {
         usedKeys.emplace("color_schemes");
-        // load default colorschemes
-        const std::string nameDefault = "default";
-        auto const pathDefault = "color_schemes." + nameDefault;
-        config.colorschemes[nameDefault] =
-            loadColorScheme(usedKeys, pathDefault, colorschemes.begin()->second);
 
         for (auto i = colorschemes.begin(); i != colorschemes.end(); ++i)
         {
             auto const name = i->first.as<string>();
-            if (name == nameDefault)
-                continue;
             auto const path = "color_schemes." + name;
-            config.colorschemes[name] = config.colorschemes[nameDefault];
             updateColorScheme(config.colorschemes[name], usedKeys, path, i->second);
         }
     }

src/contour/Config.h

@@ -132,6 +132,19 @@ struct InputModeConfig
     CursorConfig cursor;
 };
 
+struct DualColorConfig
+{
+    vtbackend::ColorPalette darkMode {};
+    vtbackend::ColorPalette lightMode {};
+};
+
+struct SimpleColorConfig
+{
+    vtbackend::ColorPalette colors {};
+};
+
+using ColorConfig = std::variant<SimpleColorConfig, DualColorConfig>;
+
 struct TerminalProfile
 {
     vtpty::Process::ExecInfo shell;
@@ -168,7 +181,7 @@ struct TerminalProfile
     } permissions;
 
     bool drawBoldTextWithBrightColors = false;
-    vtbackend::ColorPalette colors {};
+    ColorConfig colors = SimpleColorConfig {};
 
     vtbackend::LineCount modalCursorScrollOff { 8 };
 

src/contour/ContourGuiApp.cpp

@@ -12,7 +12,12 @@
 #include <crispy/utils.h>
 
 #include <QtCore/QProcess>
+#if !defined(__APPLE__) && !defined(_WIN32)
+    #include <QtDBus/QDBusConnection>
+#endif
+#include <QtDBus/QtDBus>
 #include <QtGui/QGuiApplication>
+#include <QtGui/QStyleHints>
 #include <QtGui/QSurfaceFormat>
 #include <QtQml/QQmlApplicationEngine>
 #include <QtQml/QQmlContext>
@@ -347,6 +352,25 @@ int ContourGuiApp::terminalGuiAction()
     // NB: We use QApplication over QGuiApplication because we want to use SystemTrayIcon.
     QApplication app(qtArgsCount, (char**) qtArgsPtr.data());
 
+#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
+    _colorPreference = QGuiApplication::styleHints()->colorScheme() == Qt::ColorScheme::Dark
+                           ? vtbackend::ColorPreference::Dark
+                           : vtbackend::ColorPreference::Light;
+
+    displayLog()("Color theme mode at startup: {}", _colorPreference);
+
+    connect(QGuiApplication::styleHints(), &QStyleHints::colorSchemeChanged, [&](Qt::ColorScheme newScheme) {
+        auto const newValue = newScheme == Qt::ColorScheme::Dark ? vtbackend::ColorPreference::Dark
+                                                                 : vtbackend::ColorPreference::Light;
+        if (_colorPreference == newValue)
+            return;
+
+        _colorPreference = newValue;
+        displayLog()("Color preference changed to {} mode\n", _colorPreference);
+        sessionsManager().updateColorPreference(_colorPreference);
+    });
+#endif
+
 #if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
     // Enforce OpenGL over any other. As much as I'd love to provide other backends, too.
     // We currently only support OpenGL.

src/contour/ContourGuiApp.h

@@ -4,16 +4,16 @@
 #include <contour/Config.h>
 #include <contour/ContourApp.h>
 #include <contour/TerminalSessionManager.h>
+#include <contour/helper.h>
 
 #include <vtpty/Process.h>
 
+#include <QtDBus/QDBusVariant>
 #include <QtQml/QQmlApplicationEngine>
 
 #include <filesystem>
-#include <list>
 #include <memory>
 #include <optional>
-#include <string_view>
 
 namespace contour
 {
@@ -55,7 +55,7 @@ class ContourGuiApp: public QObject, public ContourApp
     {
         if (const auto* const profile = config().profile(profileName()))
             return *profile;
-        fmt::print("Failed to access config profile.\n");
+        displayLog()("Failed to access config profile.");
         Require(false);
     }
 
@@ -69,6 +69,8 @@ class ContourGuiApp: public QObject, public ContourApp
 
     [[nodiscard]] static QUrl resolveResource(std::string_view path);
 
+    vtbackend::ColorPreference colorPreference() const noexcept { return _colorPreference; }
+
   private:
     static void ensureTermInfoFile();
     bool loadConfig(std::string const& target);
@@ -82,6 +84,8 @@ class ContourGuiApp: public QObject, public ContourApp
     char const** _argv = nullptr;
     std::optional<vtpty::Process::ExitStatus> _exitStatus;
 
+    vtbackend::ColorPreference _colorPreference = vtbackend::ColorPreference::Dark;
+
     std::unique_ptr<QQmlApplicationEngine> _qmlEngine;
 };