1 files changed, 89 insertions, 0 deletions
diff --git a/qutebrowser/config/configinit.py b/qutebrowser/config/configinit.py
index b15225210..3c80cfe1b 100644
--- a/qutebrowser/config/configinit.py
+++ b/qutebrowser/config/configinit.py
@@ -199,6 +199,90 @@ def qt_args(namespace: argparse.Namespace) -> typing.List[str]:
     return argv
 
 
+def _darkmode_settings() -> typing.Iterator[typing.Tuple[str, str]]:
+    """Get necessary blink settings to configure dark mode for QtWebEngine."""
+    if not config.val.colors.webpage.darkmode.enabled:
+        return
+
+    # Mapping from a colors.webpage.darkmode.algorithm setting value to
+    # Chromium's DarkModeInversionAlgorithm enum values.
+    algorithms = {
+        # 0: kOff (not exposed)
+        # 1: kSimpleInvertForTesting (not exposed)
+        'brightness-rgb': 2,  # kInvertBrightness
+        'lightness-hsl': 3,  # kInvertLightness
+        'lightness-cielab': 4,  # kInvertLightnessLAB
+    }
+
+    # Mapping from a colors.webpage.darkmode.policy.images setting value to
+    # Chromium's DarkModeImagePolicy enum values.
+    image_policies = {
+        'always': 0,  # kFilterAll
+        'never': 1,  # kFilterNone
+        'smart': 2,  # kFilterSmart
+    }
+
+    # Mapping from a colors.webpage.darkmode.policy.page setting value to
+    # Chromium's DarkModePagePolicy enum values.
+    page_policies = {
+        'always': 0,  # kFilterAll
+        'smart': 1,  # kFilterByBackground
+    }
+
+    bools = {
+        True: 'true',
+        False: 'false',
+    }
+
+    _setting_description_type = typing.Tuple[
+        str,  # qutebrowser option name
+        str,  # darkmode setting name
+        # Mapping from the config value to a string (or something convertable
+        # to a string) which gets passed to Chromium.
+        typing.Optional[typing.Mapping[typing.Any, typing.Union[str, int]]],
+    ]
+    if qtutils.version_check('5.15', compiled=False):
+        settings = [
+            ('enabled', 'Enabled', bools),
+            ('algorithm', 'InversionAlgorithm', algorithms),
+        ]  # type: typing.List[_setting_description_type]
+        mandatory_setting = 'enabled'
+    else:
+        settings = [
+            ('algorithm', '', algorithms),
+        ]
+        mandatory_setting = 'algorithm'
+
+    settings += [
+        ('contrast', 'Contrast', None),
+        ('policy.images', 'ImagePolicy', image_policies),
+        ('policy.page', 'PagePolicy', page_policies),
+        ('threshold.text', 'TextBrightnessThreshold', None),
+        ('threshold.background', 'BackgroundBrightnessThreshold', None),
+        ('grayscale.all', 'Grayscale', bools),
+        ('grayscale.images', 'ImageGrayscale', None),
+    ]
+
+    for setting, key, mapping in settings:
+        # To avoid blowing up the commandline length, we only pass modified
+        # settings to Chromium, as our defaults line up with Chromium's.
+        # However, we always pass enabled/algorithm to make sure dark mode gets
+        # actually turned on.
+        value = config.instance.get(
+            'colors.webpage.darkmode.' + setting,
+            fallback=setting == mandatory_setting)
+        if isinstance(value, usertypes.Unset):
+            continue
+
+        if mapping is not None:
+            value = mapping[value]
+
+        # FIXME: This is "forceDarkMode" starting with Chromium 83
+        prefix = 'darkMode'
+
+        yield prefix + key, str(value)
+
+
 def _qtwebengine_args(namespace: argparse.Namespace) -> typing.Iterator[str]:
     """Get the QtWebEngine arguments to use based on the config."""
     if not qtutils.version_check('5.11', compiled=False):
@@ -224,6 +308,11 @@ def _qtwebengine_args(namespace: argparse.Namespace) -> typing.Iterator[str]:
         yield '--enable-logging'
         yield '--v=1'
 
+    blink_settings = list(_darkmode_settings())
+    if blink_settings:
+        yield '--blink-settings=' + ','.join('{}={}'.format(k, v)
+                                             for k, v in blink_settings)
+
     settings = {
         'qt.force_software_rendering': {
             'software-opengl': None,