Add none value for colors -> tabs.indicator.system.

CHANGELOG.asciidoc

@@ -41,6 +41,8 @@ Added
     * `completion -> scrollbar-padding`
     * `colors -> completion.scrollbar.fg`
     * `colors -> completion.scrollbar.bg`
+- New value `none` for `colors -> tabs.indicator.system` to not display a
+  gradient for tab indicators.
 
 Changed
 ~~~~~~~

qutebrowser/config/configtypes.py

@@ -644,12 +644,14 @@ class ColorSystem(MappingType):
     special = True
     valid_values = ValidValues(('rgb', "Interpolate in the RGB color system."),
                                ('hsv', "Interpolate in the HSV color system."),
-                               ('hsl', "Interpolate in the HSL color system."))
+                               ('hsl', "Interpolate in the HSL color system."),
+                               ('none', "Don't show a gradient."))
 
     MAPPING = {
         'rgb': QColor.Rgb,
         'hsv': QColor.Hsv,
         'hsl': QColor.Hsl,
+        'none': None,
     }
 
 

qutebrowser/utils/utils.py

@@ -164,12 +164,20 @@ def interpolate_color(start, end, percent, colorspace=QColor.Rgb):
         percent: Which value to get (0 - 100)
         colorspace: The desired interpolation color system,
                     QColor::{Rgb,Hsv,Hsl} (from QColor::Spec enum)
+                    If None, start is used except when percent is 100.
 
     Return:
         The interpolated QColor, with the same spec as the given start color.
     """
     qtutils.ensure_valid(start)
     qtutils.ensure_valid(end)
+
+    if colorspace is None:
+        if percent == 100:
+            return end
+        else:
+            return start
+
     out = QColor()
     if colorspace == QColor.Rgb:
         a_c1, a_c2, a_c3, _alpha = start.getRgb()

tests/unit/config/test_configtypes.py

@@ -844,6 +844,8 @@ class TestColorSystem:
         'hsv': QColor.Hsv,
         'HSL': QColor.Hsl,
         'hsl': QColor.Hsl,
+        'none': None,
+        'None': None,
         '': None,
     }
     INVALID = ['RRGB', 'HSV ', '']  # '' is invalid with none_ok=False

tests/unit/utils/test_utils.py

@@ -338,6 +338,17 @@ class TestInterpolateColor:
         expected.setHsl(0, 30, 150)
         assert Color(color) == expected
 
+    @pytest.mark.parametrize('percentage, expected', [
+        (0, (0, 0, 0)),
+        (99, (0, 0, 0)),
+        (100, (255, 255, 255)),
+    ])
+    def test_interpolation_none(self, percentage, expected):
+        """Test an interpolation with a gradient turned off."""
+        color = utils.interpolate_color(Color(0, 0, 0), Color(255, 255, 255),
+                                        percentage, None)
+        assert Color(color) == Color(*expected)
+
 
 @pytest.mark.parametrize('seconds, out', [
     (-1, '-0:01'),