Merge pull request openSUSE#16641 from danidoni/move-color-helpers-to…

…-its-own-file

Move color helpers to its own file

src/api/app/helpers/webui/color_helper.rb

@@ -0,0 +1,22 @@
+module Webui::ColorHelper
+  # Calculates a text color that will contrast well with the given color
+  def contrast_text(color)
+    red_component = color[1..2].to_i(16)
+    green_component = color[3..4].to_i(16)
+    blue_component = color[5..6].to_i(16)
+
+    red = relative_luminance(red_component / 255.0)
+    green = relative_luminance(green_component / 255.0)
+    blue = relative_luminance(blue_component / 255.0)
+
+    # https://www.w3.org/TR/WCAG20/#contrast-ratiodef
+    ((0.2126 * red) + (0.7152 * green) + (0.0722 * blue)) > 0.179 ? 'black' : 'white'
+  end
+
+  # https://www.w3.org/TR/WCAG20/#relativeluminancedef
+  def relative_luminance(color)
+    return color / 12.92 if color <= 0.03928
+
+    ((color + 0.055) / 1.055)**2.4
+  end
+end

src/api/app/helpers/webui/webui_helper.rb

@@ -342,28 +342,6 @@ def contact_link
     url = ::Configuration.contact_url || "mailto:#{::Configuration.admin_email}"
     link_to(name, url)
   end
-
-  # Calculates a text color that will contrast well with the given color
-  def contrast_text(color)
-    blue_component = color % 0x100
-    color_without_blue = ((color - blue_component) / 0x100)
-    green_component = color_without_blue % 0x100
-    red_component = ((color_without_blue - green_component) / 0x100)
-
-    red = relative_luminance(red_component / 255.0)
-    green = relative_luminance(green_component / 255.0)
-    blue = relative_luminance(blue_component / 255.0)
-
-    # https://www.w3.org/TR/WCAG20/#contrast-ratiodef
-    ((0.2126 * red) + (0.7152 * green) + (0.0722 * blue)) > 0.179 ? 'black' : 'white'
-  end
-
-  # https://www.w3.org/TR/WCAG20/#relativeluminancedef
-  def relative_luminance(color)
-    return color / 12.92 if color <= 0.03928
-
-    ((color + 0.055) / 1.055)**2.4
-  end
 end
 
 # rubocop:enable Metrics/ModuleLength

src/api/spec/helpers/webui/color_helper_spec.rb

@@ -0,0 +1,15 @@
+RSpec.describe Webui::ColorHelper do
+  describe '#contrast_text' do
+    context 'when passing a light color' do
+      it 'returns a black text' do
+        expect(contrast_text('#ffffff')).to eql('black')
+      end
+    end
+
+    context 'when passing a dark color' do
+      it 'returns a white text' do
+        expect(contrast_text('#000000')).to eql('white')
+      end
+    end
+  end
+end