feat: Portal color generator

app/helpers/color_helper.rb

@@ -0,0 +1,93 @@
+module ColorHelper
+  def hex_to_rgb(hex_color)
+    # Remove the '#' character if it's there
+    hex_color = hex_color.tr('#', '')
+
+    # Split the hex color string into the RGB components
+    r = hex_color[0..1].to_i(16)
+    g = hex_color[2..3].to_i(16)
+    b = hex_color[4..5].to_i(16)
+
+    [r, g, b]
+  end
+
+  def rgb_to_hex(red, green, blue)
+    hex = [red, green, blue].map do |color|
+      color = 255 if color > 255
+      color = 0 if color.negative?
+
+      color.round.to_s(16).rjust(2, '0')
+    end.join.upcase
+
+    "##{hex}".downcase
+  end
+
+  def get_luminance(color)
+    return 0 if color == 'transparent'
+
+    r, g, b = hex_to_rgb(color)
+    (0.2126 * channel_to_luminance(r)) + (0.7152 * channel_to_luminance(g)) + (0.0722 * channel_to_luminance(b))
+  end
+
+  def get_contrast(color1, color2)
+    luminance1 = get_luminance(color1)
+    luminance2 = get_luminance(color2)
+
+    if luminance1 > luminance2
+      (luminance1 + 0.05) / (luminance2 + 0.05)
+    else
+      (luminance2 + 0.05) / (luminance1 + 0.05)
+    end
+  end
+
+  def mix(color1, color2, weight)
+    # Parse colors and normalize
+    r1, g1, b1 = hex_to_rgb(color1).map { |c| c / 255.0 }
+    r2, g2, b2 = hex_to_rgb(color2).map { |c| c / 255.0 }
+
+    # Mixing algorithm from Sass implementation
+    weight1, weight2 = get_weight_for_mixing(weight)
+
+    # Calculate final color values
+    r = ((r1 * weight1) + (r2 * weight2)) * 255
+    g = ((g1 * weight1) + (g2 * weight2)) * 255
+    b = ((b1 * weight1) + (b2 * weight2)) * 255
+
+    # Convert final values to a CSS RGBA color string
+    rgb_to_hex(r, g, b)
+  end
+
+  def adjust_color_for_contrast(color, background_color, target_ratio = 3.1)
+    max_iterations = 20
+    adjusted_color = color
+
+    max_iterations.times do
+      current_ratio = get_contrast(adjusted_color, background_color)
+      break if current_ratio >= target_ratio
+
+      adjustment_direction = get_luminance(adjusted_color) < 0.5 ? '#ffffff' : '#151718'
+      adjusted_color = mix(adjusted_color, adjustment_direction, 0.05)
+    end
+
+    adjusted_color
+  end
+
+  private
+
+  def get_weight_for_mixing(weight)
+    normalized_weight = (weight * 2) - 1
+    weight2 = (normalized_weight + 1) / 2
+    weight1 = 1 - weight2
+
+    [weight1, weight2]
+  end
+
+  def channel_to_luminance(channel)
+    channel /= 255.0
+    if channel <= 0.03928
+      channel / 12.92
+    else
+      ((channel + 0.055) / 1.055)**2.4
+    end
+  end
+end