Refact road colour generation script

roads.mss

@@ -1,10 +1,10 @@
 /* For the main linear features, such as roads and railways. */
 
 //road colors for major roads were generated with scripts/generate_road_colors.py
-@motorway-fill: #e892a2; // lch(70, 35, 10) Conversion error on moving from lch to rgb: 0.5 lch(-0.3, -0.5, -0.9)
-@trunk-fill: #f9b29c; // lch(79, 33, 42) Conversion error on moving from lch to rgb: 0.8 lch(-0.4, -1.5, 1.1)
-@primary-fill: #fcd6a4; // lch(88, 31, 74) Conversion error on moving from lch to rgb: 1.8 lch(-0.3, -0.8, 4.0)
-@secondary-fill: #f7fabf; // lch(97, 29, 106) Conversion error on moving from lch to rgb: 1.8 lch(-0.2, 0.7, 4.4)
+@motorway-fill: #e892a2; // Lch(70,35,10), error 0.5
+@trunk-fill: #f9b29c; // Lch(79,33,42), error 0.7
+@primary-fill: #fcd6a4; // Lch(88,31,74), error 1.7
+@secondary-fill: #f7fabf; // Lch(97,29,106), error 1.7
 @tertiary-fill: #ffffff;
 @residential-fill: #ffffff;
 @service-fill: @residential-fill;
@@ -23,15 +23,16 @@
 @taxiway-fill: @aeroway-fill;
 @helipad-fill: @aeroway-fill;
 
-@motorway-low-zoom: #e66e89; // lch(62, 50, 10) Conversion error on moving from lch to rgb: 0.6 lch(-0.4, -0.4, -1.1)
-@trunk-low-zoom: #fa9476; // lch(72, 50, 42) Conversion error on moving from lch to rgb: 0.8 lch(-0.5, -1.9, 0.7)
-@primary-low-zoom: #f8c171; // lch(82, 50, 74) Conversion error on moving from lch to rgb: 2.1 lch(-0.5, -1.1, 3.4)
+@motorway-low-zoom: #e66e89; // Lch(62,50,10), error 0.7
+@trunk-low-zoom: #fa9476; // Lch(72,50,42), error 0.8
+@primary-low-zoom: #f8c171; // Lch(82,50,74), error 2.1
+@secondary-low-zoom: #e6ef89; // Lch(92,50,106), error 2.2
 
 @default-casing: white;
-@motorway-casing: #dc2a67; // lch(50, 70, 10) Conversion error on moving from lch to rgb: 1.0 lch(-0.7, -0.1, -1.2)
-@trunk-casing: #c84e2f; // lch(50, 65, 42) Conversion error on moving from lch to rgb: 0.8 lch(-0.7, -1.8, 0.0)
-@primary-casing: #a06b00; // lch(50, 60, 74) Conversion error on moving from lch to rgb: 1.6 lch(-0.4, -1.7, 2.2)
-@secondary-casing: #707d05; // lch(50, 55, 106) Conversion error on moving from lch to rgb: 1.9 lch(-0.2, 1.7, 3.2)
+@motorway-casing: #dc2a67; // Lch(50,70,10), error 1.1
+@trunk-casing: #c84e2f; // Lch(50,65,42), error 0.7
+@primary-casing: #a06b00; // Lch(50,60,74), error 1.6
+@secondary-casing: #707d05; // Lch(50,55,106), error 1.9
 @tertiary-casing: #8f8f8f;
 @residential-casing: #bbb;
 @road-casing: @residential-casing;
@@ -45,10 +46,10 @@
 @bridleway-casing: @default-casing;
 @track-casing: @default-casing;
 
-@motorway-low-zoom-casing: #d63668; // lch(50, 65, 10) Conversion error on moving from lch to rgb: 0.9 lch(-0.6, -0.2, -1.2)
-@trunk-low-zoom-casing: #d76444; // lch(56.7, 60, 42) Conversion error on moving from lch to rgb: 0.8 lch(-0.6, -1.9, 0.3)
-@primary-low-zoom-casing: #c48e37; // lch(63.3, 55, 74) Conversion error on moving from lch to rgb: 2.0 lch(-0.5, -1.0, 2.9)
-@secondary-low-zoom-casing: #a8b14f; // lch(70, 50, 106) Conversion error on moving from lch to rgb: 2.1 lch(-0.3, 1.4, 3.7)
+@motorway-low-zoom-casing: #c24e6b; // Lch(50,50,10), error 0.8
+@trunk-low-zoom-casing: #cf6649; // Lch(56,55,42), error 0.9
+@primary-low-zoom-casing: #c38a27; // Lch(62,60,74), error 2.1
+@secondary-low-zoom-casing: #9eae23; // Lch(68,65,106), error 2.3
 
 @unimportant-road: @residential-casing;
 

scripts/create_standard_shields

@@ -25,11 +25,12 @@ primary:#d5b284
 secondary:#c6ca90
 tertiary:#c6c6c6'
 
-#motorway: lch(65, 30, 10) Conversion error on moving from lch to rgb: 0.4 lch(-0.3, -0.4, -0.9)
-#trunk: lch(70, 30, 42) Conversion error on moving from lch to rgb: 0.8 lch(-0.3, -1.4, 1.1)
-#primary: lch(75, 30, 74) Conversion error on moving from lch to rgb: 1.7 lch(-0.3, -0.8, 3.9)
-#secondary: lch(80, 30, 106) Conversion error on moving from lch to rgb: 1.7 lch(-0.2, 0.7, 4.3)
-#tertiary: lch(80, 0, 0) Conversion error on moving from lch to rgb: 0.0 lch(-0.0, 0.0, 322.5)
+# motorway: Lch(65,30,10), error 0.5
+# trunk: Lch(70,30,42), error 0.7
+# primary: Lch(75,30,74), error 1.6
+# secondary: Lch(80,30,106), error 1.8
+# tertiary: Lch(80,0,0), error 0.1
+
 
 
 

scripts/generate_road_colours.py

@@ -0,0 +1,94 @@
+from colormath.color_conversions import convert_color
+from colormath.color_objects import LabColor, LCHabColor, sRGBColor
+from colormath.color_diff import delta_e_cie2000
+import numpy
+
+from collections import OrderedDict, namedtuple
+
+class Color:
+  def __init__(self, lch_tuple):
+    self.m_lch = LCHabColor(*lch_tuple)
+
+  def lch(self):
+    return "Lch({:.0f},{:.0f},{:.0f})".format(*(self.m_lch.get_value_tuple()))
+
+  def rgb(self):
+    rgb = convert_color(self.m_lch, sRGBColor)
+    if (rgb.rgb_r != rgb.clamped_rgb_r or rgb.rgb_g != rgb.clamped_rgb_g or rgb.rgb_b != rgb.clamped_rgb_b):
+      raise Exception("Colour {} is outside sRGB".format(self.lch()))
+    return rgb.get_rgb_hex()
+
+  def rgb_error(self):
+    return delta_e_cie2000(convert_color(self.m_lch, LabColor),
+                           convert_color(sRGBColor.new_from_rgb_hex(self.rgb()), LabColor))
+
+road_classes = ["motorway", "trunk", "primary", "secondary"]
+colour_divisions = len(road_classes) - 1
+hues = OrderedDict()
+
+# The minimum and maximum hue for the road colours
+# Because hue is a circle, it may be needed to add/subtract 360 to the min or
+# max when changing them
+
+min_h = 10
+max_h = 106
+delta_h = (max_h - min_h) / colour_divisions
+
+h = min_h
+for name in road_classes:
+  hues[name] = h
+  h = (h + delta_h) % 360
+
+print hues
+# A class to hold information for each line
+ColourInfo = namedtuple("ColourInfo", ["start_l", "end_l", "start_c", "end_c"])
+
+line_colour_infos = OrderedDict()
+
+# The saturation and lightness for each type of line
+line_colour_infos["fill"] = ColourInfo(start_l = 70, end_l = 97, start_c = 35, end_c = 29)
+line_colour_infos["low-zoom"] = ColourInfo(start_l = 62, end_l = 92, start_c = 50, end_c = 50)
+
+line_colour_infos["casing"] = ColourInfo(start_l = 50, end_l = 50, start_c = 70, end_c = 55)
+line_colour_infos["low-zoom-casing"] = ColourInfo(start_l = 50, end_l = 70, start_c = 50, end_c = 65)
+
+# Colours for the MSS
+colours = OrderedDict()
+
+for line_name, line_colour_info in line_colour_infos.iteritems():
+  c = line_colour_info.start_c
+  delta_c = (line_colour_info.end_c - line_colour_info.start_c) / colour_divisions
+  l = line_colour_info.start_l
+  delta_l = (line_colour_info.end_l - line_colour_info.start_l) / colour_divisions
+
+  for name in road_classes:
+    colours[name + "-" + line_name] = Color((l, c, hues[name]))
+    c += delta_c
+    l += delta_l
+
+for name, colour in colours.iteritems():
+  print "@{name}: {rgb}; // {lch}, error {delta:.1f}".format(name = name, rgb = colour.rgb(), lch = colour.lch(), delta = colour.rgb_error())
+
+# Generate colours for the shields
+shield_colour_info = ColourInfo(start_l = 65, end_l = 80, start_c = 30, end_c = 30)
+shield_colours = OrderedDict()
+
+
+c = shield_colour_info.start_c
+delta_c = (shield_colour_info.end_c - shield_colour_info.start_c) / colour_divisions
+l = shield_colour_info.start_l
+delta_l = (shield_colour_info.end_l - shield_colour_info.start_l) / colour_divisions
+
+for name in road_classes:
+  shield_colours[name] = Color((l, c, hues[name]))
+  c += delta_c
+  l += delta_l
+
+shield_colours["tertiary"] = Color((shield_colour_info.end_l, 0, 0))
+
+print "\n\nRoad shield information\n\n"
+for name, colour in shield_colours.iteritems():
+  print "{name}:{rgb}".format(name = name, rgb = colour.rgb())
+
+for name, colour in shield_colours.iteritems():
+  print "# {name}: {lch}, error {delta:.1f}".format(name = name, lch = colour.lch(), delta = colour.rgb_error())