add 150 class map and divergent map

include/spark_dsg/colormaps.h

@@ -42,9 +42,9 @@ namespace spark_dsg::colormaps {
 
 /**
  * @brief Generate a gray-scale color.
- * @param value The value of the gray [0,1, where 0 is black and 1 is white].
+ * @param value The value of the gray [0,1], where 0 is black and 1 is white.
  */
-Color gray(float value = 0.5f);
+Color gray(float value);
 
 /**
  * @brief Generate a color based on a quality value.
@@ -92,6 +92,18 @@ Color ironbow(float value);
  */
 Color rainbow(float value);
 
+/**
+ * @brief Generate a color from a general divergent colormap
+ * @param value A value in [0, 1]. 0 results in one color, 1 in the other, and 0.5 in a
+ * neutral color
+ */
+Color divergent(float value,
+                float hue_low = 0.66,
+                float hue_high = 0.0,
+                float saturation = 0.9,
+                float luminance = 0.9,
+                bool dark = true);
+
 /**
  * @brief Generate a sequence of never repeating colors in the rainbow spectrum.
  * @param id The id of the color in the sequence.
@@ -107,4 +119,10 @@ Color rainbowId(size_t id, size_t ids_per_revolution = 16);
  */
 Color colorbrewer(size_t id);
 
+/**
+ * @brief Pick a color from a custom palette from distinctipy with 150 colors
+ * @param id The id to pick from the sequence
+ */
+Color distrinct_150(size_t id);
+
 }  // namespace spark_dsg::colormaps

src/colormaps.cpp

@@ -56,6 +56,39 @@ static const std::vector<Color> colorbrewer_palette{
     {177, 89, 40},
 };
 
+static const std::vector<Color> custom_150_palette{
+    {0, 102, 51},    {0, 255, 0},     {4, 74, 246},    {191, 191, 181}, {72, 90, 13},
+    {204, 0, 102},   {196, 26, 252},  {254, 217, 251}, {127, 255, 255}, {133, 87, 54},
+    {130, 26, 50},   {10, 5, 65},     {3, 75, 135},    {18, 124, 89},   {21, 182, 126},
+    {90, 171, 130},  {189, 217, 119}, {188, 63, 11},   {86, 82, 249},   {196, 221, 253},
+    {187, 78, 62},   {188, 49, 167},  {182, 161, 248}, {112, 201, 196}, {11, 41, 99},
+    {211, 102, 1},   {4, 227, 101},   {147, 201, 250}, {255, 0, 0},     {224, 33, 3},
+    {254, 74, 17},   {255, 127, 0},   {176, 188, 66},  {247, 29, 54},   {74, 117, 80},
+    {71, 56, 199},   {250, 107, 216}, {4, 204, 229},   {25, 208, 53},   {52, 249, 65},
+    {70, 220, 121},  {68, 86, 156},   {7, 150, 36},    {255, 127, 127}, {64, 46, 6},
+    {139, 167, 123}, {18, 165, 78},   {157, 166, 28},  {9, 163, 248},   {191, 67, 218},
+    {135, 243, 61},  {81, 119, 190},  {0, 126, 204},   {228, 73, 252},  {227, 108, 163},
+    {127, 255, 127}, {50, 211, 203},  {3, 190, 177},   {127, 255, 0},   {11, 59, 10},
+    {108, 38, 143},  {243, 33, 254},  {182, 106, 251}, {120, 251, 191}, {145, 115, 208},
+    {48, 129, 250},  {43, 78, 65},    {73, 0, 197},    {0, 249, 143},   {80, 160, 69},
+    {200, 252, 62},  {127, 39, 198},  {139, 79, 186},  {155, 225, 169}, {239, 148, 63},
+    {30, 183, 5},    {137, 90, 3},    {49, 35, 155},   {242, 186, 113}, {127, 0, 0},
+    {191, 148, 1},   {134, 147, 65},  {175, 254, 104}, {84, 183, 23},   {12, 87, 183},
+    {1, 20, 178},    {185, 224, 0},   {255, 255, 127}, {44, 252, 176},  {62, 186, 252},
+    {3, 253, 46},    {41, 208, 156},  {138, 94, 126},  {32, 31, 231},   {192, 120, 193},
+    {231, 66, 87},   {105, 0, 153},   {251, 216, 190}, {228, 45, 198},  {0, 0, 255},
+    {67, 234, 247},  {156, 4, 152},   {253, 219, 57},  {183, 148, 126}, {246, 154, 179},
+    {127, 127, 255}, {0, 255, 255},   {225, 189, 224}, {47, 253, 125},  {47, 0, 127},
+    {92, 207, 58},   {173, 253, 235}, {251, 78, 170},  {164, 41, 91},   {0, 127, 0},
+    {65, 43, 54},    {196, 100, 129}, {143, 157, 184}, {234, 190, 2},   {0, 234, 191},
+    {191, 254, 179}, {149, 1, 215},   {67, 231, 11},   {131, 195, 0},   {188, 121, 62},
+    {70, 143, 13},   {106, 168, 230}, {231, 106, 88},  {255, 255, 0},   {121, 54, 15},
+    {127, 255, 0},   {248, 157, 252}, {63, 7, 14},     {146, 63, 249},  {185, 8, 32},
+    {247, 0, 223},   {234, 252, 199}, {91, 29, 248},   {122, 0, 89},    {41, 99, 220},
+    {28, 132, 140},  {127, 209, 111}, {110, 54, 79},   {63, 68, 107},   {214, 0, 171},
+    {71, 9, 82},     {224, 187, 57},  {253, 20, 130},  {127, 127, 0},   {113, 132, 132},
+};
+
 Color gray(float value) {
   const auto char_value = fromUnitRange(std::clamp(value, 0.0f, 1.0f));
   return Color(char_value, char_value, char_value);
@@ -114,6 +147,19 @@ Color rainbow(float value) {
   return Color::fromHLS(std::clamp(value, 0.0f, 1.0f), 0.5f, 1.0f);
 }
 
+Color divergent(float value,
+                float hue_low,
+                float hue_high,
+                float saturation,
+                float luminance,
+                bool dark) {
+  value = std::clamp(value, 0.0f, 1.0f);
+  const float alpha = value > 0.5f ? 2.0f * (value - 0.5f) : 2.0f * (0.5f - value);
+  return Color::fromHLS(value > 0.5f ? hue_high : hue_low,
+                        dark ? alpha * luminance : (alpha * luminance) + 1.0f - alpha,
+                        alpha * saturation);
+}
+
 Color rainbowId(size_t id, size_t ids_per_revolution) {
   return rainbow(exponentialOffsetId(id, ids_per_revolution));
 }

tests/utest_color.cpp

@@ -168,4 +168,22 @@ TEST(Color, RainbowID) {
   EXPECT_EQ(colormaps::rainbowId(33, 16), Color(255, 120, 0));
 }
 
+TEST(Color, Divergent) {
+  const auto dark_cmap = [](float value) {
+    return colormaps::divergent(value, 0.0f, 2.0f / 3.0f, 1.0f, 0.5f, true);
+  };
+
+  EXPECT_EQ(dark_cmap(0.0f), Color::red());
+  EXPECT_EQ(dark_cmap(0.5f), Color::black());
+  EXPECT_EQ(dark_cmap(1.0f), Color::blue());
+
+  const auto light_cmap = [](float value) {
+    return colormaps::divergent(value, 0.0f, 2.0f / 3.0f, 1.0f, 0.5f, false);
+  };
+
+  EXPECT_EQ(light_cmap(0.0f), Color::red());
+  EXPECT_EQ(light_cmap(0.5f), Color::white());
+  EXPECT_EQ(light_cmap(1.0f), Color::blue());
+}
+
 }  // namespace spark_dsg