1 files changed, 37 insertions, 0 deletions
diff --git a/src/Witness_complex/example/color-picker.cpp b/src/Witness_complex/example/color-picker.cpp
new file mode 100644
index 00000000..fcea033e
--- /dev/null
+++ b/src/Witness_complex/example/color-picker.cpp
@@ -0,0 +1,37 @@
+#include <iostream>
+#include <assert.h>
+
+struct Color {
+  double r, g, b;
+  Color() : r(0), g(0), b(0) { }
+  Color(double r_, double g_, double b_)
+    : r(r_), g(g_), b(b_) { } 
+};
+
+// Convert a double in [0,1] to a color
+template< typename ColorType >
+void double_to_color(double t, ColorType & color) {
+  assert(t >= 0 && t <= 1);
+  double s = 1.0/6;
+  if (t >= 0 && t <= s)
+    color = ColorType(1, 6*t, 0);
+  else if (t > s && t <= 2*s)
+    color = ColorType(1-6*(t-s), 1, 0);
+  else if (t > 2*s && t <= 3*s)
+    color = ColorType(0, 1, 6*(t-2*s));
+  else if (t > 3*s && t <= 4*s)
+    color = ColorType(0, 1-6*(t-3*s), 1);
+  else if (t > 4*s && t <= 5*s)
+    color = ColorType(6*(t-4*s), 0, 1);
+  else
+    color = ColorType(1, 0, 1-6*(t-5*s));
+}
+
+int main (int argc, char * const argv[]) {
+  double number_to_convert = 0;
+  std::cout << "Enter a real number in [0,1]: ";
+  std::cin >> number_to_convert;
+  Color color;
+  double_to_color(number_to_convert, color);
+  std::cout << "The corresponding color in rgb is: (" << color.r << ", " << color.g << ", " << color.b << ")\n";
+}