Add colors.

+ example.

ftxui/include/ftxui/color.hpp

@@ -0,0 +1,40 @@
+#ifndef FTXUI_COLOR_H_
+#define FTXUI_COLOR_H_
+
+#include <cstdint>
+
+namespace ftxui {
+
+enum class Color : uint8_t {
+  // --- Transparent -----
+  Default = 39,
+
+  // --- Grayscale -----
+  Black = 30,
+  GrayDark = 90,
+  GrayLight = 37,
+  White = 97,
+
+  // --- Hue -----
+  Blue = 34,
+  BlueLight = 94,
+
+  Cyan = 36,
+  CyanLight = 96,
+
+  Green = 32,
+  GreenLight = 92,
+
+  Magenta = 35,
+  MagentaLight = 95,
+
+  Red = 31,
+  RedLight = 91,
+
+  Yellow = 33,
+  YellowLight = 93,
+};
+
+};  // namespace ftxui
+
+#endif /* end of include guard: FTXUI_COLOR_H_ */

ftxui/include/ftxui/dom/elements.hpp

@@ -1,6 +1,7 @@
 #ifndef FTXUI_DOM_ELEMENTS_HPP
 #define FTXUI_DOM_ELEMENTS_HPP
 
+#include "ftxui/color.hpp"
 #include "ftxui/dom/node.hpp"
 
 namespace ftxui {
@@ -27,6 +28,8 @@ Element bold(Element);
 Element dim(Element);
 Element inverted(Element);
 Element underlined(Element);
+Element color(Color, Element);
+Element bgcolor(Color, Element);
 
 // --- Decorator ---
 Element hcenter(Element);

ftxui/include/ftxui/screen.hpp

@@ -5,6 +5,8 @@
 #include <vector>
 #include <memory>
 
+#include <ftxui/color.hpp>
+
 namespace ftxui {
 namespace dom {
   class Node;
@@ -16,6 +18,8 @@ struct Pixel {
   bool inverted = false;
   bool underlined = false;
   bool dim = false;
+  Color background_color = Color::Default;
+  Color foreground_color = Color::Default;
 };
 
 class Screen {