Support multiple kind of cursor shapes. (#505)

https://github.com/ArthurSonzogni/FTXUI/issues/424

include/ftxui/dom/elements.hpp

@@ -126,9 +126,6 @@ enum Direction { WIDTH, HEIGHT };
 enum Constraint { LESS_THAN, EQUAL, GREATER_THAN };
 Decorator size(Direction, Constraint, int value);
 
-// --
-Decorator reflect(Box& box);
-
 // --- Frame ---
 // A frame is a scrollable area. The internal area is potentially larger than
 // the external one. The internal area is scrolled in order to make visible the
@@ -139,7 +136,21 @@ Element yframe(Element);
 Element focus(Element);
 Element select(Element);
 
+// --- Cursor ---
+// Those are similar to `focus`, but also change the shape of the cursor.
+Element focusCursorBlock(Element);
+Element focusCursorBlockBlinking(Element);
+Element focusCursorBar(Element);
+Element focusCursorBarBlinking(Element);
+Element focusCursorUnderline(Element);
+Element focusCursorUnderlineBlinking(Element);
+
+// --- Misc ---
 Element vscroll_indicator(Element);
+Decorator reflect(Box& box);
+// Before drawing the |element| clear the pixel below. This is useful in
+// combinaison with dbox.
+Element clear_under(Element element);
 
 // --- Util --------------------------------------------------------------------
 Element hcenter(Element);
@@ -148,10 +159,6 @@ Element center(Element);
 Element align_right(Element);
 Element nothing(Element element);
 
-// Before drawing the |element| clear the pixel below. This is useful in
-// combinaison with dbox.
-Element clear_under(Element element);
-
 namespace Dimension {
 Dimensions Fit(Element&);
 }  // namespace Dimension

include/ftxui/screen/screen.hpp

@@ -80,6 +80,17 @@ class Screen {
   struct Cursor {
     int x = 0;
     int y = 0;
+
+    enum Shape {
+      Hidden = 0,
+      BlockBlinking = 1,
+      Block = 2,
+      UnderlineBlinking = 3,
+      Underline = 4,
+      Bar = 5,
+      BarBlinking = 6,
+    };
+    Shape shape;
   };
   Cursor cursor() const { return cursor_; }
   void SetCursor(Cursor cursor) { cursor_ = cursor; }
@@ -91,8 +102,6 @@ class Screen {
   int dimy_;
   std::vector<std::vector<Pixel>> pixels_;
   Cursor cursor_;
-
- private:
 };
 
 }  // namespace ftxui