Implementation of the selection in the text node

src/ftxui/dom/text.cpp

@@ -42,6 +42,15 @@ class Text : public Node {
         continue;
       }
       screen.PixelAt(x, y).character = cell;
+
+      if(screen.PixelAt(x, y).selectable == true)
+      {
+        if(screen.selection_region.Contain(x, y)) {
+          screen.PixelAt(x, y).inverted ^= true;
+          screen.selection_text += screen.PixelAt(x, y).character;
+        }
+      }
+
       ++x;
     }
   }