Animation (#355)

src/ftxui/dom/separator.cpp

@@ -1,10 +1,11 @@
-#include <memory>  // for make_shared
+#include <memory>  // for make_shared, allocator
 #include <string>  // for string
 
-#include "ftxui/dom/elements.hpp"     // for Element, separator
-#include "ftxui/dom/node.hpp"         // for Node
+#include "ftxui/dom/elements.hpp"  // for Element, BorderStyle, LIGHT, separator, DOUBLE, EMPTY, HEAVY, separatorCharacter, separatorDouble, separatorEmpty, separatorHSelector, separatorHeavy, separatorLight, separatorStyled, separatorVSelector
+#include "ftxui/dom/node.hpp"      // for Node
 #include "ftxui/dom/requirement.hpp"  // for Requirement
 #include "ftxui/screen/box.hpp"       // for Box
+#include "ftxui/screen/color.hpp"     // for Color
 #include "ftxui/screen/screen.hpp"    // for Pixel, Screen
 
 namespace ftxui {
@@ -369,6 +370,142 @@ Element separator(Pixel pixel) {
   return std::make_shared<SeparatorWithPixel>(pixel);
 }
 
+/// @brief Draw an horizontal bar, with the area in between left/right colored
+/// differently.
+/// @param left the left limit of the active area.
+/// @param right the right limit of the active area.
+/// @param selected_color the color of the selected area.
+/// @param unselected_color the color of the unselected area.
+///
+/// ### Example
+///
+/// ```cpp
+/// Element document = separatorHSelector(2,5, Color::White, Color::Blue);
+/// ```
+Element separatorHSelector(float left,
+                           float right,
+                           Color selected_color,
+                           Color unselected_color) {
+  class Impl : public Node {
+   public:
+    Impl(float left, float right, Color selected_color, Color unselected_color)
+        : left_(left),
+          right_(right),
+          selected_color_(selected_color),
+          unselected_color_(unselected_color) {}
+    void ComputeRequirement() override {
+      requirement_.min_x = 1;
+      requirement_.min_y = 1;
+    }
+
+    void Render(Screen& screen) override {
+      if (box_.y_max < box_.y_min)
+        return;
+
+      // This are the two location with an empty demi-cell.
+      int demi_cell_left = left_ * 2 - 1;
+      int demi_cell_right = right_ * 2 + 2;
+
+      int y = box_.y_min;
+      for (int x = box_.x_min; x <= box_.x_max; ++x) {
+        Pixel& pixel = screen.PixelAt(x, y);
+
+        int a = (x - box_.x_min) * 2;
+        int b = a + 1;
+        bool a_empty = demi_cell_left == a || demi_cell_right == a;
+        bool b_empty = demi_cell_left == b || demi_cell_right == b;
+
+        if (!a_empty && !b_empty) {
+          pixel.character = "─";
+          pixel.automerge = true;
+        } else {
+          pixel.character = a_empty ? "╶" : "╴";
+          pixel.automerge = false;
+        }
+
+        if (demi_cell_left <= a && b <= demi_cell_right)
+          pixel.foreground_color = selected_color_;
+        else
+          pixel.foreground_color = unselected_color_;
+      }
+    }
+
+    float left_;
+    float right_;
+    Color selected_color_;
+    Color unselected_color_;
+  };
+  return std::make_shared<Impl>(left, right, selected_color, unselected_color);
+}
+
+/// @brief Draw an vertical bar, with the area in between up/downcolored
+/// differently.
+/// @param up the left limit of the active area.
+/// @param down the right limit of the active area.
+/// @param selected_color the color of the selected area.
+/// @param unselected_color the color of the unselected area.
+///
+/// ### Example
+///
+/// ```cpp
+/// Element document = separatorHSelector(2,5, Color::White, Color::Blue);
+/// ```
+Element separatorVSelector(float up,
+                           float down,
+                           Color selected_color,
+                           Color unselected_color) {
+  class Impl : public Node {
+   public:
+    Impl(float up, float down, Color selected_color, Color unselected_color)
+        : up_(up),
+          down_(down),
+          selected_color_(selected_color),
+          unselected_color_(unselected_color) {}
+    void ComputeRequirement() override {
+      requirement_.min_x = 1;
+      requirement_.min_y = 1;
+    }
+
+    void Render(Screen& screen) override {
+      if (box_.x_max < box_.x_min)
+        return;
+
+      // This are the two location with an empty demi-cell.
+      int demi_cell_up = up_ * 2 - 1;
+      int demi_cell_down = down_ * 2 + 2;
+
+      int x = box_.x_min;
+      for (int y = box_.y_min; y <= box_.y_max; ++y) {
+        Pixel& pixel = screen.PixelAt(x, y);
+
+        int a = (y - box_.y_min) * 2;
+        int b = a + 1;
+        bool a_empty = demi_cell_up == a || demi_cell_down == a;
+        bool b_empty = demi_cell_up == b || demi_cell_down == b;
+
+        if (!a_empty && !b_empty) {
+          pixel.character = "│";
+          pixel.automerge = true;
+        } else {
+          pixel.character = a_empty ? "╷" : "╵";
+          pixel.automerge = false;
+        }
+
+        if (demi_cell_up <= a && b <= demi_cell_down)
+          pixel.foreground_color = selected_color_;
+        else
+          pixel.foreground_color = unselected_color_;
+      }
+    }
+
+    float up_;
+    float down_;
+    Color selected_color_;
+    Color unselected_color_;
+  };
+  return std::make_shared<Impl>(up, down, selected_color, unselected_color);
+}
+
 }  // namespace ftxui
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.