From 53f179c776ab942ca6373b5c58b3c29e222705d6 Mon Sep 17 00:00:00 2001
From: Clement Roblot <clement.roblot@martobre.fr>
Date: Fri, 2 Aug 2024 23:08:24 +0700
Subject: [PATCH] Prevent spamming

---
 examples/component/input.cpp   |  1 -
 include/ftxui/dom/elements.hpp |  1 +
 src/ftxui/dom/selectable.cpp   | 30 ++++++++++++++++++------------
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/examples/component/input.cpp b/examples/component/input.cpp
index 23962ce5..a4c31ece 100644
--- a/examples/component/input.cpp
+++ b/examples/component/input.cpp
@@ -74,7 +74,6 @@ int main() {
   // TODO: Implement the double click on word to select the word
   // TODO: Implement the double click and drag to select word by word (optional)
   // TODO: Implement the tripple click to select an entire line 
-  // TODO: Call onSelectionChange_ only when the selection indeed did change, not at every render?
   // TODO: Add a "selectable" flag in the pixel class and take it into account when selecting things
 
   renderer |= CatchEvent([&](Event event) { 
diff --git a/include/ftxui/dom/elements.hpp b/include/ftxui/dom/elements.hpp
index 4579c8a8..f2a65b47 100644
--- a/include/ftxui/dom/elements.hpp
+++ b/include/ftxui/dom/elements.hpp
@@ -40,6 +40,7 @@ typedef struct {
   uint16_t endx = 0;
   uint16_t starty = 0;
   uint16_t endy = 0;
+  bool changed = false;
 } Region;
 
 // Pipe elements into decorator togethers.
diff --git a/src/ftxui/dom/selectable.cpp b/src/ftxui/dom/selectable.cpp
index f88a0274..d1482ff0 100644
--- a/src/ftxui/dom/selectable.cpp
+++ b/src/ftxui/dom/selectable.cpp
@@ -12,7 +12,7 @@
 
 namespace ftxui {
 
-Region newSelection;
+Region selectedRegion;
 
 namespace {
 class Selectable : public NodeDecorator {
@@ -24,14 +24,17 @@ class Selectable : public NodeDecorator {
   void Render(Screen& screen) override {
     Node::Render(screen);
     std::string selectedText = "";
-    for (int y = std::min(newSelection.starty, newSelection.endy); y <= std::max(newSelection.starty, newSelection.endy); ++y) {
-      for (int x = std::min(newSelection.startx, newSelection.endx); x <= std::max(newSelection.startx, newSelection.endx)-1; ++x) {
+    for (int y = std::min(selectedRegion.starty, selectedRegion.endy); y <= std::max(selectedRegion.starty, selectedRegion.endy); ++y) {
+      for (int x = std::min(selectedRegion.startx, selectedRegion.endx); x <= std::max(selectedRegion.startx, selectedRegion.endx)-1; ++x) {
         screen.PixelAt(x, y).inverted ^= true;
         selectedText += screen.PixelAt(x, y).character;
       }
     }
 
-    onSelectionChange_(selectedText);
+    if(selectedRegion.changed == true) {
+      selectedRegion.changed = false;;
+      onSelectionChange_(selectedText);
+    }
   }
 
 private:
@@ -58,16 +61,19 @@ bool selectableCatchEvent(Event event) {
       if (mouse.button == Mouse::Left) {
 
         if (mouse.motion == Mouse::Pressed) {
-          newSelection.startx = mouse.x;
-          newSelection.starty = mouse.y;
-          newSelection.endx = mouse.x;
-          newSelection.endy = mouse.y;
+          selectedRegion.startx = mouse.x;
+          selectedRegion.starty = mouse.y;
+          selectedRegion.endx = mouse.x;
+          selectedRegion.endy = mouse.y;
+          selectedRegion.changed = true;
         } else if (mouse.motion == Mouse::Released) {
-          newSelection.endx = mouse.x;
-          newSelection.endy = mouse.y;
+          selectedRegion.endx = mouse.x;
+          selectedRegion.endy = mouse.y;
+          selectedRegion.changed = true;
         } else if (mouse.motion == Mouse::Moved) {
-          newSelection.endx = mouse.x;
-          newSelection.endy = mouse.y;
+          selectedRegion.endx = mouse.x;
+          selectedRegion.endy = mouse.y;
+          selectedRegion.changed = true;
         }
 
         return true;