From 3bed9e7b0f39d6ccecfea19dbc932a9ad030e50e Mon Sep 17 00:00:00 2001
From: Leroy Hopson <git@leroy.geek.nz>
Date: Thu, 15 Feb 2024 18:54:20 +1300
Subject: [PATCH] Add scroll support

---
 addons/godot_xterm/native/src/terminal.cpp | 26 ++++++++++++++++++++++
 addons/godot_xterm/native/src/terminal.h   |  3 +++
 2 files changed, 29 insertions(+)

diff --git a/addons/godot_xterm/native/src/terminal.cpp b/addons/godot_xterm/native/src/terminal.cpp
index 71597b5..b96c248 100644
--- a/addons/godot_xterm/native/src/terminal.cpp
+++ b/addons/godot_xterm/native/src/terminal.cpp
@@ -176,6 +176,7 @@ String Terminal::write(const Variant data)
 void Terminal::_gui_input(const Ref<InputEvent> &event) {
 	_handle_key_input(event);
 	_handle_selection(event);
+	_handle_mouse_wheel(event);
 }
 
 void Terminal::_notification(int what)
@@ -658,6 +659,31 @@ void Terminal::_handle_key_input(Ref<InputEventKey> event) {
       accept_event();
 }
 
+void Terminal::_handle_mouse_wheel(Ref<InputEventMouseButton> event) {
+  if (!event.is_valid() || !event->is_pressed())
+    return;
+
+  void (*scroll_func)(tsm_screen *, unsigned int) = nullptr;
+
+  switch (event->get_button_index()) {
+  case MOUSE_BUTTON_WHEEL_UP:
+    scroll_func = &tsm_screen_sb_up;
+    break;
+  case MOUSE_BUTTON_WHEEL_DOWN:
+    scroll_func = &tsm_screen_sb_down;
+    break;
+  };
+
+  if (scroll_func != nullptr) {
+    // Scroll 5 times as fast as normal if alt is pressed (like TextEdit).
+    // Otherwise, just scroll 3 lines.
+    int speed = event->is_alt_pressed() ? 15 : 3;
+    double factor = event->get_factor();
+    (*scroll_func)(screen, speed * factor);
+    queue_redraw();
+  }
+}
+
 void Terminal::_handle_selection(Ref<InputEventMouse> event) {
   if (!event.is_valid())
     return;
diff --git a/addons/godot_xterm/native/src/terminal.h b/addons/godot_xterm/native/src/terminal.h
index 2b2a73e..85f8160 100644
--- a/addons/godot_xterm/native/src/terminal.h
+++ b/addons/godot_xterm/native/src/terminal.h
@@ -9,6 +9,7 @@
 #include <godot_cpp/classes/image_texture.hpp>
 #include <godot_cpp/classes/input_event_key.hpp>
 #include <godot_cpp/classes/input_event_mouse.hpp>
+#include <godot_cpp/classes/input_event_mouse_button.hpp>
 #include <godot_cpp/classes/rendering_server.hpp>
 #include <godot_cpp/classes/shader_material.hpp>
 #include <godot_cpp/classes/timer.hpp>
@@ -154,6 +155,8 @@ namespace godot
     void initialize_input();
     void _handle_key_input(Ref<InputEventKey> event);
 
+    void _handle_mouse_wheel(Ref<InputEventMouseButton> event);
+
     enum SelectionMode { NONE, POINTER };
     bool selecting = false;
     SelectionMode selection_mode = SelectionMode::NONE;