Move scroll handling to GDScript

Just expose the underlying libtsm methods from gdnative, but write all
the logic in gdscript. Makes it much easier to customize and update.

addons/godot_xterm/native/src/terminal.cpp

@@ -1,11 +1,5 @@
 // Copyright (c) 2021, Leroy Hopson (MIT License).
 
-// This file contains snippets of code taken from Godot's TextEdit node.
-// The snippet code is copyright of its authors and released under the MIT
-// license:
-// - Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur (MIT License).
-// - Copyright (c) 2014-2021 Godot Engine contributors (MIT License).
-
 #include "terminal.h"
 #include <Dictionary.hpp>
 #include <InputEventKey.hpp>
@@ -289,6 +283,9 @@ void Terminal::_register_methods() {
 
   register_method("write", &Terminal::write);
 
+  register_method("sb_up", &Terminal::sb_up);
+  register_method("sb_down", &Terminal::sb_down);
+
   register_method("_update_theme", &Terminal::update_theme);
   register_method("_update_size", &Terminal::update_theme);
 
@@ -366,35 +363,6 @@ void Terminal::_gui_input(Variant event) {
     tsm_vte_handle_keyboard(vte, keysym, ascii, mods,
                             unicode ? unicode : TSM_VTE_INVALID);
   }
-
-  Ref<InputEventMouseButton> mb = event;
-
-  if (mb.is_valid()) {
-    Vector2 mpos = mb->get_position();
-
-    if (mb->is_pressed()) {
-      if (mb->get_button_index() == GLOBAL_CONSTANT(BUTTON_WHEEL_UP)) {
-        if (mb->get_alt()) {
-          // Scroll 5 times as fast as normal (like in TextEdit).
-          tsm_screen_sb_up(screen, 15 * mb->get_factor());
-        } else {
-          // Scroll 3 lines.
-          tsm_screen_sb_up(screen, 3 * mb->get_factor());
-        }
-        update();
-      }
-      if (mb->get_button_index() == GLOBAL_CONSTANT(BUTTON_WHEEL_DOWN)) {
-        if (mb->get_alt()) {
-          // Scroll 5 times as fast as normal (like in TextEdit).
-          tsm_screen_sb_down(screen, 15 * mb->get_factor());
-        } else {
-          // Scroll 3 lines.
-          tsm_screen_sb_down(screen, 3 * mb->get_factor());
-        }
-        update();
-      }
-    }
-  }
 }
 
 void Terminal::_draw() {
@@ -600,3 +568,13 @@ void Terminal::write(String data) {
 
   tsm_vte_input(vte, u8, len);
 }
+
+void Terminal::sb_up(int num) {
+  tsm_screen_sb_up(screen, num);
+  update();
+}
+
+void Terminal::sb_down(int num) {
+  tsm_screen_sb_down(screen, num);
+  update();
+}

addons/godot_xterm/native/src/terminal.h

@@ -56,6 +56,9 @@ public:
 
   void write(String data);
 
+  void sb_up(int num);
+  void sb_down(int num);
+
   enum UpdateMode {
     DISABLED,
     AUTO,

addons/godot_xterm/nodes/terminal/terminal.gd

@@ -1,3 +1,9 @@
+# Copyright (c) 2021, Leroy Hopson (MIT License).
+#
+# This file contains snippets of code derived from Godot's TextEdit node.
+# These snippets are copyright of their authors and released under the MIT license:
+# - Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur (MIT License).
+# - Copyright (c) 2014-2021 Godot Engine contributors (MIT License).
 tool
 extends Control
 
@@ -87,6 +93,28 @@ func _refresh():
 
 func _gui_input(event):
 	_native_terminal._gui_input(event)
+	_handle_mouse_wheel(event)
+
+
+func _handle_mouse_wheel(event: InputEventMouseButton):
+	if not event or not event.is_pressed():
+		return
+
+	if event.button_index == BUTTON_WHEEL_UP:
+		if event.alt:
+			# Scroll 5 times as fast as normal (like TextEdit).
+			_native_terminal.sb_up(15 * event.factor)
+		else:
+			# Scroll 3 lines.
+			_native_terminal.sb_up(3 * event.factor)
+
+	if event.button_index == BUTTON_WHEEL_DOWN:
+		if event.alt:
+			# Scroll 5 times as fast as normal (like TextEdit).
+			_native_terminal.sb_down(15 * event.factor)
+		else:
+			# Scroll 3 lines.
+			_native_terminal.sb_down(3 * event.factor)
 
 
 func _notification(what: int) -> void: