From 03b173b76e9d0cebd5bd7497208481da43392abe Mon Sep 17 00:00:00 2001
From: Emmanouil Papadeas <manoschool@yahoo.gr>
Date: Fri, 15 Mar 2024 01:31:12 +0200
Subject: [PATCH] Optimize cel switching by avoiding changing the stylebox of
 every CelButton

---
 src/Autoload/Global.gd          |  6 +++++-
 src/Preferences/HandleThemes.gd |  1 +
 src/UI/Timeline/CelButton.gd    | 29 +++++++++++++----------------
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/src/Autoload/Global.gd b/src/Autoload/Global.gd
index 9c16ce45d..087317692 100644
--- a/src/Autoload/Global.gd
+++ b/src/Autoload/Global.gd
@@ -12,6 +12,10 @@ signal project_about_to_switch  ## Emitted before a project is about to be switc
 signal project_switched  ## Emitted whenever you switch to some other project tab.
 signal cel_switched  ## Emitted whenever you select a different cel.
 signal project_data_changed(project: Project)  ## Emitted when project data is modified.
+## Emitted when the theme is switched. Unlike [signal Control.theme_changed],
+## this doesn't get emitted when a stylebox of a control changes, only when the
+## main theme gets switched to another.
+signal theme_switched
 
 enum LayerTypes { PIXEL, GROUP, THREE_D }
 enum GridTypes { CARTESIAN, ISOMETRIC, ALL }
@@ -466,7 +470,7 @@ var cel_button_scene: PackedScene = load("res://src/UI/Timeline/CelButton.tscn")
 
 @onready var main_window := get_window()  ## The main Pixelorama [Window].
 ## The control node (aka Main node). It has the [param Main.gd] script attached.
-@onready var control := get_tree().current_scene
+@onready var control := get_tree().current_scene as Control
 
 ## The project tabs bar. It has the [param Tabs.gd] script attached.
 @onready var tabs: TabBar = control.find_child("TabBar")
diff --git a/src/Preferences/HandleThemes.gd b/src/Preferences/HandleThemes.gd
index 976b58620..96a00682e 100644
--- a/src/Preferences/HandleThemes.gd
+++ b/src/Preferences/HandleThemes.gd
@@ -83,6 +83,7 @@ func change_theme(id: int) -> void:
 	Global.control.theme = theme
 	change_clear_color()
 	change_icon_colors()
+	Global.theme_switched.emit()
 
 
 func change_clear_color() -> void:
diff --git a/src/UI/Timeline/CelButton.gd b/src/UI/Timeline/CelButton.gd
index 07cafe1e4..c08854db0 100644
--- a/src/UI/Timeline/CelButton.gd
+++ b/src/UI/Timeline/CelButton.gd
@@ -6,10 +6,7 @@ var frame := 0
 var layer := 0
 var cel: BaseCel
 
-## Without this variable, [signal Control.theme_changed] calls [method cel_switched], which calls
-## [method Control.add_theme_stylebox_override], firing [signal Control.theme_changed]
-## and thus resulting in an endless loop.
-var _call_theme_changed := true
+var _is_guide_stylebox := false
 
 @onready var popup_menu: PopupMenu = get_node_or_null("PopupMenu")
 @onready var linked: ColorRect = $Linked
@@ -20,7 +17,7 @@ var _call_theme_changed := true
 
 func _ready() -> void:
 	Global.cel_switched.connect(cel_switched)
-	theme_changed.connect(cel_switched)
+	Global.theme_switched.connect(cel_switched.bind(true))
 	cel = Global.current_project.frames[frame].cels[layer]
 	button_setup()
 	_dim_checker()
@@ -32,24 +29,24 @@ func _ready() -> void:
 		transparent_checker.visible = false
 
 
-func cel_switched() -> void:
-	if not _call_theme_changed:
-		_call_theme_changed = true
-		return
-	var current_theme: Theme = Global.control.theme
+func cel_switched(force_stylebox_change := false) -> void:
+	z_index = 1 if button_pressed else 0
+	var current_theme := Global.control.theme
 	var is_guide := false
 	for selected in Global.current_project.selected_cels:
 		if selected[1] == layer or selected[0] == frame:
 			is_guide = true
 			break
-	_call_theme_changed = false
 	if is_guide:
-		var guide_stylebox := current_theme.get_stylebox("guide", "CelButton")
-		add_theme_stylebox_override("normal", guide_stylebox)
+		if not _is_guide_stylebox or force_stylebox_change:
+			var guide_stylebox := current_theme.get_stylebox("guide", "CelButton")
+			add_theme_stylebox_override("normal", guide_stylebox)
+			_is_guide_stylebox = true
 	else:
-		var normal_stylebox := current_theme.get_stylebox("normal", "CelButton")
-		add_theme_stylebox_override("normal", normal_stylebox)
-	z_index = 1 if button_pressed else 0
+		if _is_guide_stylebox or force_stylebox_change:
+			var normal_stylebox := current_theme.get_stylebox("normal", "CelButton")
+			add_theme_stylebox_override("normal", normal_stylebox)
+			_is_guide_stylebox = false
 
 
 func button_setup() -> void: