Created an ImageEffect class

This will be the parent of all (or most) image effect dialog nodes. Currently only parent on FlipImageDialog, will change to be parent of the rest of the effects.

src/Classes/ImageEffect.gd

@@ -0,0 +1,77 @@
+class_name ImageEffect extends AcceptDialog
+# Parent class for all image effects
+# Methods that have "pass" are meant to be replaced by the inherited Scripts
+
+
+enum {CEL, FRAME, ALL_FRAMES, ALL_PROJECTS}
+
+var affect : int = CEL
+var pixels := []
+var current_cel : Image
+var preview_image : Image
+var preview_texture : ImageTexture
+var preview : TextureRect
+var selection_checkbox : CheckBox
+
+
+func _ready() -> void:
+	set_nodes()
+	current_cel = Image.new()
+	preview_image = Image.new()
+	preview_texture = ImageTexture.new()
+	connect("about_to_show", self, "_about_to_show")
+	connect("popup_hide", self, "_popup_hide")
+	connect("confirmed", self, "_confirmed")
+	if selection_checkbox:
+		selection_checkbox.connect("toggled", self, "_on_SelectionCheckBox_toggled")
+
+
+func _about_to_show() -> void:
+	current_cel = Global.current_project.frames[Global.current_project.current_frame].cels[Global.current_project.current_layer].image
+	if selection_checkbox:
+		_on_SelectionCheckBox_toggled(selection_checkbox.pressed)
+	update_transparent_background_size()
+
+
+func _confirmed() -> void:
+	pass
+
+
+func set_nodes() -> void:
+	pass
+
+
+func _on_SelectionCheckBox_toggled(button_pressed : bool) -> void:
+	pixels.clear()
+	if button_pressed:
+		pixels = Global.current_project.selected_pixels.duplicate()
+	else:
+		for x in Global.current_project.size.x:
+			for y in Global.current_project.size.y:
+				pixels.append(Vector2(x, y))
+
+	update_preview()
+
+
+func update_preview() -> void:
+	pass
+
+
+func update_transparent_background_size() -> void:
+	if !preview:
+		return
+	var image_size_y = preview.rect_size.y
+	var image_size_x = preview.rect_size.x
+	if preview_image.get_size().x > preview_image.get_size().y:
+		var scale_ratio = preview_image.get_size().x / image_size_x
+		image_size_y = preview_image.get_size().y / scale_ratio
+	else:
+		var scale_ratio = preview_image.get_size().y / image_size_y
+		image_size_x = preview_image.get_size().x / scale_ratio
+
+	preview.get_node("TransparentChecker").rect_size.x = image_size_x
+	preview.get_node("TransparentChecker").rect_size.y = image_size_y
+
+
+func _popup_hide() -> void:
+	Global.dialog_open(false)