Allow creating ResourceProjects through ExtensionsApi (#1345)

* Allow creating resource projects through Api

* Fix errors appearing when signal is already connected or disconnected

* Formatting

* Added a  method to the ResourceProject

* Formatting

* Add docs

Author: Variable-ind

src/Autoload/ExtensionsApi.gd

@@ -581,18 +581,24 @@ class ProjectAPI:
 	## name [param name], size [param size], fill color [param fill_color] and
 	## frames [param frames]. The created project also gets returned.[br][br]
 	## [param frames] is an [Array] of type [Frame]. Usually it can be left as [code][][/code].
+	## If [param is_resource] is [code]true[/code] then a [ResourceProject] is created.
 	func new_project(
 		frames: Array[Frame] = [],
 		name := tr("untitled"),
 		size := Vector2(64, 64),
-		fill_color := Color.TRANSPARENT
+		fill_color := Color.TRANSPARENT,
+		is_resource := false
 	) -> Project:
 		if !name.is_valid_filename():
 			name = tr("untitled")
 		if size.x <= 0 or size.y <= 0:
 			size.x = 1
 			size.y = 1
-		var new_proj := Project.new(frames, name, size.floor())
+		var new_proj: Project
+		if is_resource:
+			new_proj = ResourceProject.new(frames, name, size.floor())
+		else:
+			new_proj = Project.new(frames, name, size.floor())
 		new_proj.layers.append(PixelLayer.new(new_proj))
 		new_proj.fill_color = fill_color
 		new_proj.frames.append(new_proj.new_empty_frame())
@@ -617,8 +623,13 @@ class ProjectAPI:
 	## Creates and returns a new [Project] in a new tab, with an optional [param name].
 	## Unlike [method new_project], no starting frame/layer gets created.
 	## Useful if you want to deserialize project data.
-	func new_empty_project(name := tr("untitled")) -> Project:
-		var new_proj := Project.new([], name)
+	## If [param is_resource] is [code]true[/code] then a [ResourceProject] is created.
+	func new_empty_project(name := tr("untitled"), is_resource := false) -> Project:
+		var new_proj: Project
+		if is_resource:
+			new_proj = ResourceProject.new([], name)
+		else:
+			new_proj = Project.new([], name)
 		Global.projects.append(new_proj)
 		return new_proj
 
@@ -868,11 +879,13 @@ class SignalsAPI:
 		signal_class: Signal, callable: Callable, is_disconnecting := false
 	) -> void:
 		if !is_disconnecting:
-			signal_class.connect(callable)
-			ExtensionsApi.add_action("SignalsAPI", signal_class.get_name())
+			if not signal_class.is_connected(callable):
+				signal_class.connect(callable)
+				ExtensionsApi.add_action("SignalsAPI", signal_class.get_name())
 		else:
-			signal_class.disconnect(callable)
-			ExtensionsApi.remove_action("SignalsAPI", signal_class.get_name())
+			if signal_class.is_connected(callable):
+				signal_class.disconnect(callable)
+				ExtensionsApi.remove_action("SignalsAPI", signal_class.get_name())
 
 	# APP RELATED SIGNALS
 	## Connects/disconnects a signal to [param callable], that emits

src/Classes/ResourceProject.gd

@@ -1,9 +1,31 @@
 class_name ResourceProject
 extends Project
+## A class for easily editing individual project sub-resources like tiles, index maps, etc.
+##
+## The [ResourceProject] is basically a [Project], except that it doesn't get saved physically
+## (as a .pxo file), instead, a [signal resource_updated] signal is emitted which can
+## be used to update the resource in the [Project].[br]
 
+## Emitted when the [ResourceProject] is saved.
 @warning_ignore("unused_signal")
-signal resource_updated
+signal resource_updated(project: Project)
 
 
 func _init(_frames: Array[Frame] = [], _name := tr("untitled"), _size := Vector2i(64, 64)) -> void:
 	super._init(_frames, _name + " (Virtual Resource)", _size)
+
+
+## Returns the full image of the [Frame] at [param frame_idx] in resource project.
+func get_frame_image(frame_idx: int) -> Image:
+	var frame_image := Image.create_empty(size.x, size.y, false, Image.FORMAT_RGBA8)
+	if frame_idx >= 0 and frame_idx < frames.size():
+		var frame := frames[frame_idx]
+		DrawingAlgos.blend_layers(frame_image, frame, Vector2i.ZERO, self)
+	else:
+		printerr(
+			(
+				"frame index: %s not found in ResourceProject, frames.size(): %s"
+				% [str(frame_idx), str(frames.size())]
+			)
+		)
+	return frame_image

src/Classes/ShaderLoader.gd

@@ -660,11 +660,7 @@ static func _shader_update_texture(
 	if resource_proj.layers.size() > 1:
 		warnings += "\nThis resource is intended to have 1 layer only. layers will be blended."
 
-	var updated_image := Image.create_empty(
-		resource_proj.size.x, resource_proj.size.y, false, Image.FORMAT_RGBA8
-	)
-	var frame := resource_proj.frames[0]
-	DrawingAlgos.blend_layers(updated_image, frame, Vector2i.ZERO, resource_proj)
+	var updated_image := resource_proj.get_frame_image(0)
 	value_changed.call(ImageTexture.create_from_image(updated_image), parameter_name)
 	if not warnings.is_empty():
 		Global.popup_error(warnings)

src/UI/TilesPanel.gd

@@ -169,11 +169,7 @@ static func _update_tile(
 	if resource_proj.layers.size() > 1:
 		warnings += "\nThis resource is intended to have 1 layer only. layers will be blended."
 
-	var updated_image := Image.create_empty(
-		resource_proj.size.x, resource_proj.size.y, false, Image.FORMAT_RGBA8
-	)
-	var frame := resource_proj.frames[0]
-	DrawingAlgos.blend_layers(updated_image, frame, Vector2i.ZERO, resource_proj)
+	var updated_image := resource_proj.get_frame_image(0)
 	if is_instance_valid(target_project) and is_instance_valid(tileset):
 		if tile_idx < tileset.tiles.size():
 			if !tileset.tiles[tile_idx].image: