Custom brushes, crop image, split screen, about menu & asset re-organizing

- Added support for custom brushes. When you Ctrl-C a selection, it gets added to the list of custom brushes. Each mouse button can have a different brush, and the user can choose whether their color comes from the brush itself or the selected color in the tool options. They can also be resized based on the selected brush size.
- Custom brushes are also being saved on .pxo files.
- You can now crop images (per frame). All layers of that frame are taken into account and are affected.
- Added split screen support. The user can toggle between single screen and split screen, where a second canvas is being shown. Note that you cannot draw on the second canvas.
- Added an About Pixelorama selection on the new Help menu.
- Project assets are re-organized.

Scripts/Global.gd

@@ -18,28 +18,34 @@ var draw_grid := false
 var canvases := []
 var canvas : Canvas
 var canvas_parent : Node
+var second_viewport : ViewportContainer
+var viewport_separator : VSeparator
+var split_screen_button : Button
 # warning-ignore:unused_class_variable
 var left_square_indicator_visible := true
 # warning-ignore:unused_class_variable
 var right_square_indicator_visible := false
-# warning-ignore:unused_class_variable
-var left_brush_size := 1
-# warning-ignore:unused_class_variable
-var right_brush_size := 1
 var camera : Camera2D
+var camera2 : Camera2D
 var selection_rectangle : Polygon2D
+# warning-ignore:unused_class_variable
 var selected_pixels := []
 var image_clipboard : Image
 
 var file_menu : MenuButton
 var edit_menu : MenuButton
 var view_menu : MenuButton
+var help_menu : MenuButton
 var left_indicator : Sprite
 var right_indicator : Sprite
 var left_color_picker : ColorPickerButton
 var right_color_picker : ColorPickerButton
 var left_brush_size_edit : SpinBox
 var right_brush_size_edit : SpinBox
+var left_interpolate_slider : HSlider
+var right_interpolate_slider : HSlider
+
+
 var loop_animation_button : Button
 var play_forward : Button
 var play_backwards : Button
@@ -60,12 +66,34 @@ var current_left_tool := "Pencil"
 # warning-ignore:unused_class_variable
 var current_right_tool := "Eraser"
 
+#Brushes
+enum BRUSH_TYPES {PIXEL, CUSTOM}
+# warning-ignore:unused_class_variable
+var left_brush_size := 1
+# warning-ignore:unused_class_variable
+var right_brush_size := 1
+# warning-ignore:unused_class_variable
+var current_left_brush_type = BRUSH_TYPES.PIXEL
+# warning-ignore:unused_class_variable
+var current_right_brush_type = BRUSH_TYPES.PIXEL
+# warning-ignore:unused_class_variable
+var custom_brushes := []
+# warning-ignore:unused_class_variable
+var custom_left_brush_index := -1
+# warning-ignore:unused_class_variable
+var custom_right_brush_index := -1
+
+
 func _ready() -> void:
 	var root = get_tree().get_root()
 	canvas = find_node_by_name(root, "Canvas")
 	canvases.append(canvas)
 	canvas_parent = canvas.get_parent()
+	second_viewport = find_node_by_name(root, "ViewportContainer2")
+	viewport_separator = find_node_by_name(root, "ViewportSeparator")
+	split_screen_button = find_node_by_name(root, "SplitScreenButton")
 	camera = find_node_by_name(canvas_parent, "Camera2D")
+	camera2 = find_node_by_name(canvas_parent.get_parent().get_parent(), "Camera2D2")
 	
 	selection_rectangle = find_node_by_name(root, "SelectionRectangle")
 	image_clipboard = Image.new()
@@ -73,12 +101,15 @@ func _ready() -> void:
 	file_menu = find_node_by_name(root, "FileMenu")
 	edit_menu = find_node_by_name(root, "EditMenu")
 	view_menu = find_node_by_name(root, "ViewMenu")
+	help_menu = find_node_by_name(root, "HelpMenu")
 	left_indicator = find_node_by_name(root, "LeftIndicator")
 	right_indicator = find_node_by_name(root, "RightIndicator")
 	left_color_picker = find_node_by_name(root, "LeftColorPickerButton")
 	right_color_picker = find_node_by_name(root, "RightColorPickerButton")
 	left_brush_size_edit = find_node_by_name(root, "LeftBrushSizeEdit")
 	right_brush_size_edit = find_node_by_name(root, "RightBrushSizeEdit")
+	left_interpolate_slider = find_node_by_name(root, "LeftInterpolateFactor")
+	right_interpolate_slider = find_node_by_name(root, "RightInterpolateFactor")
 	
 	loop_animation_button = find_node_by_name(root, "LoopAnim")
 	play_forward = find_node_by_name(root, "PlayForward")
@@ -133,4 +164,14 @@ func handle_layer_order_buttons() -> void:
 
 func set_current_frame_label(value) -> void:
 	current_frame = value
-	current_frame_label.text = "Current frame: %s/%s" % [str(current_frame + 1), canvases.size()]
+	current_frame_label.text = "Current frame: %s/%s" % [str(current_frame + 1), canvases.size()]
+
+func create_brush_button(brush_img : Image) -> void:
+	var brush_button = load("res://Prefabs/BrushButton.tscn").instance()
+	brush_button.brush_type = Global.BRUSH_TYPES.CUSTOM
+	brush_button.custom_brush_index = Global.custom_brushes.size() - 1
+	var brush_tex := ImageTexture.new()
+	brush_tex.create_from_image(brush_img, 0)
+	brush_button.get_child(0).texture = brush_tex
+	var hbox_container := find_node_by_name(get_tree().get_root(), "BrushHBoxContainer")
+	hbox_container.add_child(brush_button)