Ensure that the swatches get deleted when the user removes all palettes

src/Autoload/Palettes.gd

@@ -36,9 +36,10 @@ func does_palette_exist(palette_name: String) -> bool:
 
 
 func select_palette(palette_name: String) -> void:
-	current_palette = palettes.get(palette_name)
+	current_palette = palettes.get(palette_name, null)
 	_clear_selected_colors()
-	Global.config_cache.set_value("data", "last_palette", current_palette.name)
+	if is_instance_valid(current_palette):
+		Global.config_cache.set_value("data", "last_palette", current_palette.name)
 	palette_selected.emit(palette_name)
 
 
@@ -224,6 +225,7 @@ func current_palete_delete(permanent := true) -> void:
 		select_palette(palettes.keys()[0])
 	else:
 		current_palette = null
+		select_palette("")
 
 
 func current_palette_add_color(mouse_button: int, start_index := 0) -> void:

src/Classes/ImageExtended.gd

@@ -74,6 +74,8 @@ func select_palette(_name: String, convert_to_rgb := true) -> void:
 
 ## Updates [member palette] to contain the colors of [member current_palette].
 func update_palette() -> void:
+	if not is_instance_valid(current_palette):
+		return
 	if palette.size() != current_palette.colors_max:
 		palette.resize(current_palette.colors_max)
 		palette.fill(TRANSPARENT)
@@ -83,9 +85,9 @@ func update_palette() -> void:
 
 ## Displays the actual RGBA values of each pixel in the image from indexed mode.
 func convert_indexed_to_rgb() -> void:
-	if not is_indexed:
+	if not is_indexed or not is_instance_valid(current_palette):
 		return
-	var palette_image := Palettes.current_palette.convert_to_image(false)
+	var palette_image := current_palette.convert_to_image(false)
 	var palette_texture := ImageTexture.create_from_image(palette_image)
 	var shader_image_effect := ShaderImageEffect.new()
 	var indices_texture := ImageTexture.create_from_image(indices_image)
@@ -97,9 +99,9 @@ func convert_indexed_to_rgb() -> void:
 ## Automatically maps each color of the image's pixel to the closest color of the palette,
 ## by finding the palette color's index and storing it in [member indices_image].
 func convert_rgb_to_indexed() -> void:
-	if not is_indexed:
+	if not is_indexed or not is_instance_valid(current_palette):
 		return
-	var palette_image := Palettes.current_palette.convert_to_image(false)
+	var palette_image := current_palette.convert_to_image(false)
 	var palette_texture := ImageTexture.create_from_image(palette_image)
 	var params := {
 		"palette_texture": palette_texture, "rgb_texture": ImageTexture.create_from_image(self)

src/Palette/PaletteGrid.gd

@@ -23,10 +23,6 @@ func _ready() -> void:
 
 
 func set_palette(new_palette: Palette) -> void:
-	# Only display valid palette objects
-	if not new_palette:
-		return
-
 	current_palette = new_palette
 	grid_window_origin = Vector2.ZERO
 
@@ -87,6 +83,8 @@ func scroll_palette(origin: Vector2i) -> void:
 ## Called when the color changes, either the left or the right, determined by [param mouse_button].
 ## If current palette has [param target_color] as a [Color], then select it.
 func find_and_select_color(target_color: Color, mouse_button: int) -> void:
+	if not is_instance_valid(current_palette):
+		return
 	var old_index := Palettes.current_palette_get_selected_color_index(mouse_button)
 	for color_ind in swatches.size():
 		if (
@@ -115,6 +113,8 @@ func find_and_select_color(target_color: Color, mouse_button: int) -> void:
 
 ## Displays a left/right highlight over a swatch
 func select_swatch(mouse_button: int, palette_index: int, old_palette_index: int) -> void:
+	if not is_instance_valid(current_palette):
+		return
 	var index := convert_palette_index_to_grid_index(palette_index)
 	var old_index := convert_palette_index_to_grid_index(old_palette_index)
 	if index >= 0 and index < swatches.size():
@@ -159,16 +159,17 @@ func convert_palette_index_to_grid_index(palette_index: int) -> int:
 
 
 func resize_grid(new_rect_size: Vector2) -> void:
-	if not is_instance_valid(current_palette):
-		return
 	var grid_x: int = (
 		new_rect_size.x / (swatch_size.x + get("theme_override_constants/h_separation"))
 	)
 	var grid_y: int = (
 		new_rect_size.y / (swatch_size.y + get("theme_override_constants/v_separation"))
 	)
-	grid_size.x = mini(grid_x, current_palette.width)
-	grid_size.y = mini(grid_y, current_palette.height)
+	if is_instance_valid(current_palette):
+		grid_size.x = mini(grid_x, current_palette.width)
+		grid_size.y = mini(grid_y, current_palette.height)
+	else:
+		grid_size = Vector2i.ZERO
 	setup_swatches()
 	draw_palette()
 

src/Palette/PalettePanel.gd

@@ -89,16 +89,16 @@ func select_palette(palette_name: String) -> void:
 	var palette_id = palettes_path_id.get(palette_name)
 	if palette_id != null:
 		palette_select.selected = palette_id
-		palette_grid.set_palette(Palettes.current_palette)
-		palette_scroll.resize_grid()
-		palette_scroll.set_sliders(Palettes.current_palette, palette_grid.grid_window_origin)
+	palette_grid.set_palette(Palettes.current_palette)
+	palette_scroll.resize_grid()
+	palette_scroll.set_sliders(Palettes.current_palette, palette_grid.grid_window_origin)
 
-		var left_selected := Palettes.current_palette_get_selected_color_index(MOUSE_BUTTON_LEFT)
-		var right_selected := Palettes.current_palette_get_selected_color_index(MOUSE_BUTTON_RIGHT)
-		palette_grid.select_swatch(MOUSE_BUTTON_LEFT, left_selected, left_selected)
-		palette_grid.select_swatch(MOUSE_BUTTON_RIGHT, right_selected, right_selected)
+	var left_selected := Palettes.current_palette_get_selected_color_index(MOUSE_BUTTON_LEFT)
+	var right_selected := Palettes.current_palette_get_selected_color_index(MOUSE_BUTTON_RIGHT)
+	palette_grid.select_swatch(MOUSE_BUTTON_LEFT, left_selected, left_selected)
+	palette_grid.select_swatch(MOUSE_BUTTON_RIGHT, right_selected, right_selected)
 
-		toggle_add_delete_buttons()
+	toggle_add_delete_buttons()
 
 
 ## Select and display current palette
@@ -115,6 +115,8 @@ func redraw_current_palette() -> void:
 
 
 func toggle_add_delete_buttons() -> void:
+	if not is_instance_valid(Palettes.current_palette):
+		return
 	add_color_button.disabled = Palettes.current_palette.is_full()
 	if add_color_button.disabled:
 		add_color_button.mouse_default_cursor_shape = CURSOR_FORBIDDEN

src/Palette/PaletteScroll.gd

@@ -4,9 +4,9 @@ var scroll := Vector2i.ZERO
 var drag_started := false
 var drag_start_position := Vector2i.ZERO
 
-@onready var h_slider := %HScrollBar
-@onready var v_slider := %VScrollBar
-@onready var palette_grid := %PaletteGrid
+@onready var h_slider := %HScrollBar as HScrollBar
+@onready var v_slider := %VScrollBar as VScrollBar
+@onready var palette_grid := %PaletteGrid as PaletteGrid
 
 
 func _input(event: InputEvent) -> void:
@@ -17,16 +17,21 @@ func _input(event: InputEvent) -> void:
 
 
 func set_sliders(palette: Palette, origin: Vector2i) -> void:
-	if not is_instance_valid(palette):
-		return
-	h_slider.value = origin.x
-	h_slider.max_value = palette.width
-	h_slider.page = palette_grid.grid_size.x
+	if is_instance_valid(palette):
+		h_slider.value = origin.x
+		h_slider.max_value = palette.width
+		h_slider.page = palette_grid.grid_size.x
+		v_slider.value = origin.y
+		v_slider.max_value = palette.height
+		v_slider.page = palette_grid.grid_size.y
+	else:
+		h_slider.value = 0
+		h_slider.max_value = 0
+		h_slider.page = 0
+		v_slider.value = 0
+		v_slider.max_value = 0
+		v_slider.page = 0
 	h_slider.visible = false if h_slider.max_value <= palette_grid.grid_size.x else true
-
-	v_slider.value = origin.y
-	v_slider.max_value = palette.height
-	v_slider.page = palette_grid.grid_size.y
 	v_slider.visible = false if v_slider.max_value <= palette_grid.grid_size.y else true
 
 
@@ -58,7 +63,7 @@ func _on_PaletteGrid_gui_input(event: InputEvent) -> void:
 			drag_started = true
 			# Keeps position where the dragging started
 			drag_start_position = (
-				event.position + Vector2i(h_slider.value, v_slider.value) * palette_grid.swatch_size
+				event.position + Vector2(h_slider.value, v_slider.value) * palette_grid.swatch_size
 			)
 
 	if event is InputEventMouseMotion and drag_started: