Implement indexed mode (#1136)

* Create a custom PixeloramaImage class, initial support for indexed mode

* Convert opened projects and images to indexed mode

* Use shaders for RGB to Indexed conversion and vice versa

* Add `is_indexed` variable in PixeloramaImage

* Basic undo/redo support for indexed mode when drawing

* Make image effects respect indexed mode

* Move code from image effects to ShaderImageEffect instead

* Bucket tool works with indexed mode

* Move and selection tools works with indexed mode

* Brushes respect indexed mode

* Add color_mode variable and some helper methods in Project

Replace hard-coded cases of Image.FORMAT_RGBA8 with `Project.get_image_format()` just in case we want to add more formats in the future

* Add a helper new_empty_image() method to Project

* Set new images to indexed if the project is indexed

* Change color modes from the Image menu

* Fix open image to replace cel

* Load/save indices in pxo files

* Merging layers works with indexed mode

* Layer effects respect indexed mode

* Add an `other_image` parameter to `PixeloramaImage.add_data_to_dictionary()`

* Scale image works with indexed mode

* Resizing works with indexed mode

* Fix non-shader rotation not working with indexed mode

* Minor refactor of PixeloramaImage's set_pixelv_custom()

* Make the text tool work with indexed mode

* Remove print from PixeloramaImage

* Rename "PixeloramaImage" to "ImageExtended"

* Add docstrings in ImageExtended

* Set color mode from the create new image dialog

* Update Translations.pot

* Show the color mode in the project properties dialog

Translations/Translations.pot

@@ -156,6 +156,18 @@ msgstr ""
 msgid "Percentage"
 msgstr ""
 
+#. Found in the create new image dialog. Allows users to change the color mode of the new project, such as RGBA or indexed mode.
+msgid "Color mode:"
+msgstr ""
+
+#. Found in the image menu. A submenu that allows users to change the color mode of the project, such as RGBA or indexed mode.
+msgid "Color Mode"
+msgstr ""
+
+#. Found in the image menu, under the "Color Mode" submenu. Refers to the indexed color mode. See this wikipedia page for more information: https://en.wikipedia.org/wiki/Indexed_color
+msgid "Indexed"
+msgstr ""
+
 #. Found in the image menu. Sets the size of the project to be the same as the size of the active selection.
 msgid "Crop to Selection"
 msgstr ""

src/Autoload/DrawingAlgos.gd

@@ -217,7 +217,7 @@ func get_ellipse_points_filled(pos: Vector2i, size: Vector2i, thickness := 1) ->
 
 func scale_3x(sprite: Image, tol := 0.196078) -> Image:
 	var scaled := Image.create(
-		sprite.get_width() * 3, sprite.get_height() * 3, false, Image.FORMAT_RGBA8
+		sprite.get_width() * 3, sprite.get_height() * 3, sprite.has_mipmaps(), sprite.get_format()
 	)
 	var width_minus_one := sprite.get_width() - 1
 	var height_minus_one := sprite.get_height() - 1
@@ -509,6 +509,8 @@ func similar_colors(c1: Color, c2: Color, tol := 0.392157) -> bool:
 func center(indices: Array) -> void:
 	var project := Global.current_project
 	Global.canvas.selection.transform_content_confirm()
+	var redo_data := {}
+	var undo_data := {}
 	project.undos += 1
 	project.undo_redo.create_action("Center Frames")
 	for frame in indices:
@@ -528,15 +530,20 @@ func center(indices: Array) -> void:
 		for cel in project.frames[frame].cels:
 			if not cel is PixelCel:
 				continue
-			var sprite := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
-			sprite.blend_rect(cel.image, used_rect, offset)
-			Global.undo_redo_compress_images({cel.image: sprite.data}, {cel.image: cel.image.data})
+			var cel_image := (cel as PixelCel).get_image()
+			var tmp_centered := project.new_empty_image()
+			tmp_centered.blend_rect(cel.image, used_rect, offset)
+			var centered := ImageExtended.new()
+			centered.copy_from_custom(tmp_centered, cel_image.is_indexed)
+			centered.add_data_to_dictionary(redo_data, cel_image)
+			cel_image.add_data_to_dictionary(undo_data)
+	Global.undo_redo_compress_images(redo_data, undo_data)
 	project.undo_redo.add_undo_method(Global.undo_or_redo.bind(true))
 	project.undo_redo.add_do_method(Global.undo_or_redo.bind(false))
 	project.undo_redo.commit_action()
 
 
-func scale_image(width: int, height: int, interpolation: int) -> void:
+func scale_project(width: int, height: int, interpolation: int) -> void:
 	var redo_data := {}
 	var undo_data := {}
 	for f in Global.current_project.frames:
@@ -544,30 +551,47 @@ func scale_image(width: int, height: int, interpolation: int) -> void:
 			var cel := f.cels[i]
 			if not cel is PixelCel:
 				continue
-			var sprite := Image.new()
-			sprite.copy_from(cel.get_image())
-			if interpolation == Interpolation.SCALE3X:
-				var times := Vector2i(
-					ceili(width / (3.0 * sprite.get_width())),
-					ceili(height / (3.0 * sprite.get_height()))
-				)
-				for _j in range(maxi(times.x, times.y)):
-					sprite.copy_from(scale_3x(sprite))
-				sprite.resize(width, height, Image.INTERPOLATE_NEAREST)
-			elif interpolation == Interpolation.CLEANEDGE:
-				var gen := ShaderImageEffect.new()
-				gen.generate_image(sprite, clean_edge_shader, {}, Vector2i(width, height))
-			elif interpolation == Interpolation.OMNISCALE and omniscale_shader:
-				var gen := ShaderImageEffect.new()
-				gen.generate_image(sprite, omniscale_shader, {}, Vector2i(width, height))
-			else:
-				sprite.resize(width, height, interpolation)
-			redo_data[cel.image] = sprite.data
-			undo_data[cel.image] = cel.image.data
+			var cel_image := (cel as PixelCel).get_image()
+			var sprite := _resize_image(cel_image, width, height, interpolation) as ImageExtended
+			sprite.add_data_to_dictionary(redo_data, cel_image)
+			cel_image.add_data_to_dictionary(undo_data)
 
 	general_do_and_undo_scale(width, height, redo_data, undo_data)
 
 
+func _resize_image(
+	image: Image, width: int, height: int, interpolation: Image.Interpolation
+) -> Image:
+	var new_image: Image
+	if image is ImageExtended:
+		new_image = ImageExtended.new()
+		new_image.is_indexed = image.is_indexed
+		new_image.copy_from(image)
+		new_image.select_palette("", false)
+	else:
+		new_image = Image.new()
+		new_image.copy_from(image)
+	if interpolation == Interpolation.SCALE3X:
+		var times := Vector2i(
+			ceili(width / (3.0 * new_image.get_width())),
+			ceili(height / (3.0 * new_image.get_height()))
+		)
+		for _j in range(maxi(times.x, times.y)):
+			new_image.copy_from(scale_3x(new_image))
+		new_image.resize(width, height, Image.INTERPOLATE_NEAREST)
+	elif interpolation == Interpolation.CLEANEDGE:
+		var gen := ShaderImageEffect.new()
+		gen.generate_image(new_image, clean_edge_shader, {}, Vector2i(width, height), false)
+	elif interpolation == Interpolation.OMNISCALE and omniscale_shader:
+		var gen := ShaderImageEffect.new()
+		gen.generate_image(new_image, omniscale_shader, {}, Vector2i(width, height), false)
+	else:
+		new_image.resize(width, height, interpolation)
+	if new_image is ImageExtended:
+		new_image.on_size_changed()
+	return new_image
+
+
 ## Sets the size of the project to be the same as the size of the active selection.
 func crop_to_selection() -> void:
 	if not Global.current_project.has_selection:
@@ -577,13 +601,13 @@ func crop_to_selection() -> void:
 	Global.canvas.selection.transform_content_confirm()
 	var rect: Rect2i = Global.canvas.selection.big_bounding_rectangle
 	# Loop through all the cels to crop them
-	for f in Global.current_project.frames:
-		for cel in f.cels:
-			if not cel is PixelCel:
-				continue
-			var sprite := cel.get_image().get_region(rect)
-			redo_data[cel.image] = sprite.data
-			undo_data[cel.image] = cel.image.data
+	for cel in Global.current_project.get_all_pixel_cels():
+		var cel_image := cel.get_image()
+		var tmp_cropped := cel_image.get_region(rect)
+		var cropped := ImageExtended.new()
+		cropped.copy_from_custom(tmp_cropped, cel_image.is_indexed)
+		cropped.add_data_to_dictionary(redo_data, cel_image)
+		cel_image.add_data_to_dictionary(undo_data)
 
 	general_do_and_undo_scale(rect.size.x, rect.size.y, redo_data, undo_data)
 
@@ -615,13 +639,13 @@ func crop_to_content() -> void:
 	var redo_data := {}
 	var undo_data := {}
 	# Loop through all the cels to trim them
-	for f in Global.current_project.frames:
-		for cel in f.cels:
-			if not cel is PixelCel:
-				continue
-			var sprite := cel.get_image().get_region(used_rect)
-			redo_data[cel.image] = sprite.data
-			undo_data[cel.image] = cel.image.data
+	for cel in Global.current_project.get_all_pixel_cels():
+		var cel_image := cel.get_image()
+		var tmp_cropped := cel_image.get_region(used_rect)
+		var cropped := ImageExtended.new()
+		cropped.copy_from_custom(tmp_cropped, cel_image.is_indexed)
+		cropped.add_data_to_dictionary(redo_data, cel_image)
+		cel_image.add_data_to_dictionary(undo_data)
 
 	general_do_and_undo_scale(width, height, redo_data, undo_data)
 
@@ -629,18 +653,17 @@ func crop_to_content() -> void:
 func resize_canvas(width: int, height: int, offset_x: int, offset_y: int) -> void:
 	var redo_data := {}
 	var undo_data := {}
-	for f in Global.current_project.frames:
-		for cel in f.cels:
-			if not cel is PixelCel:
-				continue
-			var sprite := Image.create(width, height, false, Image.FORMAT_RGBA8)
-			sprite.blend_rect(
-				cel.get_image(),
-				Rect2i(Vector2i.ZERO, Global.current_project.size),
-				Vector2i(offset_x, offset_y)
+	for cel in Global.current_project.get_all_pixel_cels():
+		var cel_image := cel.get_image()
+		var resized := ImageExtended.create_custom(
+			width, height, cel_image.has_mipmaps(), cel_image.get_format(), cel_image.is_indexed
 		)
-			redo_data[cel.image] = sprite.data
-			undo_data[cel.image] = cel.image.data
+		resized.blend_rect(
+			cel_image, Rect2i(Vector2i.ZERO, cel_image.get_size()), Vector2i(offset_x, offset_y)
+		)
+		resized.convert_rgb_to_indexed()
+		resized.add_data_to_dictionary(redo_data, cel_image)
+		cel_image.add_data_to_dictionary(undo_data)
 
 	general_do_and_undo_scale(width, height, redo_data, undo_data)
 

src/Autoload/Export.gd

@@ -161,7 +161,7 @@ func cache_blended_frames(project := Global.current_project) -> void:
 	blended_frames.clear()
 	var frames := _calculate_frames(project)
 	for frame in frames:
-		var image := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+		var image := project.new_empty_image()
 		_blend_layers(image, frame)
 		blended_frames[frame] = image
 
@@ -208,7 +208,7 @@ func process_spritesheet(project := Global.current_project) -> void:
 			spritesheet_columns = temp
 	var width := project.size.x * spritesheet_columns
 	var height := project.size.y * spritesheet_rows
-	var whole_image := Image.create(width, height, false, Image.FORMAT_RGBA8)
+	var whole_image := Image.create(width, height, false, project.get_image_format())
 	var origin := Vector2i.ZERO
 	var hh := 0
 	var vv := 0
@@ -287,10 +287,10 @@ func process_animation(project := Global.current_project) -> void:
 					ProcessedImage.new(image, project.frames.find(frame), duration)
 				)
 		else:
-			var image := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+			var image := project.new_empty_image()
 			image.copy_from(blended_frames[frame])
 			if erase_unselected_area and project.has_selection:
-				var crop := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+				var crop := project.new_empty_image()
 				var selection_image = project.selection_map.return_cropped_copy(project.size)
 				crop.blit_rect_mask(
 					image, selection_image, Rect2i(Vector2i.ZERO, image.get_size()), Vector2i.ZERO

src/Autoload/Global.gd

@@ -46,6 +46,7 @@ enum WindowMenu { WINDOW_OPACITY, PANELS, LAYOUTS, MOVABLE_PANELS, ZEN_MODE, FUL
 ## Enumeration of items present in the Image Menu.
 enum ImageMenu {
 	PROJECT_PROPERTIES,
+	COLOR_MODE,
 	RESIZE_CANVAS,
 	SCALE_IMAGE,
 	CROP_TO_SELECTION,
@@ -1113,8 +1114,17 @@ func undo_redo_compress_images(
 func undo_redo_draw_op(
 	image: Image, new_size: Vector2i, compressed_image_data: PackedByteArray, buffer_size: int
 ) -> void:
+	if image is ImageExtended and image.is_indexed:
+		# If using indexed mode,
+		# just convert the indices to RGB instead of setting the image data directly.
+		if image.get_size() != new_size:
+			image.crop(new_size.x, new_size.y)
+		image.convert_indexed_to_rgb()
+	else:
 		var decompressed := compressed_image_data.decompress(buffer_size)
-	image.set_data(new_size.x, new_size.y, image.has_mipmaps(), image.get_format(), decompressed)
+		image.set_data(
+			new_size.x, new_size.y, image.has_mipmaps(), image.get_format(), decompressed
+		)
 
 
 ## This method is used to write project setting overrides to the override.cfg file, located

src/Autoload/OpenSave.gd

@@ -150,7 +150,7 @@ func handle_loading_aimg(path: String, frames: Array) -> void:
 		if not frames_agree:
 			frame.duration = aimg_frame.duration * project.fps
 		var content := aimg_frame.content
-		content.convert(Image.FORMAT_RGBA8)
+		content.convert(project.get_image_format())
 		frame.cels.append(PixelCel.new(content, 1))
 		project.frames.append(frame)
 
@@ -389,18 +389,23 @@ func save_pxo_file(
 	var frame_index := 1
 	for frame in project.frames:
 		if not autosave and include_blended:
-			var blended := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+			var blended := project.new_empty_image()
 			DrawingAlgos.blend_layers(blended, frame, Vector2i.ZERO, project)
 			zip_packer.start_file("image_data/final_images/%s" % frame_index)
 			zip_packer.write_file(blended.get_data())
 			zip_packer.close_file()
 		var cel_index := 1
 		for cel in frame.cels:
-			var cel_image := cel.get_image()
+			var cel_image := cel.get_image() as ImageExtended
 			if is_instance_valid(cel_image) and cel is PixelCel:
 				zip_packer.start_file("image_data/frames/%s/layer_%s" % [frame_index, cel_index])
 				zip_packer.write_file(cel_image.get_data())
 				zip_packer.close_file()
+				zip_packer.start_file(
+					"image_data/frames/%s/indices_layer_%s" % [frame_index, cel_index]
+				)
+				zip_packer.write_file(cel_image.indices_image.get_data())
+				zip_packer.close_file()
 			cel_index += 1
 		frame_index += 1
 	var brush_index := 0
@@ -457,12 +462,13 @@ func save_pxo_file(
 
 func open_image_as_new_tab(path: String, image: Image) -> void:
 	var project := Project.new([], path.get_file(), image.get_size())
-	project.layers.append(PixelLayer.new(project))
+	var layer := PixelLayer.new(project)
+	project.layers.append(layer)
 	Global.projects.append(project)
 
 	var frame := Frame.new()
-	image.convert(Image.FORMAT_RGBA8)
-	frame.cels.append(PixelCel.new(image, 1))
+	image.convert(project.get_image_format())
+	frame.cels.append(layer.new_cel_from_image(image))
 
 	project.frames.append(frame)
 	set_new_imported_tab(project, path)
@@ -475,15 +481,18 @@ func open_image_as_spritesheet_tab_smart(
 		frame_size = image.get_size()
 		sliced_rects.append(Rect2i(Vector2i.ZERO, frame_size))
 	var project := Project.new([], path.get_file(), frame_size)
-	project.layers.append(PixelLayer.new(project))
+	var layer := PixelLayer.new(project)
+	project.layers.append(layer)
 	Global.projects.append(project)
 	for rect in sliced_rects:
 		var offset: Vector2 = (0.5 * (frame_size - rect.size)).floor()
 		var frame := Frame.new()
-		var cropped_image := Image.create(frame_size.x, frame_size.y, false, Image.FORMAT_RGBA8)
-		image.convert(Image.FORMAT_RGBA8)
+		var cropped_image := Image.create(
+			frame_size.x, frame_size.y, false, project.get_image_format()
+		)
+		image.convert(project.get_image_format())
 		cropped_image.blit_rect(image, rect, offset)
-		frame.cels.append(PixelCel.new(cropped_image, 1))
+		frame.cels.append(layer.new_cel_from_image(cropped_image))
 		project.frames.append(frame)
 	set_new_imported_tab(project, path)
 
@@ -494,7 +503,8 @@ func open_image_as_spritesheet_tab(path: String, image: Image, horiz: int, vert:
 	var frame_width := image.get_size().x / horiz
 	var frame_height := image.get_size().y / vert
 	var project := Project.new([], path.get_file(), Vector2(frame_width, frame_height))
-	project.layers.append(PixelLayer.new(project))
+	var layer := PixelLayer.new(project)
+	project.layers.append(layer)
 	Global.projects.append(project)
 	for yy in range(vert):
 		for xx in range(horiz):
@@ -503,8 +513,8 @@ func open_image_as_spritesheet_tab(path: String, image: Image, horiz: int, vert:
 				Rect2i(frame_width * xx, frame_height * yy, frame_width, frame_height)
 			)
 			project.size = cropped_image.get_size()
-			cropped_image.convert(Image.FORMAT_RGBA8)
-			frame.cels.append(PixelCel.new(cropped_image, 1))
+			cropped_image.convert(project.get_image_format())
+			frame.cels.append(layer.new_cel_from_image(cropped_image))
 			project.frames.append(frame)
 	set_new_imported_tab(project, path)
 
@@ -562,12 +572,12 @@ func open_image_as_spritesheet_layer_smart(
 		if f >= start_frame and f < (start_frame + sliced_rects.size()):
 			# Slice spritesheet
 			var offset: Vector2 = (0.5 * (frame_size - sliced_rects[f - start_frame].size)).floor()
-			image.convert(Image.FORMAT_RGBA8)
+			image.convert(project.get_image_format())
 			var cropped_image := Image.create(
-				project_width, project_height, false, Image.FORMAT_RGBA8
+				project_width, project_height, false, project.get_image_format()
 			)
 			cropped_image.blit_rect(image, sliced_rects[f - start_frame], offset)
-			cels.append(PixelCel.new(cropped_image))
+			cels.append(layer.new_cel_from_image(cropped_image))
 		else:
 			cels.append(layer.new_empty_cel())
 
@@ -644,16 +654,16 @@ func open_image_as_spritesheet_layer(
 			# Slice spritesheet
 			var xx := (f - start_frame) % horizontal
 			var yy := (f - start_frame) / horizontal
-			image.convert(Image.FORMAT_RGBA8)
+			image.convert(project.get_image_format())
 			var cropped_image := Image.create(
-				project_width, project_height, false, Image.FORMAT_RGBA8
+				project_width, project_height, false, project.get_image_format()
 			)
 			cropped_image.blit_rect(
 				image,
 				Rect2i(frame_width * xx, frame_height * yy, frame_width, frame_height),
 				Vector2i.ZERO
 			)
-			cels.append(PixelCel.new(cropped_image))
+			cels.append(layer.new_cel_from_image(cropped_image))
 		else:
 			cels.append(layer.new_empty_cel())
 
@@ -687,12 +697,18 @@ func open_image_at_cel(image: Image, layer_index := 0, frame_index := 0) -> void
 	var cel := project.frames[frame_index].cels[layer_index]
 	if not cel is PixelCel:
 		return
-	image.convert(Image.FORMAT_RGBA8)
-	var cel_image := Image.create(project_width, project_height, false, Image.FORMAT_RGBA8)
-	cel_image.blit_rect(image, Rect2i(Vector2i.ZERO, image.get_size()), Vector2i.ZERO)
-	Global.undo_redo_compress_images(
-		{cel.image: cel_image.data}, {cel.image: cel.image.data}, project
+	image.convert(project.get_image_format())
+	var cel_image := (cel as PixelCel).get_image()
+	var new_cel_image := ImageExtended.create_custom(
+		project_width, project_height, false, project.get_image_format(), cel_image.is_indexed
 	)
+	new_cel_image.blit_rect(image, Rect2i(Vector2i.ZERO, image.get_size()), Vector2i.ZERO)
+	new_cel_image.convert_rgb_to_indexed()
+	var redo_data := {}
+	new_cel_image.add_data_to_dictionary(redo_data, cel_image)
+	var undo_data := {}
+	cel_image.add_data_to_dictionary(undo_data)
+	Global.undo_redo_compress_images(redo_data, undo_data, project)
 
 	project.undo_redo.add_do_property(project, "selected_cels", [])
 	project.undo_redo.add_do_method(project.change_cel.bind(frame_index, layer_index))
@@ -716,11 +732,14 @@ func open_image_as_new_frame(
 
 	var frame := Frame.new()
 	for i in project.layers.size():
-		if i == layer_index:
-			image.convert(Image.FORMAT_RGBA8)
-			var cel_image := Image.create(project_width, project_height, false, Image.FORMAT_RGBA8)
+		var layer := project.layers[i]
+		if i == layer_index and layer is PixelLayer:
+			image.convert(project.get_image_format())
+			var cel_image := Image.create(
+				project_width, project_height, false, project.get_image_format()
+			)
 			cel_image.blit_rect(image, Rect2i(Vector2i.ZERO, image.get_size()), Vector2i.ZERO)
-			frame.cels.append(PixelCel.new(cel_image, 1))
+			frame.cels.append(layer.new_cel_from_image(cel_image))
 		else:
 			frame.cels.append(project.layers[i].new_empty_cel())
 	if not undo:
@@ -753,10 +772,12 @@ func open_image_as_new_layer(image: Image, file_name: String, frame_index := 0)
 	Global.current_project.undo_redo.create_action("Add Layer")
 	for i in project.frames.size():
 		if i == frame_index:
-			image.convert(Image.FORMAT_RGBA8)
-			var cel_image := Image.create(project_width, project_height, false, Image.FORMAT_RGBA8)
+			image.convert(project.get_image_format())
+			var cel_image := Image.create(
+				project_width, project_height, false, project.get_image_format()
+			)
 			cel_image.blit_rect(image, Rect2i(Vector2i.ZERO, image.get_size()), Vector2i.ZERO)
-			cels.append(PixelCel.new(cel_image, 1))
+			cels.append(layer.new_cel_from_image(cel_image))
 		else:
 			cels.append(layer.new_empty_cel())
 

src/Classes/Cels/GroupCel.gd

@@ -10,9 +10,7 @@ func _init(_opacity := 1.0) -> void:
 
 
 func get_image() -> Image:
-	var image := Image.create(
-		Global.current_project.size.x, Global.current_project.size.y, false, Image.FORMAT_RGBA8
-	)
+	var image := Global.current_project.new_empty_image()
 	return image
 
 

src/Classes/Cels/PixelCel.gd

@@ -4,17 +4,17 @@ extends BaseCel
 ## The term "cel" comes from "celluloid" (https://en.wikipedia.org/wiki/Cel).
 
 ## This variable is where the image data of the cel are.
-var image: Image:
+var image: ImageExtended:
 	set = image_changed
 
 
-func _init(_image := Image.new(), _opacity := 1.0) -> void:
+func _init(_image: ImageExtended, _opacity := 1.0) -> void:
 	image_texture = ImageTexture.new()
 	image = _image  # Set image and call setter
 	opacity = _opacity
 
 
-func image_changed(value: Image) -> void:
+func image_changed(value: ImageExtended) -> void:
 	image = value
 	if not image.is_empty() and is_instance_valid(image_texture):
 		image_texture.set_image(image)
@@ -48,7 +48,7 @@ func copy_content():
 	return copy_image
 
 
-func get_image() -> Image:
+func get_image() -> ImageExtended:
 	return image
 
 

src/Classes/Drawers.gd

@@ -27,12 +27,12 @@ class ColorOp:
 
 
 class SimpleDrawer:
-	func set_pixel(image: Image, position: Vector2i, color: Color, op: ColorOp) -> void:
+	func set_pixel(image: ImageExtended, position: Vector2i, color: Color, op: ColorOp) -> void:
 		var color_old := image.get_pixelv(position)
 		var color_str := color.to_html()
 		var color_new := op.process(Color(color_str), color_old)
 		if not color_new.is_equal_approx(color_old):
-			image.set_pixelv(position, color_new)
+			image.set_pixelv_custom(position, color_new)
 
 
 class PixelPerfectDrawer:
@@ -43,11 +43,11 @@ class PixelPerfectDrawer:
 	func reset() -> void:
 		last_pixels = [null, null]
 
-	func set_pixel(image: Image, position: Vector2i, color: Color, op: ColorOp) -> void:
+	func set_pixel(image: ImageExtended, position: Vector2i, color: Color, op: ColorOp) -> void:
 		var color_old := image.get_pixelv(position)
 		var color_str := color.to_html()
 		last_pixels.push_back([position, color_old])
-		image.set_pixelv(position, op.process(Color(color_str), color_old))
+		image.set_pixelv_custom(position, op.process(Color(color_str), color_old))
 
 		var corner = last_pixels.pop_front()
 		var neighbour = last_pixels[0]
@@ -56,7 +56,7 @@ class PixelPerfectDrawer:
 			return
 
 		if position - corner[0] in CORNERS and position - neighbour[0] in NEIGHBOURS:
-			image.set_pixel(neighbour[0].x, neighbour[0].y, neighbour[1])
+			image.set_pixel_custom(neighbour[0].x, neighbour[0].y, neighbour[1])
 			last_pixels[0] = corner
 
 

src/Classes/ImageEffect.gd

@@ -170,12 +170,12 @@ func _get_undo_data(project: Project) -> Dictionary:
 	var data := {}
 	var images := _get_selected_draw_images(project)
 	for image in images:
-		data[image] = image.data
+		image.add_data_to_dictionary(data)
 	return data
 
 
-func _get_selected_draw_images(project: Project) -> Array[Image]:
-	var images: Array[Image] = []
+func _get_selected_draw_images(project: Project) -> Array[ImageExtended]:
+	var images: Array[ImageExtended] = []
 	if affect == SELECTED_CELS:
 		for cel_index in project.selected_cels:
 			var cel: BaseCel = project.frames[cel_index[0]].cels[cel_index[1]]

src/Classes/ImageExtended.gd

@@ -0,0 +1,176 @@
+class_name ImageExtended
+extends Image
+
+## A custom [Image] class that implements support for indexed mode.
+## Before implementing indexed mode, we just used the [Image] class.
+## In indexed mode, each pixel is assigned to a number that references a palette color.
+## This essentially means that the colors of the image are restricted to a specific palette,
+## and they will automatically get updated when you make changes to that palette, or when
+## you switch to a different one.
+
+const TRANSPARENT := Color(0)
+const SET_INDICES := preload("res://src/Shaders/SetIndices.gdshader")
+const INDEXED_TO_RGB := preload("res://src/Shaders/IndexedToRGB.gdshader")
+
+## If [code]true[/code], the image uses indexed mode.
+var is_indexed := false
+## The [Palette] the image is currently using for indexed mode.
+var current_palette := Palettes.current_palette
+## An [Image] that contains the index of each pixel of the main image for indexed mode.
+## The indices are stored in the red channel of this image, by diving each index by 255.
+## This means that there can be a maximum index size of 255. 0 means that the pixel is transparent.
+var indices_image := Image.create_empty(1, 1, false, Image.FORMAT_R8)
+## A [PackedColorArray] containing all of the colors of the [member current_palette].
+var palette := PackedColorArray()
+
+
+func _init() -> void:
+	indices_image.fill(TRANSPARENT)
+	Palettes.palette_selected.connect(select_palette)
+
+
+## Equivalent of [method Image.create_empty], but returns [ImageExtended] instead.
+## If [param _is_indexed] is [code]true[/code], the image that is being returned uses indexed mode.
+static func create_custom(
+	width: int, height: int, mipmaps: bool, format: Image.Format, _is_indexed := false
+) -> ImageExtended:
+	var new_image := ImageExtended.new()
+	new_image.crop(width, height)
+	if mipmaps:
+		new_image.generate_mipmaps()
+	new_image.convert(format)
+	new_image.fill(TRANSPARENT)
+	new_image.is_indexed = _is_indexed
+	if new_image.is_indexed:
+		new_image.resize_indices()
+		new_image.select_palette("", false)
+	return new_image
+
+
+## Equivalent of [method Image.copy_from], but also handles the logic necessary for indexed mode.
+## If [param _is_indexed] is [code]true[/code], the image is set to be using indexed mode.
+func copy_from_custom(image: Image, indexed := is_indexed) -> void:
+	is_indexed = indexed
+	copy_from(image)
+	if is_indexed:
+		resize_indices()
+		select_palette("", false)
+		convert_rgb_to_indexed()
+
+
+## Selects a new palette to use in indexed mode.
+func select_palette(_name: String, convert_to_rgb := true) -> void:
+	current_palette = Palettes.current_palette
+	if not is_instance_valid(current_palette) or not is_indexed:
+		return
+	update_palette()
+	if not current_palette.data_changed.is_connected(update_palette):
+		current_palette.data_changed.connect(update_palette)
+	if not current_palette.data_changed.is_connected(convert_indexed_to_rgb):
+		current_palette.data_changed.connect(convert_indexed_to_rgb)
+	if convert_to_rgb:
+		convert_indexed_to_rgb()
+
+
+## Updates [member palette] to contain the colors of [member current_palette].
+func update_palette() -> void:
+	if palette.size() != current_palette.colors.size():
+		palette.resize(current_palette.colors.size())
+	for i in current_palette.colors:
+		palette[i] = current_palette.colors[i].color
+
+
+## Displays the actual RGBA values of each pixel in the image from indexed mode.
+func convert_indexed_to_rgb() -> void:
+	if not is_indexed:
+		return
+	var palette_image := Palettes.current_palette.convert_to_image()
+	var palette_texture := ImageTexture.create_from_image(palette_image)
+	var shader_image_effect := ShaderImageEffect.new()
+	var indices_texture := ImageTexture.create_from_image(indices_image)
+	var params := {"palette_texture": palette_texture, "indices_texture": indices_texture}
+	shader_image_effect.generate_image(self, INDEXED_TO_RGB, params, get_size(), false)
+	Global.canvas.queue_redraw()
+
+
+## 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:
+		return
+	var palette_image := Palettes.current_palette.convert_to_image()
+	var palette_texture := ImageTexture.create_from_image(palette_image)
+	var params := {
+		"palette_texture": palette_texture, "rgb_texture": ImageTexture.create_from_image(self)
+	}
+	var shader_image_effect := ShaderImageEffect.new()
+	shader_image_effect.generate_image(
+		indices_image, SET_INDICES, params, indices_image.get_size(), false
+	)
+	convert_indexed_to_rgb()
+
+
+## Resizes indices and calls [method convert_rgb_to_indexed] when the image's size changes
+## and indexed mode is enabled.
+func on_size_changed() -> void:
+	if is_indexed:
+		resize_indices()
+		convert_rgb_to_indexed()
+
+
+## Resizes [indices_image] to the image's size.
+func resize_indices() -> void:
+	indices_image.crop(get_width(), get_height())
+
+
+## Equivalent of [method Image.set_pixel_custom],
+## but also handles the logic necessary for indexed mode.
+func set_pixel_custom(x: int, y: int, color: Color) -> void:
+	set_pixelv_custom(Vector2i(x, y), color)
+
+
+## Equivalent of [method Image.set_pixelv_custom],
+## but also handles the logic necessary for indexed mode.
+func set_pixelv_custom(point: Vector2i, color: Color) -> void:
+	var new_color := color
+	if is_indexed:
+		var color_to_fill := TRANSPARENT
+		var color_index := 0
+		if not color.is_equal_approx(TRANSPARENT):
+			if palette.has(color):
+				color_index = palette.find(color)
+			else:  # Find the most similar color
+				var smaller_distance := color_distance(color, palette[0])
+				for i in palette.size():
+					var swatch := palette[i]
+					if is_zero_approx(swatch.a):  # Skip transparent colors
+						continue
+					var dist := color_distance(color, swatch)
+					if dist < smaller_distance:
+						smaller_distance = dist
+						color_index = i
+			indices_image.set_pixelv(point, Color((color_index + 1) / 255.0, 0, 0, 0))
+			color_to_fill = palette[color_index]
+			new_color = color_to_fill
+		else:
+			indices_image.set_pixelv(point, TRANSPARENT)
+			new_color = TRANSPARENT
+	set_pixelv(point, new_color)
+
+
+## Finds the distance between colors [param c1] and [param c2].
+func color_distance(c1: Color, c2: Color) -> float:
+	var v1 := Vector4(c1.r, c1.g, c1.b, c1.a)
+	var v2 := Vector4(c2.r, c2.g, c2.b, c2.a)
+	return v2.distance_to(v1)
+
+
+## Adds image data to a [param dict] [Dictionary]. Used for undo/redo.
+func add_data_to_dictionary(dict: Dictionary, other_image: ImageExtended = null) -> void:
+	# The order matters! Setting self's data first would make undo/redo appear to work incorrectly.
+	if is_instance_valid(other_image):
+		dict[other_image.indices_image] = indices_image.data
+		dict[other_image] = data
+	else:
+		dict[indices_image] = indices_image.data
+		dict[self] = data

src/Classes/Layers/BaseLayer.gd

@@ -218,11 +218,16 @@ func link_cel(cel: BaseCel, link_set = null) -> void:
 ## This method is not destructive as it does NOT change the data of the image,
 ## it just returns a copy.
 func display_effects(cel: BaseCel, image_override: Image = null) -> Image:
-	var image := Image.new()
+	var image := ImageExtended.new()
 	if is_instance_valid(image_override):
-		image.copy_from(image_override)
+		if image_override is ImageExtended:
+			image.is_indexed = image_override.is_indexed
+		image.copy_from_custom(image_override)
 	else:
-		image.copy_from(cel.get_image())
+		var cel_image := cel.get_image()
+		if cel_image is ImageExtended:
+			image.is_indexed = cel_image.is_indexed
+		image.copy_from_custom(cel_image)
 	if not effects_enabled:
 		return image
 	var image_size := image.get_size()

src/Classes/Layers/GroupLayer.gd

@@ -13,7 +13,9 @@ func _init(_project: Project, _name := "") -> void:
 
 ## Blends all of the images of children layer of the group layer into a single image.
 func blend_children(frame: Frame, origin := Vector2i.ZERO, apply_effects := true) -> Image:
-	var image := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+	var image := ImageExtended.create_custom(
+		project.size.x, project.size.y, false, project.get_image_format(), project.is_indexed()
+	)
 	var children := get_children(false)
 	if children.size() <= 0:
 		return image
@@ -66,7 +68,7 @@ func blend_children(frame: Frame, origin := Vector2i.ZERO, apply_effects := true
 
 
 func _include_child_in_blending(
-	image: Image,
+	image: ImageExtended,
 	layer: BaseLayer,
 	frame: Frame,
 	textures: Array[Image],
@@ -100,7 +102,7 @@ func _include_child_in_blending(
 ## Gets called recursively if the child group has children groups of its own,
 ## and they are also set to pass through mode.
 func _blend_child_group(
-	image: Image,
+	image: ImageExtended,
 	layer: BaseLayer,
 	frame: Frame,
 	textures: Array[Image],

src/Classes/Layers/PixelLayer.gd

@@ -28,9 +28,19 @@ func get_layer_type() -> int:
 
 
 func new_empty_cel() -> BaseCel:
-	var image := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+	var format := project.get_image_format()
+	var is_indexed := project.is_indexed()
+	var image := ImageExtended.create_custom(
+		project.size.x, project.size.y, false, format, is_indexed
+	)
 	return PixelCel.new(image)
 
 
+func new_cel_from_image(image: Image) -> PixelCel:
+	var pixelorama_image := ImageExtended.new()
+	pixelorama_image.copy_from_custom(image, project.is_indexed())
+	return PixelCel.new(pixelorama_image)
+
+
 func can_layer_get_drawn() -> bool:
 	return is_visible_in_hierarchy() && !is_locked_in_hierarchy()

src/Classes/Project.gd

@@ -9,6 +9,8 @@ signal about_to_deserialize(dict: Dictionary)
 signal resized
 signal timeline_updated
 
+const INDEXED_MODE := Image.FORMAT_MAX + 1
+
 var name := "":
 	set(value):
 		name = value
@@ -21,6 +23,17 @@ var undo_redo := UndoRedo.new()
 var tiles: Tiles
 var undos := 0  ## The number of times we added undo properties
 var can_undo := true
+var color_mode: int = Image.FORMAT_RGBA8:
+	set(value):
+		if color_mode != value:
+			color_mode = value
+			for cel in get_all_pixel_cels():
+				var image := cel.get_image()
+				image.is_indexed = is_indexed()
+				if image.is_indexed:
+					image.resize_indices()
+					image.select_palette("", false)
+					image.convert_rgb_to_indexed()
 var fill_color := Color(0)
 var has_changed := false:
 	set(value):
@@ -176,11 +189,26 @@ func new_empty_frame() -> Frame:
 	return frame
 
 
+## Returns a new [Image] of size [member size] and format [method get_image_format].
+func new_empty_image() -> Image:
+	return Image.create(size.x, size.y, false, get_image_format())
+
+
 ## Returns the currently selected [BaseCel].
 func get_current_cel() -> BaseCel:
 	return frames[current_frame].cels[current_layer]
 
 
+func get_image_format() -> Image.Format:
+	if color_mode == INDEXED_MODE:
+		return Image.FORMAT_RGBA8
+	return color_mode
+
+
+func is_indexed() -> bool:
+	return color_mode == INDEXED_MODE
+
+
 func selection_map_changed() -> void:
 	var image_texture: ImageTexture
 	has_selection = !selection_map.is_invisible()
@@ -255,6 +283,7 @@ func serialize() -> Dictionary:
 		"pxo_version": ProjectSettings.get_setting("application/config/Pxo_Version"),
 		"size_x": size.x,
 		"size_y": size.y,
+		"color_mode": color_mode,
 		"tile_mode_x_basis_x": tiles.x_basis.x,
 		"tile_mode_x_basis_y": tiles.x_basis.y,
 		"tile_mode_y_basis_x": tiles.y_basis.x,
@@ -288,6 +317,7 @@ func deserialize(dict: Dictionary, zip_reader: ZIPReader = null, file: FileAcces
 		size.y = dict.size_y
 		tiles.tile_size = size
 		selection_map.crop(size.x, size.y)
+	color_mode = dict.get("color_mode", color_mode)
 	if dict.has("tile_mode_x_basis_x") and dict.has("tile_mode_x_basis_y"):
 		tiles.x_basis.x = dict.tile_mode_x_basis_x
 		tiles.x_basis.y = dict.tile_mode_x_basis_y
@@ -311,20 +341,33 @@ func deserialize(dict: Dictionary, zip_reader: ZIPReader = null, file: FileAcces
 			for cel in frame.cels:
 				match int(dict.layers[cel_i].get("type", Global.LayerTypes.PIXEL)):
 					Global.LayerTypes.PIXEL:
-						var image := Image.new()
+						var image: Image
+						var indices_data := PackedByteArray()
 						if is_instance_valid(zip_reader):  # For pxo files saved in 1.0+
-							var image_data := zip_reader.read_file(
-								"image_data/frames/%s/layer_%s" % [frame_i + 1, cel_i + 1]
-							)
+							var path := "image_data/frames/%s/layer_%s" % [frame_i + 1, cel_i + 1]
+							var image_data := zip_reader.read_file(path)
 							image = Image.create_from_data(
-								size.x, size.y, false, Image.FORMAT_RGBA8, image_data
+								size.x, size.y, false, get_image_format(), image_data
 							)
+							var indices_path := (
+								"image_data/frames/%s/indices_layer_%s" % [frame_i + 1, cel_i + 1]
+							)
+							if zip_reader.file_exists(indices_path):
+								indices_data = zip_reader.read_file(indices_path)
 						elif is_instance_valid(file):  # For pxo files saved in 0.x
 							var buffer := file.get_buffer(size.x * size.y * 4)
 							image = Image.create_from_data(
-								size.x, size.y, false, Image.FORMAT_RGBA8, buffer
+								size.x, size.y, false, get_image_format(), buffer
 							)
-						cels.append(PixelCel.new(image))
+						var pixelorama_image := ImageExtended.new()
+						pixelorama_image.is_indexed = is_indexed()
+						if not indices_data.is_empty() and is_indexed():
+							pixelorama_image.indices_image = Image.create_from_data(
+								size.x, size.y, false, Image.FORMAT_R8, indices_data
+							)
+						pixelorama_image.copy_from(image)
+						pixelorama_image.select_palette("", true)
+						cels.append(PixelCel.new(pixelorama_image))
 					Global.LayerTypes.GROUP:
 						cels.append(GroupCel.new())
 					Global.LayerTypes.THREE_D:
@@ -559,6 +602,16 @@ func find_first_drawable_cel(frame := frames[current_frame]) -> BaseCel:
 	return result
 
 
+## Returns an [Array] of type [PixelCel] containing all of the pixel cels of the project.
+func get_all_pixel_cels() -> Array[PixelCel]:
+	var cels: Array[PixelCel]
+	for frame in frames:
+		for cel in frame.cels:
+			if cel is PixelCel:
+				cels.append(cel)
+	return cels
+
+
 ## Re-order layers to take each cel's z-index into account. If all z-indexes are 0,
 ## then the order of drawing is the same as the order of the layers itself.
 func order_layers(frame_index := current_frame) -> void:

src/Classes/ShaderImageEffect.gd

@@ -5,7 +5,9 @@ extends RefCounted
 signal done
 
 
-func generate_image(img: Image, shader: Shader, params: Dictionary, size: Vector2i) -> void:
+func generate_image(
+	img: Image, shader: Shader, params: Dictionary, size: Vector2i, respect_indexed := true
+) -> void:
 	# duplicate shader before modifying code to avoid affecting original resource
 	var resized_width := false
 	var resized_height := false
@@ -60,4 +62,6 @@ func generate_image(img: Image, shader: Shader, params: Dictionary, size: Vector
 		img.crop(img.get_width() - 1, img.get_height())
 	if resized_height:
 		img.crop(img.get_width(), img.get_height() - 1)
+	if img is ImageExtended and respect_indexed:
+		img.convert_rgb_to_indexed()
 	done.emit()

src/Shaders/Effects/Palettize.gdshader

@@ -3,6 +3,7 @@
 shader_type canvas_item;
 render_mode unshaded;
 
+#include "res://src/Shaders/FindPaletteColorIndex.gdshaderinc"
 uniform sampler2D palette_texture : filter_nearest;
 uniform sampler2D selection : filter_nearest;
 
@@ -10,18 +11,9 @@ vec4 swap_color(vec4 color) {
 	if (color.a <= 0.01) {
 		return color;
 	}
-	int color_index = 0;
+
 	int n_of_colors = textureSize(palette_texture, 0).x;
-	float smaller_distance = distance(color, texture(palette_texture, vec2(0.0)));
-	for (int i = 0; i <= n_of_colors; i++) {
-		vec2 uv = vec2(float(i) / float(n_of_colors), 0.0);
-		vec4 palette_color = texture(palette_texture, uv);
-		float dist = distance(color, palette_color);
-		if (dist < smaller_distance) {
-			smaller_distance = dist;
-			color_index = i;
-		}
-	}
+	int color_index = find_index(color, n_of_colors, palette_texture);
 	return texture(palette_texture, vec2(float(color_index) / float(n_of_colors), 0.0));
 }
 

src/Shaders/FindPaletteColorIndex.gdshaderinc

@@ -0,0 +1,14 @@
+int find_index(vec4 color, int n_of_colors, sampler2D palette_texture) {
+	int color_index = 0;
+	float smaller_distance = distance(color, texture(palette_texture, vec2(0.0)));
+	for (int i = 0; i <= n_of_colors; i++) {
+		vec2 uv = vec2(float(i) / float(n_of_colors), 0.0);
+		vec4 palette_color = texture(palette_texture, uv);
+		float dist = distance(color, palette_color);
+		if (dist < smaller_distance) {
+			smaller_distance = dist;
+			color_index = i;
+		}
+	}
+	return color_index;
+}

src/Shaders/IndexedToRGB.gdshader

@@ -0,0 +1,28 @@
+shader_type canvas_item;
+render_mode unshaded;
+
+const float EPSILON = 0.0001;
+
+uniform sampler2D palette_texture : filter_nearest;
+uniform sampler2D indices_texture : filter_nearest;
+
+void fragment() {
+	float index = texture(indices_texture, UV).r;
+	if (index <= EPSILON) { // If index is zero, make it transparent
+		COLOR = vec4(0.0);
+	}
+	else {
+		float n_of_colors = float(textureSize(palette_texture, 0).x);
+		index -= 1.0 / 255.0;
+		float index_normalized = ((index * 255.0)) / n_of_colors;
+		if (index_normalized + EPSILON < 1.0) {
+			COLOR = texture(palette_texture, vec2(index_normalized + EPSILON, 0.0));
+		}
+		else {
+			// If index is bigger than the size of the palette, make it transparent.
+			// This happens when switching to a palette, where the previous palette was bigger
+			// than the newer one, and the current index is out of bounds of the new one.
+			COLOR = vec4(0.0);
+		}
+	}
+}

src/Shaders/SetIndices.gdshader

@@ -0,0 +1,18 @@
+shader_type canvas_item;
+render_mode unshaded;
+
+#include "res://src/Shaders/FindPaletteColorIndex.gdshaderinc"
+uniform sampler2D rgb_texture : filter_nearest;
+uniform sampler2D palette_texture : filter_nearest;
+
+
+void fragment() {
+	vec4 color = texture(rgb_texture, UV);
+	if (color.a <= 0.01) {
+		COLOR.r = 0.0;
+	}
+	else {
+		int color_index = find_index(color, textureSize(palette_texture, 0).x, palette_texture);
+		COLOR.r = float(color_index + 1) / 255.0;
+	}
+}

src/Tools/BaseDraw.gd

@@ -35,7 +35,7 @@ var _line_polylines := []
 
 # Memorize some stuff when doing brush strokes
 var _stroke_project: Project
-var _stroke_images: Array[Image] = []
+var _stroke_images: Array[ImageExtended] = []
 var _is_mask_size_zero := true
 var _circle_tool_shortcut: Array[Vector2i]
 
@@ -730,8 +730,8 @@ func _get_undo_data() -> Dictionary:
 	for cel in cels:
 		if not cel is PixelCel:
 			continue
-		var image := cel.get_image()
-		data[image] = image.data
+		var image := (cel as PixelCel).get_image()
+		image.add_data_to_dictionary(data)
 	return data
 
 

src/Tools/BaseTool.gd

@@ -299,12 +299,12 @@ func _get_draw_rect() -> Rect2i:
 		return Rect2i(Vector2i.ZERO, Global.current_project.size)
 
 
-func _get_draw_image() -> Image:
+func _get_draw_image() -> ImageExtended:
 	return Global.current_project.get_current_cel().get_image()
 
 
-func _get_selected_draw_images() -> Array[Image]:
-	var images: Array[Image] = []
+func _get_selected_draw_images() -> Array[ImageExtended]:
+	var images: Array[ImageExtended] = []
 	var project := Global.current_project
 	for cel_index in project.selected_cels:
 		var cel: BaseCel = project.frames[cel_index[0]].cels[cel_index[1]]

src/Tools/DesignTools/Bucket.gd

@@ -220,7 +220,7 @@ func fill_in_color(pos: Vector2i) -> void:
 		if project.has_selection:
 			selection = project.selection_map.return_cropped_copy(project.size)
 		else:
-			selection = Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+			selection = project.new_empty_image()
 			selection.fill(Color(1, 1, 1, 1))
 
 		selection_tex = ImageTexture.create_from_image(selection)
@@ -263,7 +263,7 @@ func fill_in_selection() -> void:
 	var images := _get_selected_draw_images()
 	if _fill_with == FillWith.COLOR or _pattern == null:
 		if project.has_selection:
-			var filler := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+			var filler := project.new_empty_image()
 			filler.fill(tool_slot.color)
 			var rect: Rect2i = Global.canvas.selection.big_bounding_rectangle
 			var selection_map_copy := project.selection_map.return_cropped_copy(project.size)
@@ -284,7 +284,7 @@ func fill_in_selection() -> void:
 		if project.has_selection:
 			selection = project.selection_map.return_cropped_copy(project.size)
 		else:
-			selection = Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+			selection = project.new_empty_image()
 			selection.fill(Color(1, 1, 1, 1))
 
 		selection_tex = ImageTexture.create_from_image(selection)
@@ -461,7 +461,7 @@ func _compute_segments_for_image(
 					done = false
 
 
-func _color_segments(image: Image) -> void:
+func _color_segments(image: ImageExtended) -> void:
 	if _fill_with == FillWith.COLOR or _pattern == null:
 		# This is needed to ensure that the color used to fill is not wrong, due to float
 		# rounding issues.
@@ -472,7 +472,7 @@ func _color_segments(image: Image) -> void:
 			var p := _allegro_image_segments[c]
 			for px in range(p.left_position, p.right_position + 1):
 				# We don't have to check again whether the point being processed is within the bounds
-				image.set_pixel(px, p.y, color)
+				image.set_pixel_custom(px, p.y, color)
 	else:
 		# shortcircuit tests for patternfills
 		var pattern_size := _pattern.image.get_size()
@@ -484,11 +484,11 @@ func _color_segments(image: Image) -> void:
 				_set_pixel_pattern(image, px, p.y, pattern_size)
 
 
-func _set_pixel_pattern(image: Image, x: int, y: int, pattern_size: Vector2i) -> void:
+func _set_pixel_pattern(image: ImageExtended, x: int, y: int, pattern_size: Vector2i) -> void:
 	var px := (x + _offset_x) % pattern_size.x
 	var py := (y + _offset_y) % pattern_size.y
 	var pc := _pattern.image.get_pixel(px, py)
-	image.set_pixel(x, y, pc)
+	image.set_pixel_custom(x, y, pc)
 
 
 func commit_undo() -> void:
@@ -514,12 +514,12 @@ func _get_undo_data() -> Dictionary:
 	if Global.animation_timeline.animation_timer.is_stopped():
 		var images := _get_selected_draw_images()
 		for image in images:
-			data[image] = image.data
+			image.add_data_to_dictionary(data)
 	else:
 		for frame in Global.current_project.frames:
 			var cel := frame.cels[Global.current_project.current_layer]
 			if not cel is PixelCel:
 				continue
-			var image := cel.get_image()
-			data[image] = image.data
+			var image := (cel as PixelCel).get_image()
+			image.add_data_to_dictionary(data)
 	return data

src/Tools/DesignTools/CurveTool.gd

@@ -203,7 +203,7 @@ func _draw_shape() -> void:
 	commit_undo()
 
 
-func _draw_pixel(point: Vector2i, images: Array[Image]) -> void:
+func _draw_pixel(point: Vector2i, images: Array[ImageExtended]) -> void:
 	if Global.current_project.can_pixel_get_drawn(point):
 		for image in images:
 			_drawer.set_pixel(image, point, tool_slot.color)

src/Tools/DesignTools/Eraser.gd

@@ -122,6 +122,7 @@ func _draw_brush_image(image: Image, src_rect: Rect2i, dst: Vector2i) -> void:
 		var images := _get_selected_draw_images()
 		for draw_image in images:
 			draw_image.blit_rect_mask(_clear_image, image, src_rect, dst)
+			draw_image.convert_rgb_to_indexed()
 	else:
 		for xx in image.get_size().x:
 			for yy in image.get_size().y:

src/Tools/DesignTools/Pencil.gd

@@ -211,6 +211,7 @@ func _draw_brush_image(brush_image: Image, src_rect: Rect2i, dst: Vector2i) -> v
 				draw_image.blit_rect_mask(brush_image, mask, src_rect, dst)
 			else:
 				draw_image.blit_rect(brush_image, src_rect, dst)
+			draw_image.convert_rgb_to_indexed()
 	else:
 		for draw_image in images:
 			if Tools.alpha_locked:
@@ -218,3 +219,4 @@ func _draw_brush_image(brush_image: Image, src_rect: Rect2i, dst: Vector2i) -> v
 				draw_image.blend_rect_mask(brush_image, mask, src_rect, dst)
 			else:
 				draw_image.blend_rect(brush_image, src_rect, dst)
+			draw_image.convert_rgb_to_indexed()

src/Tools/UtilityTools/Move.gd

@@ -8,7 +8,7 @@ var _content_transformation_check := false
 var _snap_to_grid := false  ## Mouse Click + Ctrl
 var _undo_data := {}
 
-@onready var selection_node: Node2D = Global.canvas.selection
+@onready var selection_node := Global.canvas.selection
 
 
 func _input(event: InputEvent) -> void:
@@ -78,19 +78,15 @@ func draw_end(pos: Vector2i) -> void:
 		and _content_transformation_check == selection_node.is_moving_content
 	):
 		pos = _snap_position(pos)
-		var project := Global.current_project
-
-		if project.has_selection:
+		if Global.current_project.has_selection:
 			selection_node.move_borders_end()
 		else:
 			var pixel_diff := pos - _start_pos
 			Global.canvas.move_preview_location = Vector2i.ZERO
 			var images := _get_selected_draw_images()
 			for image in images:
-				var image_copy := Image.new()
-				image_copy.copy_from(image)
-				image.fill(Color(0, 0, 0, 0))
-				image.blit_rect(image_copy, Rect2i(Vector2i.ZERO, project.size), pixel_diff)
+				_move_image(image, pixel_diff)
+				_move_image(image.indices_image, pixel_diff)
 			_commit_undo("Draw")
 
 	_start_pos = Vector2.INF
@@ -99,6 +95,13 @@ func draw_end(pos: Vector2i) -> void:
 	Global.canvas.measurements.update_measurement(Global.MeasurementMode.NONE)
 
 
+func _move_image(image: Image, pixel_diff: Vector2i) -> void:
+	var image_copy := Image.new()
+	image_copy.copy_from(image)
+	image.fill(Color(0, 0, 0, 0))
+	image.blit_rect(image_copy, Rect2i(Vector2i.ZERO, image.get_size()), pixel_diff)
+
+
 func _snap_position(pos: Vector2) -> Vector2:
 	if Input.is_action_pressed("transform_snap_axis"):
 		var angle := pos.angle_to_point(_start_pos)
@@ -155,6 +158,6 @@ func _get_undo_data() -> Dictionary:
 	for cel in cels:
 		if not cel is PixelCel:
 			continue
-		var image: Image = cel.image
-		data[image] = image.data
+		var image := (cel as PixelCel).get_image()
+		image.add_data_to_dictionary(data)
 	return data

src/Tools/UtilityTools/Text.gd

@@ -149,12 +149,14 @@ func text_to_pixels() -> void:
 	RenderingServer.free_rid(canvas)
 	RenderingServer.free_rid(ci_rid)
 	RenderingServer.free_rid(texture)
-	viewport_texture.convert(Image.FORMAT_RGBA8)
+	viewport_texture.convert(image.get_format())
 
 	text_edit.queue_free()
 	text_edit = null
 	if not viewport_texture.is_empty():
 		image.copy_from(viewport_texture)
+		if image is ImageExtended:
+			image.convert_rgb_to_indexed()
 		commit_undo("Draw", undo_data)
 
 
@@ -179,7 +181,7 @@ func _get_undo_data() -> Dictionary:
 	var data := {}
 	var images := _get_selected_draw_images()
 	for image in images:
-		data[image] = image.data
+		image.add_data_to_dictionary(data)
 	return data
 
 

src/UI/Canvas/Selection.gd

@@ -516,6 +516,7 @@ func transform_content_confirm() -> void:
 			Rect2i(Vector2i.ZERO, project.selection_map.get_size()),
 			big_bounding_rectangle.position
 		)
+		cel_image.convert_rgb_to_indexed()
 	project.selection_map.move_bitmap_values(project)
 	commit_undo("Move Selection", undo_data)
 
@@ -605,13 +606,13 @@ func get_undo_data(undo_image: bool) -> Dictionary:
 	if undo_image:
 		var images := _get_selected_draw_images()
 		for image in images:
-			data[image] = image.data
+			image.add_data_to_dictionary(data)
 
 	return data
 
 
-func _get_selected_draw_cels() -> Array[BaseCel]:
-	var cels: Array[BaseCel] = []
+func _get_selected_draw_cels() -> Array[PixelCel]:
+	var cels: Array[PixelCel] = []
 	var project := Global.current_project
 	for cel_index in project.selected_cels:
 		var cel: BaseCel = project.frames[cel_index[0]].cels[cel_index[1]]
@@ -622,8 +623,8 @@ func _get_selected_draw_cels() -> Array[BaseCel]:
 	return cels
 
 
-func _get_selected_draw_images() -> Array[Image]:
-	var images: Array[Image] = []
+func _get_selected_draw_images() -> Array[ImageExtended]:
+	var images: Array[ImageExtended] = []
 	var project := Global.current_project
 	for cel_index in project.selected_cels:
 		var cel: BaseCel = project.frames[cel_index[0]].cels[cel_index[1]]
@@ -794,14 +795,14 @@ func delete(selected_cels := true) -> void:
 		return
 
 	var undo_data_tmp := get_undo_data(true)
-	var images: Array[Image]
+	var images: Array[ImageExtended]
 	if selected_cels:
 		images = _get_selected_draw_images()
 	else:
 		images = [project.get_current_cel().get_image()]
 
 	if project.has_selection:
-		var blank := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+		var blank := project.new_empty_image()
 		var selection_map_copy := project.selection_map.return_cropped_copy(project.size)
 		for image in images:
 			image.blit_rect_mask(
@@ -870,13 +871,16 @@ func _project_switched() -> void:
 
 func _get_preview_image() -> void:
 	var project := Global.current_project
-	var blended_image := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+	var blended_image := project.new_empty_image()
 	DrawingAlgos.blend_layers(
 		blended_image, project.frames[project.current_frame], Vector2i.ZERO, project, true
 	)
 	if original_preview_image.is_empty():
 		original_preview_image = Image.create(
-			big_bounding_rectangle.size.x, big_bounding_rectangle.size.y, false, Image.FORMAT_RGBA8
+			big_bounding_rectangle.size.x,
+			big_bounding_rectangle.size.y,
+			false,
+			project.get_image_format()
 		)
 		var selection_map_copy := project.selection_map.return_cropped_copy(project.size)
 		original_preview_image.blit_rect_mask(
@@ -892,11 +896,11 @@ func _get_preview_image() -> void:
 	var clear_image := Image.create(
 		original_preview_image.get_width(),
 		original_preview_image.get_height(),
-		false,
-		Image.FORMAT_RGBA8
+		original_preview_image.has_mipmaps(),
+		original_preview_image.get_format()
 	)
 	for cel in _get_selected_draw_cels():
-		var cel_image: Image = cel.get_image()
+		var cel_image := cel.get_image()
 		cel.transformed_content = _get_selected_image(cel_image)
 		cel_image.blit_rect_mask(
 			clear_image,
@@ -911,7 +915,10 @@ func _get_preview_image() -> void:
 func _get_selected_image(cel_image: Image) -> Image:
 	var project := Global.current_project
 	var image := Image.create(
-		big_bounding_rectangle.size.x, big_bounding_rectangle.size.y, false, Image.FORMAT_RGBA8
+		big_bounding_rectangle.size.x,
+		big_bounding_rectangle.size.y,
+		false,
+		project.get_image_format()
 	)
 	var selection_map_copy := project.selection_map.return_cropped_copy(project.size)
 	image.blit_rect_mask(cel_image, selection_map_copy, big_bounding_rectangle, Vector2i.ZERO)

src/UI/Dialogs/CreateNewImage.gd

@@ -52,7 +52,9 @@ var templates: Array[Template] = [
 @onready var height_value := %HeightValue as SpinBox
 @onready var portrait_button := %PortraitButton as Button
 @onready var landscape_button := %LandscapeButton as Button
+@onready var name_input := $VBoxContainer/FillColorContainer/NameInput as LineEdit
 @onready var fill_color_node := %FillColor as ColorPickerButton
+@onready var color_mode := $VBoxContainer/FillColorContainer/ColorMode as OptionButton
 @onready var recent_templates_list := %RecentTemplates as ItemList
 
 
@@ -123,13 +125,14 @@ func _on_CreateNewImage_confirmed() -> void:
 	if recent_sizes.size() > 10:
 		recent_sizes.resize(10)
 	Global.config_cache.set_value("templates", "recent_sizes", recent_sizes)
-	var fill_color: Color = fill_color_node.color
-
-	var proj_name: String = $VBoxContainer/ProjectName/NameInput.text
+	var fill_color := fill_color_node.color
+	var proj_name := name_input.text
 	if !proj_name.is_valid_filename():
 		proj_name = tr("untitled")
 
 	var new_project := Project.new([], proj_name, image_size)
+	if color_mode.selected == 1:
+		new_project.color_mode = Project.INDEXED_MODE
 	new_project.layers.append(PixelLayer.new(new_project))
 	new_project.fill_color = fill_color
 	new_project.frames.append(new_project.new_empty_frame())

src/UI/Dialogs/CreateNewImage.tscn

@@ -9,7 +9,8 @@
 
 [node name="CreateNewImage" type="ConfirmationDialog"]
 title = "New..."
-size = Vector2i(384, 330)
+position = Vector2i(0, 36)
+size = Vector2i(434, 330)
 script = ExtResource("1")
 
 [node name="VBoxContainer" type="VBoxContainer" parent="."]
@@ -22,19 +23,6 @@ offset_right = -8.0
 offset_bottom = -49.0
 size_flags_horizontal = 0
 
-[node name="ProjectName" type="HBoxContainer" parent="VBoxContainer"]
-layout_mode = 2
-
-[node name="NameLabel" type="Label" parent="VBoxContainer/ProjectName"]
-custom_minimum_size = Vector2(100, 0)
-layout_mode = 2
-text = "Project Name:"
-
-[node name="NameInput" type="LineEdit" parent="VBoxContainer/ProjectName"]
-layout_mode = 2
-size_flags_horizontal = 3
-placeholder_text = "Enter name... (Default \"untitled\")"
-
 [node name="ImageSize" type="Label" parent="VBoxContainer"]
 layout_mode = 2
 text = "Image Size"
@@ -42,49 +30,48 @@ text = "Image Size"
 [node name="HSeparator" type="HSeparator" parent="VBoxContainer"]
 layout_mode = 2
 
-[node name="VBoxContainer" type="HBoxContainer" parent="VBoxContainer"]
+[node name="SizeContainer" type="HBoxContainer" parent="VBoxContainer"]
 layout_mode = 2
 size_flags_vertical = 3
 
-[node name="Templates" type="VBoxContainer" parent="VBoxContainer/VBoxContainer"]
+[node name="SizeOptions" type="VBoxContainer" parent="VBoxContainer/SizeContainer"]
 layout_mode = 2
 size_flags_horizontal = 3
 
-[node name="TemplatesContainer" type="HBoxContainer" parent="VBoxContainer/VBoxContainer/Templates"]
+[node name="TemplatesContainer" type="HBoxContainer" parent="VBoxContainer/SizeContainer/SizeOptions"]
 layout_mode = 2
 
-[node name="TemplatesLabel" type="Label" parent="VBoxContainer/VBoxContainer/Templates/TemplatesContainer"]
+[node name="TemplatesLabel" type="Label" parent="VBoxContainer/SizeContainer/SizeOptions/TemplatesContainer"]
 custom_minimum_size = Vector2(100, 0)
 layout_mode = 2
 text = "Templates:"
 
-[node name="TemplatesOptions" type="OptionButton" parent="VBoxContainer/VBoxContainer/Templates/TemplatesContainer"]
+[node name="TemplatesOptions" type="OptionButton" parent="VBoxContainer/SizeContainer/SizeOptions/TemplatesContainer"]
 unique_name_in_owner = true
 layout_mode = 2
 size_flags_horizontal = 3
 mouse_default_cursor_shape = 2
 toggle_mode = false
-item_count = 1
 selected = 0
+item_count = 1
 popup/item_0/text = "Default"
-popup/item_0/id = 0
 
-[node name="SizeContainer" type="HBoxContainer" parent="VBoxContainer/VBoxContainer/Templates"]
+[node name="WidthHeightContainer" type="HBoxContainer" parent="VBoxContainer/SizeContainer/SizeOptions"]
 layout_mode = 2
 
-[node name="VBoxContainer" type="VBoxContainer" parent="VBoxContainer/VBoxContainer/Templates/SizeContainer"]
+[node name="VBoxContainer" type="VBoxContainer" parent="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer"]
 layout_mode = 2
 size_flags_horizontal = 3
 
-[node name="WidthContainer" type="HBoxContainer" parent="VBoxContainer/VBoxContainer/Templates/SizeContainer/VBoxContainer"]
+[node name="WidthContainer" type="HBoxContainer" parent="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/VBoxContainer"]
 layout_mode = 2
 
-[node name="WidthLabel" type="Label" parent="VBoxContainer/VBoxContainer/Templates/SizeContainer/VBoxContainer/WidthContainer"]
+[node name="WidthLabel" type="Label" parent="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/VBoxContainer/WidthContainer"]
 custom_minimum_size = Vector2(100, 0)
 layout_mode = 2
 text = "Width:"
 
-[node name="WidthValue" type="SpinBox" parent="VBoxContainer/VBoxContainer/Templates/SizeContainer/VBoxContainer/WidthContainer"]
+[node name="WidthValue" type="SpinBox" parent="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/VBoxContainer/WidthContainer"]
 unique_name_in_owner = true
 layout_mode = 2
 size_flags_horizontal = 3
@@ -94,15 +81,15 @@ max_value = 16384.0
 value = 64.0
 suffix = "px"
 
-[node name="HeightContainer" type="HBoxContainer" parent="VBoxContainer/VBoxContainer/Templates/SizeContainer/VBoxContainer"]
+[node name="HeightContainer" type="HBoxContainer" parent="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/VBoxContainer"]
 layout_mode = 2
 
-[node name="HeightLabel" type="Label" parent="VBoxContainer/VBoxContainer/Templates/SizeContainer/VBoxContainer/HeightContainer"]
+[node name="HeightLabel" type="Label" parent="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/VBoxContainer/HeightContainer"]
 custom_minimum_size = Vector2(100, 0)
 layout_mode = 2
 text = "Height:"
 
-[node name="HeightValue" type="SpinBox" parent="VBoxContainer/VBoxContainer/Templates/SizeContainer/VBoxContainer/HeightContainer"]
+[node name="HeightValue" type="SpinBox" parent="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/VBoxContainer/HeightContainer"]
 unique_name_in_owner = true
 layout_mode = 2
 size_flags_horizontal = 3
@@ -112,11 +99,11 @@ max_value = 16384.0
 value = 64.0
 suffix = "px"
 
-[node name="TextureRect" type="TextureRect" parent="VBoxContainer/VBoxContainer/Templates/SizeContainer" groups=["UIButtons"]]
+[node name="TextureRect" type="TextureRect" parent="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer" groups=["UIButtons"]]
 layout_mode = 2
 texture = ExtResource("6")
 
-[node name="AspectRatioButton" type="TextureButton" parent="VBoxContainer/VBoxContainer/Templates/SizeContainer/TextureRect" groups=["UIButtons"]]
+[node name="AspectRatioButton" type="TextureButton" parent="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/TextureRect" groups=["UIButtons"]]
 unique_name_in_owner = true
 layout_mode = 0
 anchor_left = 0.5
@@ -133,31 +120,10 @@ toggle_mode = true
 texture_normal = ExtResource("4")
 texture_pressed = ExtResource("5")
 
-[node name="VSeparator" type="VSeparator" parent="VBoxContainer/VBoxContainer"]
+[node name="SizeButtonsContainer" type="HBoxContainer" parent="VBoxContainer/SizeContainer/SizeOptions"]
 layout_mode = 2
 
-[node name="VBoxContainer" type="VBoxContainer" parent="VBoxContainer/VBoxContainer"]
-clip_contents = true
-custom_minimum_size = Vector2(150, 0)
-layout_mode = 2
-focus_mode = 2
-mouse_filter = 0
-
-[node name="Label" type="Label" parent="VBoxContainer/VBoxContainer/VBoxContainer"]
-layout_mode = 2
-text = "Recent:"
-
-[node name="RecentTemplates" type="ItemList" parent="VBoxContainer/VBoxContainer/VBoxContainer"]
-unique_name_in_owner = true
-layout_mode = 2
-size_flags_horizontal = 3
-size_flags_vertical = 3
-allow_reselect = true
-
-[node name="SizeButtonsContainer" type="HBoxContainer" parent="VBoxContainer"]
-layout_mode = 2
-
-[node name="PortraitButton" type="Button" parent="VBoxContainer/SizeButtonsContainer" groups=["UIButtons"]]
+[node name="PortraitButton" type="Button" parent="VBoxContainer/SizeContainer/SizeOptions/SizeButtonsContainer" groups=["UIButtons"]]
 unique_name_in_owner = true
 custom_minimum_size = Vector2(24, 24)
 layout_mode = 2
@@ -166,7 +132,7 @@ focus_mode = 0
 mouse_default_cursor_shape = 2
 toggle_mode = true
 
-[node name="TextureRect" type="TextureRect" parent="VBoxContainer/SizeButtonsContainer/PortraitButton"]
+[node name="TextureRect" type="TextureRect" parent="VBoxContainer/SizeContainer/SizeOptions/SizeButtonsContainer/PortraitButton"]
 layout_mode = 0
 anchor_left = 0.5
 anchor_top = 0.5
@@ -178,7 +144,7 @@ offset_right = 8.0
 offset_bottom = 8.0
 texture = ExtResource("2")
 
-[node name="LandscapeButton" type="Button" parent="VBoxContainer/SizeButtonsContainer" groups=["UIButtons"]]
+[node name="LandscapeButton" type="Button" parent="VBoxContainer/SizeContainer/SizeOptions/SizeButtonsContainer" groups=["UIButtons"]]
 unique_name_in_owner = true
 custom_minimum_size = Vector2(24, 24)
 layout_mode = 2
@@ -187,7 +153,7 @@ focus_mode = 0
 mouse_default_cursor_shape = 2
 toggle_mode = true
 
-[node name="TextureRect" type="TextureRect" parent="VBoxContainer/SizeButtonsContainer/LandscapeButton"]
+[node name="TextureRect" type="TextureRect" parent="VBoxContainer/SizeContainer/SizeOptions/SizeButtonsContainer/LandscapeButton"]
 layout_mode = 0
 anchor_left = 0.5
 anchor_top = 0.5
@@ -199,12 +165,49 @@ offset_right = 8.0
 offset_bottom = 8.0
 texture = ExtResource("3")
 
-[node name="FillColorContainer" type="HBoxContainer" parent="VBoxContainer"]
+[node name="VSeparator" type="VSeparator" parent="VBoxContainer/SizeContainer"]
 layout_mode = 2
 
+[node name="VBoxContainer" type="VBoxContainer" parent="VBoxContainer/SizeContainer"]
+clip_contents = true
+custom_minimum_size = Vector2(150, 0)
+layout_mode = 2
+focus_mode = 2
+mouse_filter = 0
+
+[node name="Label" type="Label" parent="VBoxContainer/SizeContainer/VBoxContainer"]
+layout_mode = 2
+text = "Recent:"
+
+[node name="RecentTemplates" type="ItemList" parent="VBoxContainer/SizeContainer/VBoxContainer"]
+unique_name_in_owner = true
+layout_mode = 2
+size_flags_horizontal = 3
+size_flags_vertical = 3
+allow_reselect = true
+
+[node name="HSeparator2" type="HSeparator" parent="VBoxContainer"]
+layout_mode = 2
+
+[node name="FillColorContainer" type="GridContainer" parent="VBoxContainer"]
+layout_mode = 2
+columns = 2
+
+[node name="NameLabel" type="Label" parent="VBoxContainer/FillColorContainer"]
+custom_minimum_size = Vector2(100, 0)
+layout_mode = 2
+size_flags_horizontal = 3
+text = "Project Name:"
+
+[node name="NameInput" type="LineEdit" parent="VBoxContainer/FillColorContainer"]
+layout_mode = 2
+size_flags_horizontal = 3
+placeholder_text = "Enter name... (Default \"untitled\")"
+
 [node name="FillColorLabel" type="Label" parent="VBoxContainer/FillColorContainer"]
 custom_minimum_size = Vector2(100, 0)
 layout_mode = 2
+size_flags_horizontal = 3
 text = "Fill with color:"
 
 [node name="FillColor" type="ColorPickerButton" parent="VBoxContainer/FillColorContainer"]
@@ -215,13 +218,28 @@ size_flags_horizontal = 3
 mouse_default_cursor_shape = 2
 color = Color(0, 0, 0, 0)
 
+[node name="ColorModeLabel" type="Label" parent="VBoxContainer/FillColorContainer"]
+custom_minimum_size = Vector2(100, 0)
+layout_mode = 2
+size_flags_horizontal = 3
+text = "Color mode:"
+
+[node name="ColorMode" type="OptionButton" parent="VBoxContainer/FillColorContainer"]
+layout_mode = 2
+mouse_default_cursor_shape = 2
+selected = 0
+item_count = 2
+popup/item_0/text = "RGBA"
+popup/item_1/text = "Indexed"
+popup/item_1/id = 1
+
 [connection signal="about_to_popup" from="." to="." method="_on_CreateNewImage_about_to_show"]
 [connection signal="confirmed" from="." to="." method="_on_CreateNewImage_confirmed"]
 [connection signal="visibility_changed" from="." to="." method="_on_visibility_changed"]
-[connection signal="item_selected" from="VBoxContainer/VBoxContainer/Templates/TemplatesContainer/TemplatesOptions" to="." method="_on_TemplatesOptions_item_selected"]
-[connection signal="value_changed" from="VBoxContainer/VBoxContainer/Templates/SizeContainer/VBoxContainer/WidthContainer/WidthValue" to="." method="_on_SizeValue_value_changed"]
-[connection signal="value_changed" from="VBoxContainer/VBoxContainer/Templates/SizeContainer/VBoxContainer/HeightContainer/HeightValue" to="." method="_on_SizeValue_value_changed"]
-[connection signal="toggled" from="VBoxContainer/VBoxContainer/Templates/SizeContainer/TextureRect/AspectRatioButton" to="." method="_on_AspectRatioButton_toggled"]
-[connection signal="item_selected" from="VBoxContainer/VBoxContainer/VBoxContainer/RecentTemplates" to="." method="_on_RecentTemplates_item_selected"]
-[connection signal="toggled" from="VBoxContainer/SizeButtonsContainer/PortraitButton" to="." method="_on_PortraitButton_toggled"]
-[connection signal="toggled" from="VBoxContainer/SizeButtonsContainer/LandscapeButton" to="." method="_on_LandscapeButton_toggled"]
+[connection signal="item_selected" from="VBoxContainer/SizeContainer/SizeOptions/TemplatesContainer/TemplatesOptions" to="." method="_on_TemplatesOptions_item_selected"]
+[connection signal="value_changed" from="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/VBoxContainer/WidthContainer/WidthValue" to="." method="_on_SizeValue_value_changed"]
+[connection signal="value_changed" from="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/VBoxContainer/HeightContainer/HeightValue" to="." method="_on_SizeValue_value_changed"]
+[connection signal="toggled" from="VBoxContainer/SizeContainer/SizeOptions/WidthHeightContainer/TextureRect/AspectRatioButton" to="." method="_on_AspectRatioButton_toggled"]
+[connection signal="toggled" from="VBoxContainer/SizeContainer/SizeOptions/SizeButtonsContainer/PortraitButton" to="." method="_on_PortraitButton_toggled"]
+[connection signal="toggled" from="VBoxContainer/SizeContainer/SizeOptions/SizeButtonsContainer/LandscapeButton" to="." method="_on_LandscapeButton_toggled"]
+[connection signal="item_selected" from="VBoxContainer/SizeContainer/VBoxContainer/RecentTemplates" to="." method="_on_RecentTemplates_item_selected"]

src/UI/Dialogs/ImageEffects/RotateImage.gd

@@ -89,7 +89,7 @@ func commit_action(cel: Image, project := Global.current_project) -> void:
 		selection_tex = ImageTexture.create_from_image(selection)
 
 		if !_type_is_shader():
-			var blank := Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+			var blank := project.new_empty_image()
 			cel.blit_rect_mask(
 				blank, selection, Rect2i(Vector2i.ZERO, cel.get_size()), Vector2i.ZERO
 			)
@@ -136,6 +136,8 @@ func commit_action(cel: Image, project := Global.current_project) -> void:
 			cel.blend_rect(image, Rect2i(Vector2i.ZERO, image.get_size()), Vector2i.ZERO)
 		else:
 			cel.blit_rect(image, Rect2i(Vector2i.ZERO, image.get_size()), Vector2i.ZERO)
+		if cel is ImageExtended:
+			cel.convert_rgb_to_indexed()
 
 
 func _type_is_shader() -> bool:

src/UI/Dialogs/ImageEffects/ScaleImage.gd

@@ -34,7 +34,7 @@ func _on_ScaleImage_confirmed() -> void:
 	var width: int = width_value.value
 	var height: int = height_value.value
 	var interpolation: int = interpolation_type.selected
-	DrawingAlgos.scale_image(width, height, interpolation)
+	DrawingAlgos.scale_project(width, height, interpolation)
 
 
 func _on_visibility_changed() -> void:

src/UI/Dialogs/ImportTagDialog.gd

@@ -22,7 +22,7 @@ func refresh_list() -> void:
 	animation_tags_list.clear()
 	get_ok_button().disabled = true
 	for tag: AnimationTag in from_project.animation_tags:
-		var img = Image.create(from_project.size.x, from_project.size.y, true, Image.FORMAT_RGBA8)
+		var img := from_project.new_empty_image()
 		DrawingAlgos.blend_layers(
 			img, from_project.frames[tag.from - 1], Vector2i.ZERO, from_project
 		)
@@ -186,9 +186,7 @@ func add_animation(indices: Array, destination: int, from_tag: AnimationTag = nu
 					# add more types here if they have a copy_content() method
 					if src_cel is PixelCel:
 						var src_img = src_cel.copy_content()
-						var copy := Image.create(
-							project.size.x, project.size.y, false, Image.FORMAT_RGBA8
-						)
+						var copy := project.new_empty_image()
 						copy.blit_rect(
 							src_img, Rect2(Vector2.ZERO, src_img.get_size()), Vector2.ZERO
 						)

src/UI/Dialogs/ProjectProperties.gd

@@ -1,6 +1,7 @@
 extends AcceptDialog
 
 @onready var size_value_label := $GridContainer/SizeValueLabel as Label
+@onready var color_mode_value_label := $GridContainer/ColorModeValueLabel as Label
 @onready var frames_value_label := $GridContainer/FramesValueLabel as Label
 @onready var layers_value_label := $GridContainer/LayersValueLabel as Label
 @onready var name_line_edit := $GridContainer/NameLineEdit as LineEdit
@@ -10,6 +11,12 @@ extends AcceptDialog
 func _on_visibility_changed() -> void:
 	Global.dialog_open(visible)
 	size_value_label.text = str(Global.current_project.size)
+	if Global.current_project.get_image_format() == Image.FORMAT_RGBA8:
+		color_mode_value_label.text = "RGBA8"
+	else:
+		color_mode_value_label.text = str(Global.current_project.get_image_format())
+	if Global.current_project.is_indexed():
+		color_mode_value_label.text += " (%s)" % tr("Indexed")
 	frames_value_label.text = str(Global.current_project.frames.size())
 	layers_value_label.text = str(Global.current_project.layers.size())
 	name_line_edit.text = Global.current_project.name

src/UI/Dialogs/ProjectProperties.tscn

@@ -24,6 +24,16 @@ layout_mode = 2
 size_flags_horizontal = 3
 text = "64x64"
 
+[node name="ColorModeLabel" type="Label" parent="GridContainer"]
+layout_mode = 2
+size_flags_horizontal = 3
+text = "Color mode:"
+
+[node name="ColorModeValueLabel" type="Label" parent="GridContainer"]
+layout_mode = 2
+size_flags_horizontal = 3
+text = "RGBA8"
+
 [node name="FramesLabel" type="Label" parent="GridContainer"]
 layout_mode = 2
 size_flags_horizontal = 3
@@ -32,7 +42,7 @@ text = "Frames:"
 [node name="FramesValueLabel" type="Label" parent="GridContainer"]
 layout_mode = 2
 size_flags_horizontal = 3
-text = "64x64"
+text = "1"
 
 [node name="LayersLabel" type="Label" parent="GridContainer"]
 layout_mode = 2
@@ -42,7 +52,7 @@ text = "Layers:"
 [node name="LayersValueLabel" type="Label" parent="GridContainer"]
 layout_mode = 2
 size_flags_horizontal = 3
-text = "64x64"
+text = "1"
 
 [node name="NameLabel" type="Label" parent="GridContainer"]
 layout_mode = 2

src/UI/Recorder/Recorder.gd

@@ -70,7 +70,7 @@ class Recorder:
 			image = recorder_panel.get_window().get_texture().get_image()
 		else:
 			var frame := project.frames[project.current_frame]
-			image = Image.create(project.size.x, project.size.y, false, Image.FORMAT_RGBA8)
+			image = project.new_empty_image()
 			DrawingAlgos.blend_layers(image, frame, Vector2i.ZERO, project)
 
 			if recorder_panel.resize_percent != 100:

src/UI/Timeline/AnimationTimeline.gd

@@ -1045,9 +1045,10 @@ func _on_MergeDownLayer_pressed() -> void:
 		top_cels.append(top_cel)  # Store for undo purposes
 
 		var top_image := top_layer.display_effects(top_cel)
-		var bottom_cel := frame.cels[bottom_layer.index]
+		var bottom_cel := frame.cels[bottom_layer.index] as PixelCel
+		var bottom_image := bottom_cel.get_image()
 		var textures: Array[Image] = []
-		textures.append(bottom_cel.get_image())
+		textures.append(bottom_image)
 		textures.append(top_image)
 		var metadata_image := Image.create(2, 4, false, Image.FORMAT_R8)
 		DrawingAlgos.set_layer_metadata_image(bottom_layer, bottom_cel, metadata_image, 0)
@@ -1058,12 +1059,17 @@ func _on_MergeDownLayer_pressed() -> void:
 		var params := {
 			"layers": texture_array, "metadata": ImageTexture.create_from_image(metadata_image)
 		}
-		var bottom_image := Image.create(
-			top_image.get_width(), top_image.get_height(), false, top_image.get_format()
+		var new_bottom_image := ImageExtended.create_custom(
+			top_image.get_width(),
+			top_image.get_height(),
+			top_image.has_mipmaps(),
+			top_image.get_format(),
+			project.is_indexed()
 		)
+		# Merge the image itself.
 		var gen := ShaderImageEffect.new()
-		gen.generate_image(bottom_image, DrawingAlgos.blend_layers_shader, params, project.size)
-
+		gen.generate_image(new_bottom_image, DrawingAlgos.blend_layers_shader, params, project.size)
+		new_bottom_image.convert_rgb_to_indexed()
 		if (
 			bottom_cel.link_set != null
 			and bottom_cel.link_set.size() > 1
@@ -1074,14 +1080,14 @@ func _on_MergeDownLayer_pressed() -> void:
 			project.undo_redo.add_undo_method(
 				bottom_layer.link_cel.bind(bottom_cel, bottom_cel.link_set)
 			)
-			project.undo_redo.add_do_property(bottom_cel, "image", bottom_image)
+			project.undo_redo.add_do_property(bottom_cel, "image", new_bottom_image)
 			project.undo_redo.add_undo_property(bottom_cel, "image", bottom_cel.image)
 		else:
-			Global.undo_redo_compress_images(
-				{bottom_cel.image: bottom_image.data},
-				{bottom_cel.image: bottom_cel.image.data},
-				project
-			)
+			var redo_data := {}
+			var undo_data := {}
+			new_bottom_image.add_data_to_dictionary(redo_data, bottom_image)
+			bottom_image.add_data_to_dictionary(undo_data)
+			Global.undo_redo_compress_images(redo_data, undo_data, project)
 
 	project.undo_redo.add_do_method(project.remove_layers.bind([top_layer.index]))
 	project.undo_redo.add_undo_method(

src/UI/Timeline/LayerEffects/LayerEffectsSettings.gd

@@ -154,13 +154,19 @@ func _apply_effect(layer: BaseLayer, effect: LayerEffect) -> void:
 	var undo_data := {}
 	for frame in Global.current_project.frames:
 		var cel := frame.cels[layer.index]
-		var new_image := Image.new()
-		new_image.copy_from(cel.get_image())
+		var new_image := ImageExtended.new()
+		var cel_image := cel.get_image()
+		if cel_image is ImageExtended:
+			new_image.is_indexed = cel_image.is_indexed
+		new_image.copy_from_custom(cel_image)
 		var image_size := new_image.get_size()
 		var shader_image_effect := ShaderImageEffect.new()
 		shader_image_effect.generate_image(new_image, effect.shader, effect.params, image_size)
-		redo_data[cel.image] = new_image.data
-		undo_data[cel.image] = cel.image.data
+		if cel_image is ImageExtended:
+			redo_data[cel_image.indices_image] = new_image.indices_image.data
+			undo_data[cel_image.indices_image] = cel_image.indices_image.data
+		redo_data[cel_image] = new_image.data
+		undo_data[cel_image] = cel_image.data
 	Global.current_project.undos += 1
 	Global.current_project.undo_redo.create_action("Apply layer effect")
 	Global.undo_redo_compress_images(redo_data, undo_data)

src/UI/TopMenuContainer/TopMenuContainer.gd

@@ -1,5 +1,7 @@
 extends Panel
 
+enum ColorModes { RGBA, INDEXED }
+
 const DOCS_URL := "https://www.oramainteractive.com/Pixelorama-Docs/"
 const ISSUES_URL := "https://github.com/Orama-Interactive/Pixelorama/issues"
 const SUPPORT_URL := "https://www.patreon.com/OramaInteractive"
@@ -56,6 +58,7 @@ var about_dialog := Dialog.new("res://src/UI/Dialogs/AboutDialog.tscn")
 @onready var greyscale_vision: ColorRect = main_ui.find_child("GreyscaleVision")
 @onready var tile_mode_submenu := PopupMenu.new()
 @onready var selection_modify_submenu := PopupMenu.new()
+@onready var color_mode_submenu := PopupMenu.new()
 @onready var snap_to_submenu := PopupMenu.new()
 @onready var panels_submenu := PopupMenu.new()
 @onready var layouts_submenu := PopupMenu.new()
@@ -124,6 +127,7 @@ func _project_switched() -> void:
 	_update_file_menu_buttons(project)
 	for j in Tiles.MODE.values():
 		tile_mode_submenu.set_item_checked(j, j == project.tiles.mode)
+	_check_color_mode_submenu_item(project)
 
 	_update_current_frame_mark()
 
@@ -396,19 +400,34 @@ func _setup_image_menu() -> void:
 	# Order as in Global.ImageMenu enum
 	var image_menu_items := {
 		"Project Properties": "project_properties",
+		"Color Mode": "",
 		"Resize Canvas": "resize_canvas",
 		"Scale Image": "scale_image",
 		"Crop to Selection": "crop_to_selection",
 		"Crop to Content": "crop_to_content",
 	}
-	var i := 0
-	for item in image_menu_items:
+	for i in image_menu_items.size():
+		var item: String = image_menu_items.keys()[i]
+		if item == "Color Mode":
+			_setup_color_mode_submenu(item)
+		else:
 			_set_menu_shortcut(image_menu_items[item], image_menu, i, item)
-		i += 1
 	image_menu.set_item_disabled(Global.ImageMenu.CROP_TO_SELECTION, true)
 	image_menu.id_pressed.connect(image_menu_id_pressed)
 
 
+func _setup_color_mode_submenu(item: String) -> void:
+	color_mode_submenu.set_name("color_mode_submenu")
+	color_mode_submenu.add_radio_check_item("RGBA", ColorModes.RGBA)
+	color_mode_submenu.set_item_checked(ColorModes.RGBA, true)
+	color_mode_submenu.add_radio_check_item("Indexed", ColorModes.INDEXED)
+	color_mode_submenu.hide_on_checkable_item_selection = false
+
+	color_mode_submenu.id_pressed.connect(_color_mode_submenu_id_pressed)
+	image_menu.add_child(color_mode_submenu)
+	image_menu.add_submenu_item(item, color_mode_submenu.get_name())
+
+
 func _setup_effects_menu() -> void:
 	# Order as in Global.EffectMenu enum
 	var menu_items := {
@@ -687,6 +706,38 @@ func _selection_modify_submenu_id_pressed(id: int) -> void:
 	modify_selection.node.type = id
 
 
+func _color_mode_submenu_id_pressed(id: ColorModes) -> void:
+	var project := Global.current_project
+	var old_color_mode := project.color_mode
+	var redo_data := {}
+	var undo_data := {}
+	for cel in project.get_all_pixel_cels():
+		cel.get_image().add_data_to_dictionary(undo_data)
+	# Change the color mode directly before undo/redo in order to affect the images,
+	# so we can store them as redo data.
+	if id == ColorModes.RGBA:
+		project.color_mode = Image.FORMAT_RGBA8
+	else:
+		project.color_mode = Project.INDEXED_MODE
+	for cel in project.get_all_pixel_cels():
+		cel.get_image().add_data_to_dictionary(redo_data)
+	project.undo_redo.create_action("Change color mode")
+	project.undos += 1
+	project.undo_redo.add_do_property(project, "color_mode", project.color_mode)
+	project.undo_redo.add_undo_property(project, "color_mode", old_color_mode)
+	Global.undo_redo_compress_images(redo_data, undo_data, project)
+	project.undo_redo.add_do_method(_check_color_mode_submenu_item.bind(project))
+	project.undo_redo.add_undo_method(_check_color_mode_submenu_item.bind(project))
+	project.undo_redo.add_do_method(Global.undo_or_redo.bind(false))
+	project.undo_redo.add_undo_method(Global.undo_or_redo.bind(true))
+	project.undo_redo.commit_action()
+
+
+func _check_color_mode_submenu_item(project: Project) -> void:
+	color_mode_submenu.set_item_checked(ColorModes.RGBA, project.color_mode == Image.FORMAT_RGBA8)
+	color_mode_submenu.set_item_checked(ColorModes.INDEXED, project.is_indexed())
+
+
 func _snap_to_submenu_id_pressed(id: int) -> void:
 	if id == 0:
 		Global.snap_to_rectangular_grid_boundary = !Global.snap_to_rectangular_grid_boundary