Add a "Select pixels" option in the right click popup menu button of cel buttons

Translations/Translations.pot

@@ -2377,10 +2377,16 @@ msgstr ""
 msgid "Add Frame Tag"
 msgstr ""
 
-msgid "Link Cels to"
+#. An option found in the right click menu of a cel. If selected, all non-transparent pixels of that cel get selected.
+msgid "Select pixels"
 msgstr ""
 
-msgid "Unlink Cels"
+#. An option found in the right click menu of a cel. If selected, all selected cels get linked together.
+msgid "Link cels to"
+msgstr ""
+
+#. An option found in the right click menu of a cel. If selected, all selected cels get unlinked.
+msgid "Unlink cels"
 msgstr ""
 
 #. An option found in the right click menu of an audio cel. If selected, the audio of the audio layer will start playing from this frame.

src/UI/Canvas/Selection.gd

@@ -1042,6 +1042,25 @@ func select_cel_rect() -> void:
 	commit_undo("Select", undo_data_tmp)
 
 
+func select_cel_pixels(layer: BaseLayer, frame: Frame) -> void:
+	transform_content_confirm()
+	var project := Global.current_project
+	var undo_data_tmp := get_undo_data(false)
+	project.selection_map.crop(project.size.x, project.size.y)
+	project.selection_map.clear()
+	var current_cel := frame.cels[layer.index]
+	var cel_image: Image
+	if current_cel is GroupCel:
+		cel_image = (layer as GroupLayer).blend_children(frame)
+	else:
+		cel_image = current_cel.get_image()
+	project.selection_map.copy_from(cel_image)
+	project.selection_map_changed()
+	big_bounding_rectangle = project.selection_map.get_used_rect()
+	project.selection_offset = Vector2.ZERO
+	commit_undo("Select", undo_data_tmp)
+
+
 func _project_switched() -> void:
 	marching_ants_outline.offset = Global.current_project.selection_offset
 	big_bounding_rectangle = Global.current_project.selection_map.get_used_rect()

src/UI/Timeline/CelButton.gd

@@ -1,6 +1,6 @@
 extends Button
 
-enum MenuOptions { PROPERTIES, DELETE, LINK, UNLINK }
+enum MenuOptions { PROPERTIES, SELECT_PIXELS, DELETE, LINK, UNLINK }
 
 var frame := 0
 var layer := 0
@@ -25,13 +25,7 @@ func _ready() -> void:
 	for selected in Global.current_project.selected_cels:
 		if selected[1] == layer and selected[0] == frame:
 			button_pressed = true
-	if cel is PixelCel:
+	if cel is AudioCel:
-		popup_menu.add_item("Delete")
-		popup_menu.add_item("Link Cels to")
-		popup_menu.add_item("Unlink Cels")
-	elif cel is GroupCel:
-		transparent_checker.visible = false
-	elif cel is AudioCel:
 		popup_menu.add_item("Play audio here")
 		_is_playing_audio()
 		Global.cel_switched.connect(_is_playing_audio)
@@ -39,6 +33,14 @@ func _ready() -> void:
 		Global.current_project.fps_changed.connect(_is_playing_audio)
 		Global.current_project.layers[layer].audio_changed.connect(_is_playing_audio)
 		Global.current_project.layers[layer].playback_frame_changed.connect(_is_playing_audio)
+	else:
+		popup_menu.add_item("Select pixels")
+	if cel is PixelCel:
+		popup_menu.add_item("Delete")
+		popup_menu.add_item("Link cels to")
+		popup_menu.add_item("Unlink cels")
+	elif cel is GroupCel:
+		transparent_checker.visible = false
 
 
 func _notification(what: int) -> void:
@@ -132,19 +134,21 @@ func _on_CelButton_pressed() -> void:
 
 
 func _on_PopupMenu_id_pressed(id: int) -> void:
+	var project := Global.current_project
 	match id:
 		MenuOptions.PROPERTIES:
 			properties.cel_indices = _get_cel_indices()
 			properties.popup_centered()
-		MenuOptions.DELETE:
+		MenuOptions.SELECT_PIXELS:
-			var layer_class := Global.current_project.layers[layer]
+			var layer_class := project.layers[layer]
 			if layer_class is AudioLayer:
 				layer_class.playback_frame = frame
 			else:
-				_delete_cel_content()
+				Global.canvas.selection.select_cel_pixels(layer_class, project.frames[frame])
+		MenuOptions.DELETE:
+			_delete_cel_content()
 
 		MenuOptions.LINK, MenuOptions.UNLINK:
-			var project := Global.current_project
 			if id == MenuOptions.UNLINK:
 				project.undo_redo.create_action("Unlink Cel")
 				var selected_cels := _get_cel_indices(true)