Lantern Chess an interface for Mac, Linux and Windows supports analysis while the user is examining or observing a chess game on Chessclub.com, controllable from the Options menu or toolbar's toggle engine button. If the user has multiple game tabs, the chess engine will analyze the game in the currently active tab (the board window need not be active if just one board is open). When a game that is analyzing ends, Lantern stops the program; the user can also use the Stop Engine menu item at any time.
Lantern supports two kinds of analysis, with the Load UCI Engine and Load Winboard Engine menu options. An example of a Winboard program is Crafty. The UCI protocol include Rybka, Stockfish, Komodo and Houdini. Lantern now comes bundled with Stockfish 15 for Windows and Mac users and when examining or observing can activate it by going to Options menu or toggle engine on toolbar (this will start the default stockfish if no other engine loaded).
Analysis appears in the board console and is scored from white's perspective, not the side to move. Clicking on the tab of the game being analyzed toggles the view between the standard board console output (i.e., kibitzes and whispers, etc.) and the analysis output. The chess program will follow along, refreshing its analysis, as moves are played and the position changes.
If the analysis has stopped, and the user wants to start it on a different game, the Restart Engine menu item will start analysis using the same program the user had previously loaded. Toggle engine on toolbar now also does same thing.
The Multiple Lines(UCI) sub menu allows the user to choose between having a UCI engine analyze one line at once, two lines or three. This is a saved setting. If the engine is running, it must be stopped and restarted for a change in lines to take effect. The program used must also support multiple lines. All the better grade ones do.
It is possible to go beyond three lines selectable in the UI if the user reads the bottom section of this page on making a script file to send UCI commands to program. The multi line command needed is also there.
In the Analysis Display submenu, the user can customize properties like the text color and font (including its size) of analysis and the background color, to be different from the standard console settings, as can be seen in the above image. A white background and Arial font are currently default.
Lantern has been tested to make sure any analysis stops when a played game starts, in compliance with the ICC server rules for non-(C)omputer accounts.
Stockfish 15 comes bundled with Lantern for Windows and Mac users and it can be activated on Options or toolbar. On first selecting this the user is prompted to let the app extract the engine to the Lantern folder. Afterwards going to this function automaticaly starts the engine.
On other engines submenu there is an option to analyze with Cuckoo Chess, a Java engine which comes bundled with the jar that is downloaded. These Java Engines only work in examine mode were UCI engines loaded like Stockfish will work in observed mode as well. Cuckoo Chess is rated 2588 computer chess elo. This rating is similar to FIDE for slow games. The user can download their own engines or use both. Additionally on the Other Engines sub menu, there is Mediocre Chess V0.5 is there, rated 2319 on the Computer chess rating list. Note - for those using Lantern on Mac or Windows with an Installer, these Java engines require Jave be installed on computer to run. Both engines are under GPL licence and the user can extract the contents of the Lantern Jar if they wish to get the engines folder which has CuckooChess and Mediocre Chess. Their readme's I created with information on how to get their source are in the Engines folder.
Users can create a file named lantern_uci_script.txt in the Lantern folder and place valid UCI parameters to the engine in it. On Windows and Mac this folder is Documents/LanternChess. On Windows .txt files can be created in Notepad. On Mac use TextEdit and change format in format menu to text and give it the .txt extension on saving.
Multiple UCI parameters may be used in one script, with each one on a new line. These parameters will be sent when the chess engine is loaded. For example, setoption name MultiPV value 2 turns on multiple variation support, if the engine supports it, and then shows the top two current moves with a line for each. (Note as of Lantern 5.66 the number of lines of analysis is settable in the Multiple Lines(UCI) sub menu. If the user chooses One Line(Default) then a script parameter that is different can be used otherwise it is ignored.) Another useful parameter is setoption name Threads value 1, as some programs, like Houdini, use all available cores by default. Conversely, others, use one core by default, so the user can also set it to use more cores.