EngineAnalysisBoard

Engine analysis board

The pgn4web chess engine analysis board is an optional module allowing for a popup analysis board to be invoked by the user with the E8 shortcut square (assuming White on bottom, D1 otherwise). The analysis board captures the current position and activates the chess engine, presenting both the calculated principal variation and the resulting position evaluation (hover the mouse on the evaluation symbol to read the numeric evaluation in pawn units). The engine stops analyzing after a set amount of time.

end user notes

Activate the engine analysis board clicking the E8 (assuming White on bottom, D1 otherwise) shortcut square on the main chessboard.

User commands for the engine analysis board:

• explore variations by clicking the from and to squares for the intended move
• click the arrow buttons to move back/forth through the variation being analyzed
• click the plus button at the left of the arrow buttons to force the engine analysis board to auto update following the position of the main chessboard; this is useful for instance when following a live broadcast; limitations: some pages might not offer this functionality and some browsers do not support this functionality
• click on the side to move indicator to switch the side to move; this is useful to check for threats in the given position
• click on the principal variation to execute its first move on the engine analysis board
• click on the evaluation mark to activate/deactivate the engine

In the chessboard below, browse to an interesting position then try clicking the E8 shortcut square (assuming White on bottom, D1 otherwise); the engine analysis popup board will appear, try alternative moves and variations and check the engine assessment:

Click here for an example.

The analysis module uses the GarboChess chess engine. The performance of the javascript based engine is relatively limited compared to professional engines optimized for each processing environment; use the pgn4web analysis board for quick high-level assessments, for detailed analysis please refer to a chess engine optimized for the chosen computing platform.

Limitation: the chess engine of the analysis module requires a recent browser with support for the web worker functionality; if the chess engine is not available the user can still try moves and explore variations on the analysis board.

The chess engine analysis module is an optional component and it is not enabled by default on pgn4web chessboards.

screenshot

developer notes

In order to enable the engine analysis board simply include the engine.js javascript file right after the main pgn4web.js

<script src="pgn4web.js" type="text/javascript"></script>
<script src="engine.js" type="text/javascript"></script>

A set of javascript variables configure the engine analysis board behavior; those are defined at the top of engine.js and can be redefined the HTML code after the inclusion of engine.js

By default the engine analysis board opens as a popup window; optionally the engine analysis board can be directed to an inline frame of the main page, using the javascript variable of engine.js defining the target window for the engine analysis board.