This page collects helpful information about using GammonSnap and explains some of the app’s current features and limitations. It is meant to help you get better results, understand how the app works, and solve common issues.
If you cannot find what you are looking for, have a suggestion, or want to report a bug, feel free to contact me:
info@gammonsnap.de
GammonSnap works best when the whole backgammon board is visible in the image. Slightly cut-off corners are usually fine, but the app needs to see almost the entire board. Photos that only show one half of the board cannot be analyzed reliably.
Portrait images are currently not supported. Imported portrait images are automatically rotated. This is necessary because phones sometimes misinterpret the image orientation when taking photos from above.
To keep image processing fast, especially on less powerful phones, GammonSnap does not search the entire image for the doubling cube.
The cube is only searched for in common areas around the detected board. These areas are to the left and right of the board. A cube placed above or below the board may not be detected.
If the cube is placed on the board, GammonSnap searches for it mainly in the middle third of the board.
For checker play, GammonSnap uses the side of the board where the dice are detected to determine the active player. If the dice are detected on the right side, it is considered the bottom player's turn.
For cube decisions, GammonSnap uses heuristics to determine whose turn it is. For example, it may look at factors such as who is ahead in the race or whether a player has checkers on the bar. These heuristics have limits. This is especially true in close bear-off positions, where both players may have a strong cube depending on whose turn it is.
If the active player was detected incorrectly, you can correct it manually before starting the analysis.
You can edit every position manually if something was not detected correctly or if you want to see the evaluation for a different position.
To start editing, tap the edit button on the right side of the backgammon board, slightly below the middle. The icon looks like a pencil.
After tapping the button, additional controls appear on the board. You can tap the backgammon points to add or remove checkers. On the side where the cube is shown, two transparent cubes appear. You can use them to change the cube position and cube value.
When you are done, tap the icon again. It now appears as a save icon and saves the edited position. If you start an evaluation, the position is saved automatically, even if you did not tap the save icon first.
To change the match score, tap the match score view. A separate dialog will open. For convenience, you can also tap the match score without entering edit mode first.
One way to do this is from outside the app. Open your preferred gallery app, select multiple images, and use the share function. GammonSnap should appear in the list of available apps. After selecting GammonSnap, the app will open and start processing the images.
You can also open your image gallery from inside GammonSnap. However, not every gallery app supports selecting multiple images when it is opened from another app. If your selected gallery app only allows you to choose one image, try another gallery app or use the sharing method described above.
At the moment, there are no plans for an iOS version of GammonSnap.
GammonSnap currently uses 2-ply evaluations for the regular analysis.
Higher-ply settings take significantly longer to calculate. Using them for every position would make the app feel much slower and would not provide a good user experience.
However, adding an option to analyze selected positions with higher-ply settings is being considered for a future version.
Image processing runs locally on your device. When you analyze a position, the image itself stays on your device.
If you request an evaluation, only the corresponding XGID is sent to the server.
The only exception is when you manually report an image that was misdetected. In that case, the image is uploaded so it can be reviewed and used to improve the detection.
