BesoGo

Embeddable SGF player for the game of Go (aka Weiqi, Baduk)

Written in JavaScript, CSS, and HTML5, with no dependencies on other libraries

Free software released under the MIT License. Some bundled assets are copyright by other authors and available under Creative Commons licensing terms. See "Copying and License" section for further details.

User Notes

BesoGo can be used as a web-based SGF editor, an embeddable SGF viewer, or a board diagram renderer

Online usage

SGF editor based on the latest code snapshot at https://yewang.github.io/besogo/testing.html

With realistic board rendering https://yewang.github.io/besogo/testing.html?theme=wood&realstones=on

Other experimental themes include:

• https://yewang.github.io/besogo/testing.html?theme=bold
• https://yewang.github.io/besogo/testing.html?theme=book
• https://yewang.github.io/besogo/testing.html?theme=dark

SGF editor based on the latest release (lagging behind the latest snapshot) at https://yewang.github.io/besogo/stable.html

Offline usage

Download the source distribution and open testing.html

Navigation key bindings

• left previous node
• right next node
• shift+left previous branching node
• page up jump back 10 nodes
• page down jump forward 10 nodes
• home jump to first node
• end jump to last node
• delete remove current branch

Shift-clicking with the auto-move/navigate tool will jump to the move that plays at that point

When entering moves, overwrite, suicide, and basic ko moves are not allowed, but can be enabled by holding down ctrl while clicking

BesoGo supports the SGF standard for Go game records. BesoGo should always output SGF files that comply with the standard (besides the exceptions listed below). BesoGo permissively imports SGF file input, allowing many common SGF syntax errors, while attempting to fix any issues and converting to valid SGF on output.

Exceptions in SGF standard support

• Some properties are unsupported and ignored:
  • Time left OB, OW, BL, WL
  • Move annotations BM, DO, IT, TE
  • Control annotations KO, MN, PL
  • Some general annotations DM, GB, GW, HO, N , UC, V
  • Some markup AR, LN, TB, TW, DD, FG, PM, VW
• No special validation is performed on game info properties: PB, BR, BT, PW, WR, WT, HA, KM, RU, TM, OT, DT, EV, GN, PC, RO, ON, RE, AN, CP, SO, US. All are merely treated as "simple text" (all whitespace converted to spaces), except for GC which is treated as text (allowing new lines and spaces).
• Some root properties (FF, GM, CA, AP) are ignored on file input and set to fixed values on output.

Web Dev Guide

See https://yewang.github.io/besogo/ and https://yewang.github.io/besogo/fixedSize.html for some examples of how to embed BesoGo. See https://yewang.github.io/besogo/testing.html for an example full window interface for the editor.

To embed BesoGo editor/viewer in your website

1. Link the style sheet css/besogo.css and one of the css/board-*.css sheets, which select different board themes (simple, flat, book, dark, wood, etc.). These sheets provide essential rendering parameters and can be modified to customize the layout and style.
2. Include the combined and minified javascript file besogo-all-min.js.
3. Add divs with the class besogo-editor, besogo-viewer, or besogo-diagram, e.g.,

   <div class="besogo-editor"></div>
   <div class="besogo-viewer" sgf="gameRecord.sgf"></div>
   <div class="besogo-diagram" panels="comment">
   (;FF[4]GM[1]SZ[9]AB[bb:dd]AW[ee][ff][gg]
   C[This diagram shows a 9x9 board with 9 black stones and 3 white stones placed on it.
   Be sure to properly escape HTML special characters such as &gt;, &lt;, etc.])</div>
   

4. Call the auto-initialization function besogo.autoInit() to create widgets for the above divs.

The contents of the div should either be empty or contain SGF text. If SGF text is detected (by starting with "(;", ignoring whitespace), it will be loaded into BesoGo. BesoGo will remove all children from the div and then insert sub-divs building up the GUI.

Security Warning: If your site inserts user-input SGF text directly into the inner HTML of a div, remember to escape any HTML special characters ("<", ">", "&") to avoid XSS vulnerabilities. BesoGo will properly load the intended characters. This is not a security vulnerability within BesoGo, but rather a reminder to use secure practices in your surrounding code.

Options settable via div attributes

• sgf sets the URL (from same domain or server with CORS enabled) of the SGF file to load. If an URL is provided, BesoGo ignores the text within the div.
• size sets the size of the empty board loaded if no SGF text or URL is provided. Square sizes can be specified by a single number (e.g., "19", "13") and rectangular sizes are specified by two numbers separated by a colon (e.g., "9:15"). Sizes from "1:1" to "52:52" are supported.
• realstones sets board rendering to use realistic stone images if set to a truthy value. Otherwise, defaults to flat SVG stones.
• shadows selects whether shadows will be added beneath the stones. If omitted or set to auto, shadows will be added for realistic stones, but not for SVG stones. If set to off, shadows will not be added. If set to any other truthy value, shadows will always be added.
• coord sets the initial coordinate system, which is by default none, and can be choosen from the following options:
  • none no coordinate labels
  • western chess-style coordinates using numbers and letters
  • eastern coordinates using numbers and CJK symbols
  • numeric coordinates using only numbers
  • corner corner-relative system using numbers and letters
  • eastcor corner-relative system using numbers and CJK symbols
• panels plus-separated list of which GUI elements are added in the GUI. The following panels are supported:
  • control navigation control buttons
  • names player names, ranks, and captures
  • comment comments and game info
  • tool editing tool selector buttons
  • tree game tree visualization
  • file save, load, and new board buttons
• tool sets the selected tool.
• variants sets the variant style, formatted as number 0-3 according to SGF standard.
• path string to set the initial position in the game tree of the loaded SGF. The letter N or n sets to next mode. The letter B or b sets to branch mode. One or more digits specifies the number of nodes to move forward always taking the first child (when in next mode), or the child to select (when in branch mode). All other characters are ignored but used to separate numbers. Next is the default mode. Zero in branch mode selects the last child. Examples:
  • 20 moves to the 21st node in the mainline of the game tree, which typically contains the 20th move assuming no move in the root and no empty/setup nodes besides the root.
  • n5b1b1-1z1-1n10 does the same as 20, but overly verbose and redundant.
  • b2,3,0,1 navigates following the 2nd child, 3rd child, last child, and first child over four steps.
• nokeys turns off navigation key bindings if set to a truthy value. Otherwise, by default, navigation keys are enabled and the tabindex attribute of the container div is set to 0 (to enable keypress focus), if not already set.
• nowheel turns off mousewheel navigation if set to a truthy value. Otherwise, by default, mousewheel navigation is enabled.
• resize sets the resizing behavior of the widget, defaulting to auto if not set, with the following options:
  • auto is the default responsive resizing behavior, which depends on the settings of the following companion parameters
    • orient can be set to landscape, portrait, auto or view
      • portrait or landscape fixes the orientation of the widget as specified
      • auto is the default behavior, which switches from landscape to portrait if the parent container width is less than transwidth
      • view is the same as auto, but also switches from landscape to portrait if the parent container width is less than viewport height
    • transwidth sets the width to transition from landscape to portrait for auto and view orientation modes, defaulting 600 pixels if not set
    • maxwidth sets a limit on the maximum width, otherwise the widget will fill the width of the parent container if omitted
    • portratio sets the height-to-width ratio for portrait mode, expressed as a percentage. Defaults to 200% if not set. If set to a truthy value that converts to NaN, then the GUI panels will have a compact automatic height.
    • landratio sets the width-to-height ratio for landscape mode, expressed as a percentage. Defaults to 200% if not set.
    • minpanelswidth sets the smallest width for the GUI panels in landscape mode, where the board and widget height would be shrunk to ensure that this minimum is met, defaulting to 350 pixels if not set
    • minpanelsheight sets the smallest height for the GUI panels in portrait mode (if height is computed using portratio), defaulting to 400 pixels if not set
  • fill is another responsive resizing behavior designed for filling and only using the entire window. It toggles between portrait and landscape modes automatically depending on the aspect ratio. It also makes use of the minpanelswidth and minpanelsheight to ensure that the panels are visible if needed and the aspect ratio is too squarish.
  • fixed requires the width and height of the container div to be set, as they will be accordingly
  • none or any other truthy value that is not auto or fixed disables all resizing

Code Doc

Everything is (or at