Chess By Blog

0 that adds graphical chess

functionality to your WordPress blog. It lets you do several things:

• PGN (Portable Game Notation) inserted into your post body will be

displayed as a graphical board, inline in the browser. The client side

code was written using the Google Web Toolkit (GWT), resulting in

Javascript (no Java required) that has been tested in Internet

Explorer 6-9, Mozilla/Firefox, and Safari. The graphical look of

the chessboard is controlled by themes, and can be easily controlled

in the management panel for the plugin.

• The board supports interactive play directly in the browser, in a

mode which does not update the post body. All rules of chess are

supported, include en passant, castling, and pawn promotion. This can

be used to present chess problems for readers to work through.

• Chess By Blog also supports a persistent game played between two

players, hence the name of the plugin. Readers that have edit

permissions on a post can take turns moving pieces, with the state of

the board saving to the WordPress database between moves. The plugin

uses WordPress and PHP security features to ensure that only moves

that come from the client chessboard code can update the database.

Chess By Blog is free software, distributed under the Expat license (a

php).

Usage

The plugin adds a “Chess By Blog” to the Quicktag panel that appears

when you edit or write a new post. (Unfortunately, at this time there

) Clicking the button

will pop open a new window which allows you to create a new chess

board. The fields of this board correspond almost directly to the

seven required tags of Portable Game Notation. For the purposes of the

plugin, all fields are optional; accepting the defaults will result in

code inserted into your post which will create an empty, closed

board. There are three types of boards that can be set up:

-

Static, non playable board

A static, non playable board can be created by leaving the

“WordPress ID” blank and by inserting algebraic move notation in

the Movelist field. Note that for speed reasons, the input

(particularly pawn moves) isn’t fully error checked by the

client code.

-

Playable, non-persistent board

An interactive, non-persistent board can be created by leaving the

e. “*”). Algebraic move

notation can be optionally inserted in the move text to set up the

board. Note that when the board is played interactively, full

validation of each move is performed. This mode is ideal for

presenting chess problems that can be worked through by readers.

-

Playable, persistent board

An interactive and persistent board can be created by selecting

blog users for the White and Black players. These should

correspond to the usernames of users of your blog who have at

least Subscriber Roles.

Alternately, you can forego the usage of the Quicktags button and

insert PGN directly, enclosed in “div class=”CBB-board” tags. The

client code will treat standard PGN as a static, non playable

board. Playable boards can be created by inserting [CBBWhiteId] and

[CBBBlackId] PGN tags with values as described above.

PGN support

Chess By Blog fully supports the seven standard PGN tags. Comments

enclosed with curly braces are preserved, and will be shown at the top

of the game log table when the corresponding move is highlighted. In

addition, the FEN and JsCom (only the “startply” command is

recognized) tags are both supported, allowing specification of the

initial board layout. As an example of the JsCom tag, specifying

[JsCom “startply 5”]

will preposition the board after White’s 3rd move.

Chess variant support

Chess By Blog fully supports FEN (Forsythe-Edwards Notation) via the

“FEN” tag in PGN. This allows specification of the initial board

layout. It also allows for handling of some chess variants.

Fischer Random Chess (or Chess960) is directly supported. The initial

layout of the pieces must be specified via a FEN tag. Castling is

supported correctly for this variant.

Capablanca chess is directly supported. The layout of the board must

be specified via a FEN tag, using “A” or “a” for the Archbishop and

“C” or “c” for the Chancellor; a 8×10 piece layout must be specified

as well.

There is limited support for arbitrary board sizes. Castling is

handled by always moving the King to the ‘c’ file if castling on the a

side, or the file to the left of the rightmost file if castling on the

other side; the Rook is always moved to the inner square. This

supports Fischer Random Chess and Capablanca Random Chess, but does

not support other variants. In addition, en passant always assumes the

pawns start on the 3rd rank.

Customization

The look of the client side code is controlled by themes, which live

under chess-by-blog/themes. A new theme can be created by adding a

css”.

This style sheet should contain the same classes as shown in the

default theme. In addition, there is a requirement that the CBB-square

and CBB-button contain width, height, and min-height attributes with

explicit pixel sizes. The client side code needs these in order to

correctly infer the sizes of chessboard squares and buttons.

Building the client side code

This step is optional, but if you need to make fundamental changes to

the code that can’t covered by changes to CSS, you’ll need to edit

the Java source files in src/org/levork/gwt.

The client side code is Javascript which lives in the chess-by-blog

subdirectory, compiled from Java using the Google Web Toolkit. To

build this yourself, you will need to have the Google Web Toolkit

7), after which the entire src directory

can be copied into your Google Web Toolkit folder. It is then

recommended that you run

ChessByBlog

xml script necessary to compile using

ant. Running ‘ant build’ will compile the project into the

subdirectory war/chessbyblog. The files with cache in their name are

the Javascript files; these go in wp-content/plugins/chess-by-blog

(and the old ones should be deleted, most of them will have different

names).

Known issues

• Switching from the code to visual editor may wreak havoc on the

div tags, despite the tags being protected by pre tags. This is an

issue with the visual editor.

• Internet Explorer may have issues with the preview of new themes in

the management panel.

• There are some broken themes out there that will not work with this

plugin. In particular, if the theme does not make a call to

php, the Chess By Blog plugin will not be able

to emit the necessary lines of HTML that invoke the Javascript

code. (That theme may also break other plugins, and is definitely a

) You may be able to fix this by inserting the necessary

inserting:

at the beginning of the file.