==================
Kupu API reference
==================

Kupu can be customized in several ways: controls can be customized or
hidden using CSS, elements can be modified using TAL (modifying the
macro) and more advanced customization can be done by extending (or
modifying, although this is usually not advised) the JavaScript,
either in the macro or in seperate .js files. This document will give
a short description of how to use and extend the Kupu JavaScripts and
a reference of the public Kupu API.


How to use Kupu
===============

The KupuEditor and KupuUI objects
---------------------------------

Generally the body tag of the document will contain a call to the
initKupu function. This is the glue code of Kupu, here's where all the
objects get instantiated and tied together to form the
application. When doing large customizations, this function will
usually be overwritten or extended. The default implementation takes 1
argument (the id of the iframe it will control) and return a reference
to the core object, KupuEditor.

    kupu = initKupu("kupu-editorframe");

The KupuEditor object (in this case called 'kupu') will be the object
with which you can control the iframe, the UI and
tools. Customizations should generally not involve extending the
KupuEditor object, but rather by plugging in new tools. Usage is quite
straightforward, for a reference of the public methods see below.

The UI object holds event handlers for the toolbar buttons. This is a
core Kupu object and should generally be left untouched. The event
handlers, although the preferred method of attaching events is dynamic
from inside the objects rather then from HTML, should be attached to
the buttons from the template (this made the code a lot cleaner, it
might change in future versions though). Therefore a reference to the
UI object must be retrieved from the KupuEditor object using the
getTool method:

    kupuui = kupu.getTool('ui');

Note that the reason why this method is called getTool is that the UI
is essentially treated as a tool, an Kupu plugin (more about those 
later). The string 'ui' is the id by which the object is registered 
in initKupu. Usually the ui object and the button bindings can just 
be copied from the kupu.html file (if you don't use ZPT macros in the 
kupumacros.html file).

Tools and extending Kupu
------------------------

Tools are extensions of Kupu. A tool can be seen as a plugin in the
Kupu editor, providing additional functionality. Tools will usually be
the objects that will be extended or overridden.

A tool should usually subclass KupuTool and will usually override the
'initialize' method (which will be called when the tool is registered to
the KupuEditor object) and the updateState method (which will be
called on click and certain keyup events on the iframe so that the
state of the tool (e.g. add or edit mode) can be controlled. Events on
elements should generally be bound to the methods from inside the
tools.

The initialize method will be called with a single argument, a
reference to the editor object. The method should at least store that
reference on this. Note that if you don't override the method, the
KupuObject class provides a default implementation that does exactly
that. The updateState method will be called with 2 arguments, the
first is a reference to the current selected element and the second
the event object.  If the tool doesn't want to react to state changes,
it doesn't have to override the method: the superclass will provide a
dummy implementation.

Usually a tool will be created and registered inside initKupu,
although it can also be done from an external document or the HTML. An
object is registered to the KupuEditor object as such:

    var myTool = new MyTool();
    kupu.registerTool('my-tool', myTool);

As shown above, the getTool method of the KupuEditor object can be
used to retrieve a reference to the tool later on (so there's no need
to store a reference in the global namespace or anything).

For a nice, small example of a tool, see the PathTool in the
kupubasetools.js file. 

ToolBoxes and larger Tools
--------------------------

Most tools will both harbour functionality and stuff like event handlers 
and references to HTML elements. To make sure the tool can be used in as
much different situations as possible, it is advised to split it up in 2
pieces, one for the logic and one for the UI-related methods and 
attributes.
The standard way for doing this is using a subclass of KupuTool for the
tool and a subclass of KupuToolBox for the UI-part, and register the ToolBox
to the Tool using the registerToolBox method. It is not mandatory to use
this baseclass, not even to use registerToolBox, but it should be sufficient.

For a more complex (and useful) example of a Tool combined with a ToolBox 
see the LinkTool.

Public API
==========

Helper functions (kupuhelpers.js)
---------------------------------

Methods on KupuObject (kupueditor.js)
-------------------------------------

    registerTool(id, tool) 
        - register a tool

    getTool(id)
        - return a previously registered tool

    registerFilter(filter)
        - register a ContentFilter

    updateState(event)
        - trigger the updateState machinery

    saveDocument()
        - save the document

    prepareForm(form[, fieldid)
        - add a hidden field to form with the id fieldid (defaults
            to 'kupu'), should be called before the form is subbmited
            to make the Kupu content get sent to the server using POST.

    execCommand(command[, param])
        - perform an execCommand on the editor iframe

    getSelectedNode()
        - returns the currently selected node

    getNearestParentOfType(node, type)
        - returns the nearest parent of node (or node itself) of 
            element type
            
    getDocument()
        - returns the document object

    getInnerDocument()
        - returns the iframe.contentWindow.document

    insertNodeAtSelection(node)
        - insert a new node on the cursor location

    logMessage(message, severity)
        - log a message with the logger, message is the message to log and
            severity is an integer that can be 0 (default) for debug messages,
            1 for warnings and 2 for errors (different loggers can be plugged
            into Kupu, but a severity of 2 will usually make the logger raise
            an exception).

    getBrowserName()
        - return the name of the client browser, will return IE, Mozilla
            or raise an exception if the client uses a non-supported one.

    getXMLBody(transform)
        - transform is a Sarissa node.
          Returns the body tag (or body tags if more than one) as text.

    getHTMLBody()
        - returns the body node as text (including <body> tag). Will return all
          body nodes if there are multiple bodies.

    setHTMLBody(text)
        - sets the contents of the body to the specified HTML text
          (which should not include a body tag). If there are multiple
          bodies they are all replaced.

Methods on tools (kupubasetools.js)
-----------------------------------

    KupuTool - the baseclass for tools

        initialize(editor)
            - initialize the tool

        updateState(selectedNode, event)
            - update the state of the tool if required

        registerToolBox(id, toolbox)
            - register a ui object (ToolBox)

    KupuToolBox - the baseclass for toolboxes (view elements of tools)

        initialize(tool, editor)
            - initialize the toolbox

        updateState(selNode, event)
            - update the state of the UI according to the iframe's state

Tool implementations (depending on the complexity of the tool a tool either
    exists of a single Tool class, or of a Tool and a ToolBox class, the 
    ToolBox classes will only harbour event handlers and such so will
    therefore not be documented):

    KupuUI - the toolbar, only contains event handlers and generic button
        handlers

        basicButtonHandler(action)
            - handle a basic action like Bold or Italic

        saveButtonHandler()

        saveAndExitButtonHandler()

        cutButtonHandler()

        copyButtonHandler()

        pasteButtonHandler()
            - basic button handlers for a specific action

        setTextStyle(style)
            - set the style of the current text block

    ColorchooserTool - the color picker (part of the toolbar)

        openFgColorChooser()
            - open the colorchooser to pick a foreground color

        openHlColorChooser()
            - open the colorchooser to pick a background color

        chooseColor()
            - event handler for a click inside the colorchooser

        show()
            - show the colorchooser

        hide()
            - hide the colorchooser

        createColorChooser(table)
            - create the colorchooser and inside the table

    PropertyTool - set the title and metadata of a document

        updateProperties()
            - set the properties on the document from the form data

    LinkTool - add and edit hyperlinks

        createLink(url, type, name, target, title)
            - create a link around the current selection

        deleteLink()
            - delete the current link, if any

    ImageTool - add and edit images

        createImage(url, alttext, imgclass)
            - create an image

        setImageClass(imgclass)
            - set the class of the selected image

    TableTool - add and edit tables

        addPlainTable() 
            - add a table with default settings

        createTable(rows, cols, makeHeader, tableclass)
            - create a table

        addTableRow()
            - add a row underneath the current selected one

        delTableRow()
            - delete the current table row

        addTableColumn()
            - add a column to the right of the current one

        delTableColumn()
            - delete the current table column

        setColumnAlign()
            - set the alignment of the current column according to the form
              data

        setTableClass()
            - set the table class according to the form data

    ListTool - manage lists (part of the toolbar)

        addUnorderedList()
            - add an unordered list

        addOrderedList()
            - add an ordered list

        setUnorderedListStyle()
            - set the style of the nearest unordered list parent according to
              the form data

        setOrderedListStyle()
            - set the style of the nearest ordered list parent according to
              the form data

    ShowPathTool - show the path to the current node in the status bar

        no methods besides updateState()

Additional helper functions, objects and methods:
-------------------------------------------------

    addEventHandler(element, event, method, context)
        - bind <method> to <event> on <element>, using <context> as context
            ('this' inside the method body).

    removeEventHandler(element, event, method)
        - remove binding of <method> for <event> from <element>

    selectSelectItem(select, item)
        - select item <item> from HTML optionlist <select>

    loadDictFromXML(document, islandid)
        - load configuration values from an XML chunk

    Logger objects:

        When the KupuEditor gets initialized, it expects a logging
        object with one method (log(message, severity)) to be passed
        along as an argument. Two loggers are defined: 1 called
        DebugLogger that will alert all messages and 1 called
        PlainLogger that should be instantiated with the ids of the
        element in which debug messages will be shown and the maximum
        number of messages as arguments, that will show all debug
        messages and warnings to the debug window and will raise an
        exception for all errors.

    ContextFixer:
        
        A helper class to fix the contexts in methods when called in a
        specific way (usually when used as an event handler). In some
        cases the 'this' variable inside functions can change, this
        class helps in resetting it to the object on which the method
        is defined (and actually it can help in setting a different
        context as well, although this will not generally be
        advised). For more information see the source.

    Timer:
        
        A herlper class to overcome a problem with
        window.setTimeout(), this has the problems that it isn't
        usable to call object methods without very nasty complications
        and that it doesn't allow usage of variable references as
        arguments (both because the argument that is executed is a
        string that will be evalled in global context). For more
        information see the source.

    Array.prototype.contains(element):

        - a helper method added to the prototype of Array that will
          return true if element is in the array, false if it isn't.

    String.prototype.strip(string):

        - a helper method added to the prototype of String that strips
          all outer whitespace. The original string is not affected; a
          new instance of String is returned.
