NOTE:
This project is no longer being maintained: it was developed for my masters thesis, which was completed in early 1997. I still, however, welcome any questions or comments that people may have.

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iHTML Python Language

Standard ihDoc Module

The ihDoc module provides a standard interface for document programs, i.e. programs connected to an HTML document through an <OBJECT> tag that occurs in the document's <HEAD>. These programs will typically be written as a subclass of this class, named ihMain.

Exported Values

There are no global values defined by this module.

Exported Exceptions

There are no global exceptions defined by this module.

Exported Functions

There are no global functions defined by this module.

Exported Types

There are no global types defined by this module.

Exported Classes

`Document`

The Document is the main definition of the document program. It provides services for manipulating and interacting with the global document environment, and base-line functionality needed by all document programs. When a document program is executed, its main entry point -- named ihMain -- is expected to return an instance of a class that is a subclass of Document and implements the desired program logic.

Hierarchy

Superclass: none.
Subclasses: none.

Methods

__init__(self, ...)

Summary

Initialize class instance and attach to the browser-side document.

Arguments

Argument dictionary must be passed.

Result

A new instance of the class.

Bugs

The connection from the iHTML library to the user document is not made until after this function returns; this needs to be done during the initialization itself.

Reformat should not need to be called to display the document; this seriously breaks progressive displays. Instead, we should introduce a <CALL> tag, to insert dynamically constructed markup into the document, and a document message that is send when the entire document has been fetched and parsed.

See Also

Document tutorial.

Description

When a new Document instance is created, this initialization method does the low-level setup required by the iHTML library. While no arguments are specifically defined by this class, the argument dictionary handed to the ihMain entry must pass them up to this initialization function. This is typically accomplished with a program structure such as such as:

class ihMain(ihDoc.Document):

    def __init__(self,**args):

        apply(ihDoc.Document.__init__,(self,),args)

In all cases, this super-class initialization must be performed before any other actions are taken.

Reformat(self)

Summary: Make the browser document re-examine and display the current HTML parse tree.
Arguments: none.
Result: nothing.
Bugs: As of the 0.4 version of iHTML under Mosaic, calling this function a second time with a changed display will result in a crash.
See Also: ihMarkup module.
Description: This method will always be called at least once -- it must be called during __init__() to display the initial page to the user. Typically, the program will do whatever initial construction of that page that needs to be done before it is "presentable", and then this function is called to display it.

ShowProgress(self, text)

Summary

Display progress report to user.

Arguments

text: A string containing the text to display.

Result

nothing.

Description

Calling this function displays the given to text to the user in the form of a progress report. This should be used to, for example, tell the user that data is being sent over the network. The exact way this information is presented to the user is browser-dependent.

ShowLink(self, link)

Summary

Tell the user about a hyper-link.

Arguments

link: A string of text which should be displayed about the link.

Result

nothing.

Description

This displays to the user information about a link that is "in focus" -- e.g., the cursor is positioned over it. The exact way this information is presented to the user is browser-dependent.

AddHandler(self, func)

Summary

Add an event handler to the document.

Arguments

func: A function to call when processing document events. It is called with two parameters: this Document class, and the Event that occurred.

Result

nothing.

Bugs

The first argument handed to the function is actually the library's low-level document object and not the user's class.

See Also

Module ihEvent.

Description

This method adds a new function to the Document's handler list. This is a list of functions that are called whenever a document-level event occurs; each function in the list is successively called until one of them returns a value that is something besides None.

All events sent to this handler are document-class events; this includes such things as document resizing, scrolling, etc. There will hopefully soon be a more complete set of events, including keypresses, mouse movement, mouse buttons, hyperlinks, etc.

RemHandler(self, func)

Summary

Remove the given function from the document's list of handlers.

Arguments

func: Function which was previously added through AddHandler()

Result

nothing.

Bugs

This function is currently not implemented.

Members

Capabilities

A set of information about the capability of the browser the program is running under. Retrieving an attribute returns in integer representing that capability; 0 means the browser doesn't have it and 1 means it does. Some capabilities define other values. The currently defined capability attributes are:

forms: Does this browser support HTML forms?
sockets: Are socket connections supported?
comp_mosaic: Does the browser support the basic Mosaic feature-set?
disp_text: Does the browser support text display?
disp_graphics: Does the browser support graphical display?
disp_mono: Does the browser support monochrome graphics?
disp_color: Does the browser support color graphics? The return value is the number of pens supported.
disp_true: Does the browser support a true-color display? The return value is the bit depth per pixel.

VisHTMLTree

The current HTML parse tree representing the document.

ViewTop

The top of the user's view within the entire document, in pixels.

ViewBottom

The bottom of the user's view within the entire document, in pixels.

ViewLeft

The left side of the user's view within the entire document, in pixels.

ViewRight

The right side of the user's view within the entire document, in pixels.

ViewHeight

The amount of the document visible to the user at any one time, in pixels.

ViewWidth

The amount of the document visible to the user at any one time, in pixels

DocHeight

The total height of the current document, in pixels.

DocWidth

The total width of the current document, in pixels.

Description

Current problems:

All of the document member variables are not connected to the low-level document, and thus do not represent the current state of the document. In the next release, they will probably change to methods.
Changing the view information (to, for example, scroll through the document) is not yet supported

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_________.oo_Q_Q_oo.____________________________________________

Dianne Kyra Hackborn <hackbod@angryredplanet.com>
Last modified: Fri Sep 13 06:04:32 PDT 1996

This web page and all material contained herein is Copyright (c) 1997 Dianne Hackborn, unless otherwise noted. All rights reserved.