Re: Proposition on advanced URL features

Peter Paul Sint (sint@oeaw.ac.at)
Thu, 30 Nov 1995 05:41:48 -0100


Message-Id: <v0153050eace2fe824c08@[193.170.88.66]>
Date: Thu, 30 Nov 1995 05:41:48 -0100
To: tm@rasips1.rasip.etf.hr (Mirsad Todorovac)
From: sint@oeaw.ac.at (Peter Paul Sint)
Subject: Re: Proposition on advanced URL features
Cc: uri@bunyip.com

To tm@rasips1.rasip.etf.hr   :
This is the definition of some 'fragments' in Hyper-G
Not quite http but near enough for our pupose (HTF Hyper-G Text Format).
Advantage: it is really implemented and works.
I received it from  Frank Kappe <fkappe@iicm.tu-graz.ac.at>, who is the main
architect of Hyper-G., Could be adapted to the notation reported by Roy T.
Fielding's <fielding@avron.ICS.UCI.EDU>

Sint Peter-Paul <PeterPaul.Sint@oeaw.ac.at> :

...
>Unter der Collection "Hyper-G Technical Documentation"
>(http://hyperg.iicm.tu-graz.ac.at/technical) findet sich dieses
>Dokument:
>
>
>2nd August 1995
>
>                Hyper-G Anchor Specification
>
>                              Version 1.0
>
>                            Keith Andrews
>
>1. Introduction
>
>This document describes valid formats for Hyper-G anchors, as found in the
>Position field of
>anchor objects in the database, and created and recognised by Hyper-G
>clients. Note that
>the Position field is always a single line, it may not contain embedded
>newlines.
>
>The following general conventions apply:
>
>    1.All fields are human-readable ASCII strings.
>    2.Integers and reals are encoded in C notation:
>
>      Integers:  123  0x7B
>      Reals:     6.5  -0.62537  23.6e12
>
>2. Default Anchors (All Document Types)
>
>Default source anchors should not be used.
>Default destination anchors are defined as follows:
>
>Text
>
>entire document (scrolled to top)
>Image
>      entire document
>Film
>      entire document (from beginning)
>Audio
>      entire document (from beginning)
>Scene
>      default camera position
>PostScript
>      first page
>
>The database does not maintain an anchor object for a default destination;
>the id of the
>destination document is entered in the source anchor. Hyper-G clients
>should represent a
>default destination anchor with the word Default, as in:
>
>  Position: Default
>
>3. Text Anchors
>
>
>Position: start end
>
>where start and end are (inclusive) integer byte offsets in the text.
>
>Examples
>
>Position: 123 127
>Position: 0x5b 0x19c
>
>4. Image Anchors
>
>
>Position: Rect x0 y0 x1 y1
>Position: Circle x y r
>Position: Ellipse x0 y0 x1 y1
>Position: Polygon x0 y0, x1 y1, ..., xn yn
>
>For Rect, x0 y0 specifies the lower left corner, x1 y1 the upper right
>corner of the rectangle.
>
>For Circle, x y specify the centre of the circle, r specifies its radius
>(in terms of extent along
>the X axis).
>
>For Ellipse, x0 y0 specifies the lower left corner, x1 y1 the upper right
>corner of the bounding
>rectangle of the ellipse (whose conjugate diameters are assumed to be
>aligned horizontally
>and vertically).
>
>For Polygon, xi yi are the vertices of a (general) polygon.
>
>Coordinates are real numbers in a normalised coordinate space from lower
>left corner of image
>(0,0), to upper right corner of image (1,1).
>
>Examples
>
>Position: Rect 0.16666 0.40877 0.77567 0.78966
>Position: Circle 0.4 0.4 0.321
>Position: Ellipse 0.16666 0.40877 0.77567 0.78966
>Position: Polygon 0.13 0.877, 0.94 0.96, 0.979 0.48, 0.83 0.83, 0.23 0.9,
>0.07 0.93
>
>5. Film Anchors
>
>
>Position: Rect interp n : f1 x0 y0 x1 y1, f2 x0 y0 x1 y1, ..., fn x0 y0 x1 y1
>Position: Circle interp n : f1 x y r, f2 x y r, ..., fn x y r
>Position: Ellipse interp n : f1 x0 y0 x1 y1, f2 x0 y0 x1 y1, ..., fn x0 y0
>x1 y1
>
>interp takes either the values Linear or Spline and specifies the kind of
>anchor interpolation
>used.
>
>n (>=1) is an integer specifying the number of keyframes
>
>fi defines the frame number of keyframe i.
>
>x0 y0 x1 y1 specify the position of a rectangular anchor at keyframe i,
>
>x y r specify the position of a circular anchor at keyframe i (as for
>Image anchors).
>
>x0 y0 x1 y1 specify the bounding rectangle of the ellipse (whose conjugate
>diameters are
>assumed to be aligned horizontally and vertically) at keyframe i.
>
>Example
>
>Position: Rect Linear 3 :
>          125 0.16666 0.40877 0.77567 0.78966,
>          150 0.10000 0.40000 0.70000 0.70000,
>          166 0.16666 0.40877 0.77567 0.78966
>
>Note that this is one long line, newlines are not allowed in the middle of
>fields.
>
>6. Audio Anchors
>
>
>Position: start end
>
>start and end are real number offsets in seconds from the start of the audio.
>
>Examples
>
>Position: 0 1.5           [first 1.5 secs]
>Position: 31.05 31.55     [half a second]
>
>7. Scene Anchors
>
>a) Source
>
>
>Position: object
>Position: object/group
>
>object refers to object in the scene and not database objects. The object
>can be specified by
>name (string) or as "Object N" where N is the number (integer) of the
>object. Object names
>and numbers are defined in the scene definition file.
>
>group (string) refers to a named part of an object, i.e. a group of
>polygons. If no group is given,
>the anchor affects the whole object. Group names are defined in the scene
>definition file.
>
>Examples
>
>Position:      Object 27
>Position:      globe/africa
>
>b) Destination
>
>
>Position: (px, py, pz) (lx, ly, lz)
>
>(px, py, pz) defines the camera position (3 reals), (lx, ly, lz) defines a
>"lookat point" in the
>scene (3 reals).
>
>Example
>
>Position: (0.1, 0.2, 0.3) (4.0, 5.0, 6.0)
>
>8. PostScript Anchors
>
>
>Position: p:x,y,w,h
>
>p is the page number (integer >= 1)
>
>x,y,w,h are the upper, left, width, and height integer coordinates of a
>rectangle, based on a
>specific page calculated at 300dpi. As is typical for PostScript, the
>coordinates system has its
>origin at the top left of the page.
>
>Example
>
>Position: 2:300,300,600,750    [page 2, 1 inch in from top left]