| Author: | Benja Fallenstein |
|---|---|
| Date-Created: | 2003-07-03 |
| Last-Modified: | 2003-07-28 |
| Revision: | 1.4 |
| Status: | Incomplete |
| Scope: | Minor |
| Type: | Interface |
The Canvas2D vocabulary (http://fenfire.org/rdf-v/2003/05/canvas2d) specifies properties and classes for placing things on 2D canvases.
This vocabulary does not, however, take into account that a node's coordinates on some paper are not properties of that node; e.g., when we have a node "The Fenfire system," then this system does not have x coordinate 145 and y coordinate -32; rather, a rendition of the node representing the Fenfire system is placed at these coordinates.
The failure of taking this into account means that there cannot be transclusions of a node, i.e. one node cannot be placed on multiple papers; in Fenfire, transclusion must be supported for anything, i.e., whenever some thing is in a "context," it must be possible to place it in more than one context.
In order to make nodes transcludable, the vocabulary must be changed.
Should the definition of the existing namespace be changed, or should we create a new namespace?
RESOLVED: New namespace. Three out of four URIs in the namespace cannot be used with their existing definition (and changing the definition of an existing URI is bad practice); retaining the last URI (#Canvas) simply isn't worth it.
Do we need a converter?
RESOLVED: As save/load hasn't worked for FenPDF so far, we can expect that nobody has data in it yet; unless somebody speaks up, we'll assume we need no converter.
[tjl] Couldn't we just resolve this by a more generic facility: a clone property. Then, when looking for the node's content you'd always follow the clone property.
This would work for other things beside just nodes on canvases.
[tjl] Where does the terminology ":Domain:", &c come from? Is there a standard somewhere that specifies these?
Create a new namespace, http://fenfire.org/rdf-v/2003/07/canvas2d-bis, containing the following names and definitions:
A transclusion of a node onto a canvas. This represents one instance of a node on a specific canvas. The node transcluded is related to this node through the #transcludes property.
Having this is necessary so that a single node can be placed on more than one canvas.
A property relating a canvas to the node transclusions it contains.
| Domain: | #Canvas |
|---|---|
| Range: | #NodeOnCanvas |
| Cardinality: | 1:n |
A property relating a transclusion to the node it is a transclusion of.
| Domain: | #NodeOnCanvas |
|---|---|
| Range: | #Resource |
| Cardinality: | n:1 |
The x and y coordinates of a node on a canvas. Note that these are the default coordinate properties: later on, we might make it possible for a Canvas2D to define its own coordinate attributes, which would take use close to Ted's floating world ideas.
The objects in this namespace are literals of type xsd:double.
| Domain: | #NodeOnCanvas |
|---|---|
| Range: | xsd:double |
| Cardinality: | n:1 |
Change org.fenfire.vocab.CANVAS2D to use this namespace.
Make the necessary changes in the other code so that the rules of this namespace are respected; in particular, the coordinate literals need to be of type xsd:double.
- Benja