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## [ontolog-forum] 2D drawing primitives (was: Foundation Ontology Primitiv

 To: "[ontolog-forum]" Duane Nickull Wed, 3 Feb 2010 09:27:13 -0800
 (note: changed heading for discussions related to 2D drawing primitives to allow others to filter messages) Sean: This is really great insight.  It got me thinking about the issue from a different perspective.  For a computer graphics person or developer, a point is often a single pixel whereby conceptually for an ontologist, you are quite correct in noting that it is a zero radius concept.    The people at my company (adobe) who work on Flex came up with the 5 basic drawing primitives, all based on a pixelated environment (point, fill, line (lines can have arcs in this case), ellipse and rectangle.  The line class is abstract but when sub-typed, has methods such as “lineTo(coord)” which can really be used to make any other shape.  Since a line itself could be expressed as an array of points, the point is truly the primitive here. Extending the thought, a line with an arc/curvature potential can be used to draw a circle or an ellipse if the line starts and ends at the same place.  How could I have missed this before???  It surprises me that just about every programming language with a graphics package has not adopted the ontological perspective on 2D drawing primitives. I love the Ontolog forum!! Duane On 2/3/10 5:14 AM, "sean barker" wrote: Duane Actually, circles, lines and points are all the same primitive - half-spaces of the plane: lines have zero curvature, points zero radius, and circles have finite radius and finite curvature. An ellipse is a circle after linear transformation. A triangle is the intersection of three linear halfspaces. BTW, point is not obviously a primitive, in the sense there are several different flavours of point - a 2D point is not the same as a 3D point, and a point in homogeneous co-ordinates is not quite the same as one in Cartesian co-ordinates. This is before you get to the more esoteric end of things, such a duality theory and geometry over algebraic systems other than the real numbers. I believe there is also a more generalised concept of a point called a turbine. I'm not sure I can think of any more concrete example of the claim that an ontology is viewpoint specific Sean Barker Bristol   From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Duane Nickull Sent: 02 February 2010 19:54 To: [ontolog-forum] Subject: Re: [ontolog-forum] Foundation Ontology Primitives                     *** WARNING ***   This message has originated outside your organisation,   either from an external partner or the Global Internet.       Keep this in mind if you answer this message. Inline: On 2/2/10 11:43 AM, "Matthew West" wrote: >  I hope that it will not actually be  necessary to try to precisely > define > the borderline between  primitive and non-primitive. A concept is primitive if it cannot be  completely defined in terms of concepts you already have  defined. Most OO programming languages are structured this way.  If there is any way to build such a concept with another class, then refactoring is often used. Take drawing primitives as an example.  There is one base primitive which might be “coordinate”.  This corresponds to a specific X,Y pair.  This is abstract so at this point it ignores all pixel resolutions etc but could generally taken to be based on a pixel grid. The next level down would be some primitive shapes.  Candidates might be Line, Circle, Ellipse, Rectangle, Square etc.  On closer examination, circle can be stated to be a specialized type of ellipse (one with a constant radius value) and a square can be declared as a specialized type of rectangle (one with equal side lengths within a fixed unit of precision, usually the pixel resolution when implemented).  Line might also be a candidate for rectangle (a rectangle with height:width ratio exceeding certain limits) but lines could also carry the added property of an arc or path.  Therefore the true primitives might be coordinate (or point), line, ellipse and rectangle.  This represents a context of pixelated screens however.  In vector graphics (SVG et al) the primitives may be different. A triangle then presents a test.  Is it another primitive of is it a specialized type of one of the existing graphic primitives.  One could create another primitive called “fill” that takes parameters of a “boundary” expressed in terms of lines.  This could then make up all other shapes such as polygon, triangle, star, etc.. Duane --- Adobe LiveCycle Enterprise Architecture - http://www.adobe.com/products/livecycle/ My TV Show - http://tv.adobe.com/show/duanes-world/ My Blog – http://technoracle.blogspot.com/ My Band – http://22ndcenturyofficial.com/ Twitter – http://twitter.com/duanechaos --- Adobe LiveCycle Enterprise Architecture - http://www.adobe.com/products/livecycle/ My TV Show - http://tv.adobe.com/show/duanes-world/ My Blog – http://technoracle.blogspot.com/ My Band – http://22ndcenturyofficial.com/ Twitter – http://twitter.com/duanechaos ``` _________________________________________________________________ Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/ Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx Shared Files: http://ontolog.cim3.net/file/ Community Wiki: http://ontolog.cim3.net/wiki/ To join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx    (01) ```
 Current Thread Re: [ontolog-forum] Foundation Ontology Primitives, sean barker Re: [ontolog-forum] Foundation Ontology Primitives, John F. Sowa Re: [ontolog-forum] Foundation Ontology Primitives, Patrick Cassidy Re: [ontolog-forum] Foundation Ontology Primitives, Matthew West Re: [ontolog-forum] Foundation Ontology Primitives, Ali Hashemi Re: [ontolog-forum] Foundation Ontology Primitives, Patrick Cassidy Re: [ontolog-forum] Foundation Ontology Primitives, Duane Nickull Re: [ontolog-forum] Structure of an FO consortium?, Patrick Cassidy Re: [ontolog-forum] Foundation Ontology Primitives, AzamatAbdoullaev [ontolog-forum] 2D drawing primitives (was: Foundation Ontology Primitives), Duane Nickull <= [ontolog-forum] Foundation Ontology primitives, FERENC KOVACS Re: [ontolog-forum] Foundation Ontology primitives, AzamatAbdoullaev Re: [ontolog-forum] Foundation Ontology primitives, Rich Cooper [ontolog-forum] Foundation Ontology Primitives, FERENC KOVACS