- From: Rick <graham.rick@gmail.com>
- Date: Thu, 16 Sep 2010 11:27:35 -0400
- To: www-svg <www-svg@w3.org>
- Message-ID: <AANLkTi=DGa16nN9dJe3NSYpB8ZexL6pmZJNBTD9VfMyA@mail.gmail.com>
On Thu, Sep 16, 2010 at 10:45 AM, Rick <graham.rick@gmail.com> wrote: > > Hello SVG Working group > > In writing a document regarding coordinate spaces for some server software, > I find that I cannot locate the definition of what constitutes an angle in > SVG. > > Also, the only place that I see it stated that vertical for a Y coordinate > is negative is in the magic flip definition for glyphs, and it seems likely > that that most excellent and useful aspect of SVG is under threat due to the > persistence of a vocal minority. > I've discovered that the inverted Y behaviour is explained in chapter 7: http://www.w3.org/TR/SVG/coords.html#InitialCoordinateSystem There is no mention there of an angle direction. > > http://www.w3.org/TR/SVG/fonts.html#SVGFontsOverview > > My thoughts are this information should be stated in the definitions for > the angle and coordinate data types in chapter 4. > > http://www.w3.org/TR/SVG/types.html#DataTypeAngle > http://www.w3.org/TR/SVG/types.html#DataTypeCoordinate > > I'm not certain that there are any concepts that require the notion of a > zero angle direction. Unrotated simple text runs left to right, but not all > text does. I can't think of a concept in SVG where an angle is not > relative. > > Nevertheless it might be useful to define what direction zero is. In GIS > it is up, in Cartesian space it is to the right. > > The following concepts are true for SVG, conflict with Cartesian concepts > (so they are not intuitive), and should be stated in the data definitions: > > - Angles are measured in a clockwise direction. > - Y ordinates increase from top to bottom. > > Please clarify this in the data type definitions. > > -- > Cheers! > Rick > > > -- Cheers! Rick Eeny, Meeny, Jelly Beanie, the spirits are about to speak! -- Bullwinkle Moose
Received on Thursday, 16 September 2010 15:28:08 UTC