- From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
- Date: Fri, 12 Jun 2009 21:10:25 +0200
- To: www-svg@w3.org, vbs85@gmx.de
Hello, just my personal observations: http://www.w3.org/TR/SVG11/coords.html#ObjectBoundingBox [ 'filter' primitiveUnits="objectBoundingBox": Indicates that the various length values within the filter primitives represent fractions or percentages of the bounding box of the element to which the filter is applied. ] Therefore these are never pixels. Because it is defined dx = "<number>" and number has no 'unit' like '%' : http://www.w3.org/TR/SVG11/types.html#DataTypeNumber therefore this attribute can only be used to provide a fraction of the width of the boundingBox. Therefore, if the boundingBox has a width of 100px, dx = "0.25" means 25px because 100px * 0.25 = 25px But indeed the cited text above may create some confusion and may lead to another interpretation, that the number means percentages and the 'unit' is implied, then the calculation is 100px * 0.25% = 100px * 0.25/100 = 0.25px. However, because there is no possibility for authors to distinguish between percentage and a fraction with only providing a number, the second interpretation is wrong, but a clarification could be useful in the next specification. For example the SVG tiny 1.2 specification notes only fractions for objectBoundingBox (but it has no filter an not many possibilities to specify percentages in general). The new filter draft talks about fractions and percentages too: http://www.w3.org/TR/2007/WD-SVGFilter12-20070501/#FilterElementPrimitiveUnitsAttribute but dx and dy are still numbers: http://www.w3.org/TR/2007/WD-SVGFilter12-20070501/#feOffsetElement therefore with this draft no change, but there is no new draft concerning the definition of the boundingBox for the full 1.2 profile currently...
Received on Friday, 12 June 2009 18:04:48 UTC