Filter primitive subregion interpretation #1047
Description
The spec (both SVG 1.1 and the 2.0 draft) contain this half-sentence when talking about the filter primitive subregion:
the default subregion is 0%,0%,100%,100%, where as a special-case the percentages are relative to the dimensions of the [filter region]
(https://www.w3.org/TR/SVG11/filters.html#FilterEffectsRegion), thus making the the default [filter primitive subregion](https://www.w3.org/TR/SVG11/filters.html#FilterPrimitiveSubRegion) equal to the [filter region](https://www.w3.org/TR/SVG11/filters.html#FilterEffectsRegion).
It isn't entirely clear (at least to me) if this this just an awkward way of saying "the default filter primitive subregion is equal to the filter region", or if it prescibes how percentage are to be interpreted in x, y, width, height set on filter primitves.
This quick experiment:
<svg xmlns="http://www.w3.org/2000/svg" width="500" height="500"> <defs> <filter id="filter"> <feFlood flood-color='pink' x='0' y='0' width='10%' height='50'/> </filter> </defs> <rect transform="scale(2)" x='20' y="100" width="100" height="100" filter="url(#filter)" /> <rect transform="scale(2)" x='20' y="100" width="100" height="100" fill='none' stroke='black' stroke-width='1px' /> </svg>
shows that browsers and inkscape interpret the 10% relative to the viewport, not relative to the filter region.