Re: Detailed proposal for layered fill and stroke

Hi Amelia,

The idea of the layered fill and strokes were to follow the exact same syntax that ‘background’ uses. The same is the case for the ‘mask’ property. We want to make sure that people coming from the HTML/CSS world know how to use ‘fill’ and ’stroke’ immediately. From an implementer point of view this is the easiest way to do it as well since most parsing and style rules can be shared between these properties.

If I understand your proposal correctly, you want to provide some additional properties that help specifying certain parts of it? I am not so sure if *-paint, *-color or *-index would be useful at the beginning and suggest that we wait for initial implementations and feedback from authors. More over, *-paint and *-index should be brought to the CSS WG for review first if we decide to have these extra properties.

Greetings,
Dirk

On May 11, 2015, at 11:18 PM, Amelia Bellamy-Royds <amelia.bellamy.royds@gmail.com<mailto:amelia.bellamy.royds@gmail.com>> wrote:

Hello all,

I have written up a detailed proposal for how multiple fill and stroke paint layers could be implemented as a set of coordinating style properties:

  *   https://www.w3.org/Graphics/SVG/WG/wiki/Proposals/Layered_Paint_Properties


Please take a look and let me know what you think.

The SVG WG has committed to allowing multiple paint layers in the fill and stroke property, but there has not been much careful discussion of how it would work.  The current spec copies the syntax from CSS backgrounds with minor alterations that do not fully address the differences between paint servers and background images, or between SVG and CSS layout.

The proposal also includes practical implementation approaches for the following issues:

- How context fill and stroke colors can be used in both markers and paint servers, when those properties can themselves be layered lists of paint servers.
- How paint order of strokes, fills, and markers can be controlled when there are many layers of paint and many possible marker types.
- How authors can specify alternative object bounding boxes for paint servers, so that e.g. stroke paint can be scaled according to the stroke region.

With respect to reference bounding boxes, the proposal could also provide an easier to implement solution for clipping, masking, and filters.  Please look over it closely if you're working on one of those FX specs.  Currently there are significant inconsistencies in those specs with respect to how objectBoundingBox and userSpaceOnUse units should interact with non-SVG bounding boxes.

Best,
Amelia BR