[SOLVED] Are there other Slope types for creating glow effects in SVG?

Are there other Slope types for creating glow effects in SVG?

I have tried to check the docs, but I've come up with a blank.

The part of the code in question is -

<feFuncA  id="SVG_slope-value" type="linear" slope="3"/>

Here's a Codepen to illustrate what I am talking about.

[CodePen ] http://codepen.io/gingerman/pen/WQypBB

There's also a note on there about another issue that I solved for myself.

Thanks

Steve

Solution

Documentation for the component transfer filter is at http://www.w3.org/TR/SVG/filters.html#feComponentTransferElement

The type attribute can have the following values...

type = identity | table | discrete | linear | gamma

When type = linear, you can also have slope and intercept attributes. If c is the initial component then the formula for the remapped component c' is...

c' = slope * c + intercept

In the example you linked to, a Gaussian blur filter is used to create some fuzziness around the object and then a component transfer filter is used to increase the alpha component of the fuzzy area. The end result is a glowing effect. Changing the slope will change the brightness of the glow effect (larger slope results in brighter glow).