Radial Gradients radius

[jeffreyrosenbluth]

We are adding gradients to diagrams and in order to do it properly in the Rasterific backend we need to be able to specify the radius as a proportion between 0 and 1. See for example the SVG definition:

http://www.w3.org/TR/SVG11/pservers.html#RadialGradients

here is an example of SVG code: http://www.w3schools.com/svg/svg_grad_radial.asp

<svg height="150" width="500">
  <defs>
    <radialGradient id="grad1" cx="50%" cy="50%" r="50%" fx="50%" fy="50%">
      <stop offset="0%" style="stop-color:rgb(255,255,255);
      stop-opacity:0" />
      <stop offset="100%" style="stop-color:rgb(0,0,255);stop-opacity:1" />
    </radialGradient>
  </defs>
  <ellipse cx="200" cy="70" rx="85" ry="55" fill="url(#grad1)" />
</svg>

that produces an elliptical gradient.

[Twinside]

The gradient calculation in SVG rely on object bounding boxes, as I don't have any support for bounding boxes, I can't do it quickly.

The main pain point is precise bounding box of cubic & quadratic bezier curve, otherwise it is trivial.

[jeffreyrosenbluth]

It turns out that I was wrong and that I don't think I need % radii. What I need are gradient transforms like Cairo and SVG have. How hard would this be to implement?

[Twinside]

The transformTexture function should fit the bill.

[Twinside]

That being said, I may implement bounding in the future, if I want to make rasterific-svg more or less standard compliant.

[jeffreyrosenbluth]

cool, somehow I missed this :)

On Fri, Apr 18, 2014 at 4:09 AM, Vincent notifications@github.com wrote:

The transformTexturehttp://hackage.haskell.org/package/Rasterific-0.2/docs/Graphics-Rasterific-Texture.html#v:transformTexturefunction should fit the bill.

— Reply to this email directly or view it on GitHubhttps://github.com/Twinside/Rasterific/issues/12#issuecomment-40794109 .