Re: Method for finding intersection points

Hi, All

> I strongly agree.
+1

Such functions are primitive and important functions of the geosptial information systems (GIS). I expect such an evolution of SVG, though I do not hope that all of them are implemented immediately. It will facilitate that we can treat SVG content as data for GIS and web browser as GIS framework.

Various topological operations;
 http://tsusiatsoftware.net/jts/jts-features.html
Javascript implementations of them;
 http://lin-ear-th-inking.blogspot.jp/2011/05/jts-arrives-in-javascript.html

Regards,

Satoru Takagi

> Hi, Nikita-
> 
> I strongly agree.
> 
> In writing apps with SVG and JS, I've wanted to have an easy way to get 
> intersections for many different things. I'm currently using Kevin 
> Lindsey's intersection library on a personal project.
> 
> I actually believe that we should work on a more comprehensive API for 
> point, vector, and matrix math (including intersections), which could be 
> used for both SVG and Canvas (and possibly CSS); JS libs like Sylvester 
> [1] and mjs [2] are a good start, but would have better performance if 
> implemented natively in browsers. I don't have the math skills to do 
> this myself, but if we could find someone to help spec it out, I could 
> facilitate the spec production.
> 
> [1] http://sylvester.jcoglan.com/
> [2] http://webgl-mjs.googlecode.com/hg/docs/files/mjs-js.html
> 
> Regards-
> -Doug
> 
> On 6/19/13 6:27 AM, Nikita Vasilyev wrote:
> > I propose to implement a method for finding intersection points for
> > basic shapes and paths.
> >
> > svgElements.getIntersectionPoints( svgElement )
> > -> Array of points, e.g. [{x: 1, y: 120}, …]
> >
> > There are JavaScript libraries for this
> > http://www.kevlindev.com/geometry/2D/intersections/
> > http://raphaeljs.com/reference.html#Raphael.pathIntersection
> >
> > There is a getIntersectionList method which calculates intersection
> > using bounding boxes of the elements
> > (http://dev.w3.org/SVG/profiles/1.1F2/publish/struct.html#__svg__SVGSVGElement__getIntersectionList)
> > It does NOT return intersection points.
> >
> > Motivation
> > Finding intersection is commonly used for drawing and prototyping
> > applications such as Adobe Illustrator to "snap" objects.
> 
> 
>

Received on Thursday, 20 June 2013 07:58:10 UTC