Find the distance from a polygon using the Bourke line-distance algorithm for each segment. Example of it in action here: http://itp.nyu.edu/~gab305/files/gif_with_blurred_borders.gif

distance_from_polygon.cpp

// example of this in action here: http://itp.nyu.edu/~gab305/files/gif_with_blurred_borders.gif

float testApp::distanceFromLine(const ofPoint & p, const ofPoint & l1, const ofPoint & l2){
    float xDelta = l2.x - l1.x;
    float yDelta = l2.y - l1.y;

    //	final double u = ((p3.getX() - p1.getX()) * xDelta + (p3.getY() - p1.getY()) * yDelta) / (xDelta * xDelta + yDelta * yDelta);
    float u = ((p.x - l1.x) * xDelta + (p.y - l1.y)*yDelta) / (xDelta * xDelta + yDelta * yDelta);
    
    ofPoint closestPointOnLine;
    if (u < 0) {
	    closestPointOnLine = l1;
	} else if (u > 1) {
	    closestPointOnLine = l2;
	} else {
        closestPointOnLine = ofPoint(l1.x + u * xDelta, l1.y + u * yDelta);
	}
    
   
    ofPoint d = p - closestPointOnLine;
    return sqrt(d.x * d.x + d.y * d.y); // distance
}


float testApp::distanceFromPoly(const ofPoint & p, const vector<ofPoint> & poly){
    float result = 10000;
    
    // check each line
    for(int i = 0; i < poly.size(); i++){
        int previousIndex = i -1;
        if(previousIndex < 0){
            previousIndex = poly.size() - 1;
        }
        
        ofPoint currentPoint = poly.at(i);
        ofPoint previousPoint = poly.at(previousIndex);
        
        float segmentDistance = distanceFromLine(ofPoint(p.x,p.y), previousPoint, currentPoint);
        
        if(segmentDistance < result){
            result = segmentDistance;
        }
    }
    
    return result;
}

Hi Greg, there's no way you could write this in JavaScript? Or know where I can find a similar module? Kind Regards, Greg