Graph drawing algorithm

Question

I have an undirected graph on matris by vertex adjacency relations like that;

    /*    a  b  c  d
     * a -1  0  1  1
     * b  0 -1  1  1
     * c  1  1 -1  1
     * d  1  1  1 -1 
     *
     */

    int G[4][4] = {{-1, 0, 1, 1},
                   { 0,-1, 1, 1},
                   { 1, 1,-1, 1},
                   { 1, 1, 1,-1}};

I want to draw this graph on cordinate system. What's the algorithm that gives each vertex position (x,y) by any method(force-directed, spring vs)? I just ask the pseudocode, not any library or software to draw. Thanks.

Answer 1

Here is the well-decribed algorithm with as3. I solved the my problem. Thanks. http://blog.ivank.net/force-based-graph-drawing-in-as3.html

Answer 2

Here's a circle graph layout modified from the prefuse library:

void layoutPoints(int rows, int cols, Point **coordinates, Rectangle maxSize)
{
    int nn = rows * cols;
    int width = maxSize.width;
    int height = maxSize.height;
    int centerX = maxSize.x + (width / 2);
    int centerX = maxSize.y + (width / 2);

    int radius = 0.45 * (height < width ? height : width);

    for (int i = 0; i < width; i++)
    {
        for (int j = 0; j < width; j++)
        {
             double angle = (2 * M_PI * i) / nn;
             double x = cos(angle) * radius + centerX;
             double y = sin(angle) * radius + centerY;
             coordinates[i][j].x = round(x);
             coordinates[i][j].y = round(y);
        }
    }
}

You could change this to use floats or doubles if you needed to as well.