rasterizer routine (C#)

void _RasterizeSortedEdges(float tx, float ty, float scale, SvgRasterizerCachedPaint cache, SvgFillRule fillRule)
{
    SvgRasterizerActiveEdge active = null;
    int y, s;
    int e = 0;
    int maxWeight = (255 / SVG_SUBSAMPLES);  // weight per vertical scanline
    int xmin, xmax;

    for (y = 0; y < height; y++)
    {
        Array.Clear(scanline, 0, width);
        xmin = width;
        xmax = 0;
        for (s = 0; s < SVG_SUBSAMPLES; ++s)
        {
            // find center of pixel for this scanline
            float scany = (float)(y * SVG_SUBSAMPLES + s) + 0.5f;
            SvgRasterizerActiveEdge step = active;

            // update all active edges;
            // remove all active edges that terminate before the center of this scanline
            while (step!=null)
            {
                SvgRasterizerActiveEdge z = step;
                if (z.ey <= scany)
                {
                    step = z.next;  // delete from list
                                        //                  NSVG__assert(z->valid);
                    _FreeActive(z);
                }
                else
                {
                    z.x += z.dx;            // advance to position for current scanline
                    step = step.next;  // advance through list
                }
            }

            // resort the list if needed
            for (; ; )
            {
                bool changed = false;
                step = active;
                while (step!=null && step.next!=null)
                {
                    if (step.x > step.next.x)
                    {
                        SvgRasterizerActiveEdge te = step;
                        SvgRasterizerActiveEdge q = te.next;
                        te.next = q.next;
                        q.next = te;
                        step = q;
                        changed = true;
                    }
                    step = step.next;
                }
                if (!changed) break;
            }

            // insert all edges that start before the center of this scanline -- omit ones that also end on this scanline
            while (e < edges.Count && edges[e].y0 <= scany)
            {
                if (edges[e].y1 > scany)
                {
                    SvgRasterizerEdge edge = edges[e];
                    SvgRasterizerActiveEdge z = _AddActive(ref edge, scany);
                    edges[e] = edge;
                    if (z == null) break;
                    // find insertion point
                    if (active == null)
                    {
                        active = z;
                    }
                    else if (z.x < active.x)
                    {
                        // insert at front
                        z.next = active;
                        active = z;
                    }
                    else
                    {
                        // find thing to insert AFTER
                        SvgRasterizerActiveEdge p = active;
                        while (p.next!=null && p.next.x < z.x)
                            p = p.next;
                        // at this point, p->next->x is NOT < z->x
                        z.next = p.next;
                        p.next = z;
                    }
                }
                ++e;
            }

            // now process all active edges in non-zero fashion
            if (active != null)
                _FillActiveEdges(scanline, width, active, maxWeight, ref xmin, ref xmax, fillRule);
        }
        // Blit
        if (xmin < 0) xmin = 0;
        if (xmax > width - 1) xmax = width - 1;
        if (xmin <= xmax)
        {
            _ScanlineSolid(null,0, readCallback, writeCallback, xmax - xmin + 1, scanline,xmin, xmin, y, tx, ty, scale, cache);
        }
    }
}