Using Angus J Clipper library to outline GraphicsPath text in vb.net

Question

I am creating text in a GDI+ GraphicsPath, using DrawString, and then outputting this to PDF as a path.

This is all working perfectly at the moment.

The time I have an issue is when the chosen font causes the outlines to overlap each other. I have an image example though being a new user i can't upload it... (seems pointless..?..)

I found a library and also someone who has achieved the same as what I am looking for in this blog

I have converted the code snippet to vb.net though I keep getting an empty solution from the library.

Has anybody else managed to pass in a graphicsPath containing a string and retrieve outlined text using this or a similar library?

I managed to get the code from the blog working in the end by using the ClipType.ctUnion instead. Very fast library. I marked the answer below because that code also works; just the one in the blog is simpler and more effective for my needs. — Darren Wainwright, Sep 19 '12 at 18:57

Angus Johnson · Accepted Answer · 2012-09-19T02:04:32.490

Here's some C# code that works ...

    using ClipperLib;

    static public void PathToPolygon(GraphicsPath path, Polygons polys, Single scale)
    {
        GraphicsPathIterator pathIterator = new GraphicsPathIterator(path);
        pathIterator.Rewind();
        polys.Clear();
        PointF[] points = new PointF[pathIterator.Count];
        byte[] types = new byte[pathIterator.Count];
        pathIterator.Enumerate(ref points, ref types);
        int i = 0;
        while (i < pathIterator.Count)
        {
            Polygon pg = new Polygon();
            polys.Add(pg);
            do {

                IntPoint pt = new IntPoint((int)(points[i].X * scale), (int)(points[i].Y * scale));
                    pg.Add(pt);
                i++;
            }
            while (i < pathIterator.Count && types[i] != 0);
        }
    }


    static private PointF[] PolygonToPointFArray(Polygon pg, float scale)
    {
        PointF[] result = new PointF[pg.Count];
        for (int i = 0; i < pg.Count; ++i)
        {
            result[i].X = (float)pg[i].X / scale;
            result[i].Y = (float)pg[i].Y / scale;
        }
        return result;
    }


    private void DrawBitmap()
    {
        Font f = new Font("Arial", 90);
        Pen myPen = new Pen(Color.FromArgb(196, 0xC3, 0xC9, 0xCF), (float)0.6);
        SolidBrush myBrush = new SolidBrush(Color.FromArgb(127, 0xDD, 0xDD, 0xF0));
        path.Reset();
        Polygons polys;
        path.AddString("ABC", f.FontFamily, (int)f.Style, f.Size, new Point(100, 100), null);
        path.Flatten();
        //scale all points up by 100 because Clipper uses integer coordinates
        PathToPolygon(path, polys, 100);
        path.Reset();
        //offset polys remembering to multiply delta by scaling amount ...
        polys = Clipper.OffsetPolygons(polys, 7 * 100, JoinType.jtRound);
        for (int i = 0; i < polys.Count(); i++)
        {
            //reverses scaling ...
            PointF[] pts2 = PolygonToPointFArray(polys[i], 100);
            path.AddPolygon(pts2);
        }
        newgraphic.FillPath(myBrush, path);
        newgraphic.DrawPath(myPen, path);
    }

enter image description here

Thank you Angus. Just trying to convert the code, though having a little touble... any idea how this is done in vb? using Polygon = List; thanks again — Darren Wainwright, Sep 19 '12 at 14:21
No problem, Thanks anyway. I managed to convert the code, though also got the code in my Q working too - had to use ClipType.ctUnion. It works so fast! You've made a great library there :) — Darren Wainwright, Sep 19 '12 at 18:56
Yes, I misread outline as offset so, of course, 'unioning' the polygons is exactly what you would need to do. Anyhow, thanks for your encouraging feedback re my Clipper library. — Angus Johnson, Sep 20 '12 at 05:11

Using Angus J Clipper library to outline GraphicsPath text in vb.net

1 Answers1