Extract Geometry from Font

Question

I'd like to be able to extract the geometry for each letter in a TrueType font file. Each letter would have a set of coordinates, assuming each letter is in its own grid.

As a picture tells a thousand words - I'd like to get the vertices for letters similar to the image below (courtesy of http://polymaps.org/ )

Update

Thanks to the hint to use GDI, which is now incorporated into .NET System.Drawing.Drawing2D I got the following code to create WKT polygons. No bezier curves possible. And even after the letters were flipped and rotated some paths still would not join correctly.

        // C# Visual Studio

        GraphicsPath gp = new GraphicsPath();

        Point origin = new Point(0, 0);
        StringFormat format = new StringFormat();
        FontFamily ff = new FontFamily("Arial");
        //enter letter here
        gp.AddString("T", ff, 0, 12, origin, format); //ABCDEFGHIJKLMNOPQRSTUVWXYZ

        StringBuilder sb = new StringBuilder();
        sb.AppendLine("DECLARE @g geometry;");
        sb.Append("SET @g = geometry::STGeomFromText('POLYGON ((");


        Matrix flipmatrix = new Matrix(-1, 0, 0, 1, 0, 0);
        gp.Transform(flipmatrix);
        Matrix rotationtransform = new Matrix();

        RectangleF r = gp.GetBounds();

        // Get center point
        PointF rotationPoint = new PointF(r.Left + (r.Width / 2), r.Top + (r.Height / 2));
        rotationtransform.RotateAt(180, rotationPoint);
        gp.Transform(rotationtransform);
        //gp.CloseAllFigures(); //make sure the polygon is closed - does not work

        foreach (PointF pt in gp.PathData.Points)
        {
            sb.AppendFormat("{0} {1},", pt.X, pt.Y);

        }
        PointF firstpoint = gp.PathData.Points[0];

        sb.AppendFormat("{0} {1}", firstpoint.X, firstpoint.Y); //make last point same as first
        sb.Append("))',0);");
        sb.AppendLine("");
        sb.AppendLine("SELECT @g");
        System.Diagnostics.Debug.WriteLine(sb.ToString());

Answer 1

For Windows, you can use Gdiplus. Create a GraphicsPath and call AddString() on it.

Then examine the PathData or PathPoints.

Answer 2

In Adobe Illustrator

Object Menu > Expand...

This will convert the text to paths made of anchors and Bezier curves.

Aside from using an application, I don't know how to do this programmatically.

Answer 3

I needed the output in MATLAB so took the correctly marked answer using the MATLAB.NET interface. Source code posted below

clear all
% Import .NET Framework System.Drawing
NET.addAssembly('System.Drawing');      

% Display all available System Fonts (optional)
    AvailableFonts = System.Drawing.Text.InstalledFontCollection();
    for i=1:AvailableFonts.Families.Length
        disp(AvailableFonts.Families(i).Name);
    end

% Get GraphicsPath of chosen Font and text string
% https://msdn.microsoft.com/en-us/library/ms142533(v=vs.110).aspx

FontData= System.Drawing.Drawing2D.GraphicsPath();

text='Hello World';
font=System.Drawing.FontFamily('Arial');
style=cast(System.Drawing.FontStyle.Regular,'Int32');
emSize=48;
origin=System.Drawing.Point(0,0);
format=System.Drawing.StringFormat();

FontData.AddString(text,font,style,emSize,origin,format);

%Extract X,Y data from FontData

for i=1:FontData.PathPoints.Length
    x(i)=FontData.PathPoints(i).X;
    y(i)=-FontData.PathPoints(i).Y; 
end

plot(x,y)

Answer 4

也许您可以使用诸如FreeType 2 之类的字体库来解码字体？

Answer 5

Inkscape is free and includes text to path functionality . Some Inkscape functionality is command driven, but I don't know whether that will handle your problem exactly. Inkscape's native format is SVG.