How to measure the pixel width of a digit in a given font / size (C#)

Question

I am trying to calculate the pixel width of Excel columns, as described in this post, using the official formula from the OpenXML specification. However, in order to apply t

Answer 1

MeasureText adds padding, the amount is fairly unpredictable although it roughly scales linearly with the font size. The trick is to subtract two measurements to get rid of the padding. This code generated very happy numbers:

        float size = 5;
        for (int ix = 0; ix < 10; ++ix) {
            var font = new Font("Calibri", size, FontStyle.Regular);
            string txt = new string('0', 100);
            SizeF sz1 = TextRenderer.MeasureText("00", font) - TextRenderer.MeasureText("0", font);
            Console.WriteLine("{0} {1:N3}", size, sz1.Width);
            size += 2;
        }

Output:

5 4.000
7 5.000
9 6.000
11 7.000
13 9.000
15 10.000
17 12.000
19 13.000
21 14.000
23 16.000

That gets you the 7 pixels you're looking for. Beware that you'll have to accommodate TrueType hinting, it can adjust the shape of the digit so that its main stems fall on pixel boundaries. Add at least one pixel.