How can i determine the width of a drawn string?

Question

I'm drawing a string using the following:

g.DrawString(somestring, somefont, new SolidBrush(Color.Black), X where it starts, Y where it starts));

Problem:

Sometimes I want to align the drawn string on the left side of a line. But, it doesn't work if I don't know what the string length will be.

Possible but noob solution:

Count the number of chars, multiply for a trial and error value, and subtract it on X position, like this:

string somestring = Convert.ToString(Math.Round(10 * somevalue) / 10) + "m";
int stringcount1 = somestring.Count();
g.DrawString(somestring, somefont, new SolidBrush(Color.Black), X -stringcount1 * trialanderrorvalue, Y));

This doesn't work because, as you can guess, I'm creating a number, and that number can have a decimal separator or not.

And that is the problem, because the decimal separator is not a very wide character, but still counts, it will be sending my string neptune-far from the line. Or I can get a decent trial and error value for a number with a decimal separator, and if eventually the number doesn't have a decimal separator it will be above the line (and ruin the drawing).

Any hints? Possibly forcing the string to have a ,0 in the case that the number is a integer?

Edit:

I've now created a method that will return aSizeF object given a string and a font.

    static SizeF MeasureStringMin(string measureString, Font stringFont, PaintEventArgs e)
    {
        //// Set up string. 
        //string measureString = "Measure String";
        //Font stringFont = new Font("Arial", 16);

        // Measure string.
        SizeF stringSize = new SizeF();

        stringSize = e.Graphics.MeasureString(measureString, stringFont);

        return stringSize;
    }

The problem is that when I recall this function using something like

SizeF stringSize = new SizeF();
stringSize = MeasureStringMin(somestring, somefont, ????)

I never know what to put in the third variable, hints on this? Why do I need the PaintEventArgs?

Which exact library are you using? WPF, XNA, GDI? Or more specifically, what's the type of the `g` variable? — Mephy, Apr 26 '15 at 00:56
Always assume that that operator exists and if not add .00 ? — joachim, Apr 26 '15 at 00:56
@JoachimGotzes, yes that's a possibility, but a complex one, also, could easily get messy — ng80092b, Apr 26 '15 at 01:27

Blorgbeard · Accepted Answer · 2015-04-26T01:05:39.527

2

You need the MeasureString function! Use it to get the exact dimensions of the string before you draw it, and adjust the position accordingly.

edited Apr 26 '15 at 01:05

answered Apr 26 '15 at 00:57

Blorgbeard

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I've updated the question, and there's a simple issue I'm sure you can easily clear out, can you take a look? – ng80092b Apr 26 '15 at 01:43
You need the PaintEventArgs (`e`), because you're calling `e.Graphics.MeasureString`. You need a `Graphics` instance to call MeasureString on. You should be doing this in the `Paint` event handler, so you should have an `e` to pass along. – Blorgbeard Apr 26 '15 at 04:00
1

If you don't have a `PaintEventArgs` (because you're drawing on a bitmap or something), then you will still have a `Graphics` instance that you're drawing with, so just use that instead of `e.Graphics`. You might wish to change your method's signature to accept a `Graphics` object rather than a `PaintEventArgs`. That method is just a simple pass-through to MeasureString anyway though, so I would say you don't need it, really... – Blorgbeard Apr 26 '15 at 04:03

How can i determine the width of a drawn string?

1 Answers1