Word wrap a string in multiple lines

Question

I am trying to word wrap a string into multiple lines. Every line will have defined width.

For example I would get this result if I word wrap it to an area of 120 pixels in width.

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Answer 1

For Winforms:

List<string> WrapText(string text, int maxWidthInPixels, Font font)
{
    string[] originalLines = text.Split(new string[] { " " }, StringSplitOptions.None);

    List<string> wrappedLines = new List<string>();

    StringBuilder actualLine = new StringBuilder();
    int actualWidth = 0;

    foreach (var item in originalLines)
    {
        Size szText = TextRenderer.MeasureText(item, font);

        actualLine.Append(item + " ");
        actualWidth += szText.Width;

        if (actualWidth > maxWidthInPixels)
        {
            wrappedLines.Add(actualLine.ToString());
            actualLine.Clear();
            actualWidth = 0;
        }
    }

    if (actualLine.Length > 0)
        wrappedLines.Add(actualLine.ToString());

    return wrappedLines;
}

Answer 2

I'm wanted to wrap text to draw it afterwards in my image. I tried the answer from @as-cii, but it didn't work in my case as expected. It always extends the given width of my line (maybe because I use it in combination with a Graphics object to draw the text in my image). Furthermore his answer (and related ones) just work for >.Net 4 frameworks. In framework .Net 3.5 there is no function Clear() for StringBuilder objects. So here is an edited version:

    public static List<string> WrapText(string text, double pixels, string fontFamily, float emSize)
    {
        string[] originalWords = text.Split(new string[] { " " },
            StringSplitOptions.None);

        List<string> wrappedLines = new List<string>();

        StringBuilder actualLine = new StringBuilder();
        double actualWidth = 0;

        foreach (string word in originalWords)
        {
            string wordWithSpace = word + " ";
            FormattedText formattedWord = new FormattedText(wordWithSpace,
                CultureInfo.CurrentCulture,
                System.Windows.FlowDirection.LeftToRight,
                new Typeface(fontFamily), emSize, System.Windows.Media.Brushes.Black);

            actualLine.Append(wordWithSpace);
            actualWidth += formattedWord.Width;

            if (actualWidth > pixels)
            {
                actualLine.Remove(actualLine.Length - wordWithSpace.Length, wordWithSpace.Length);
                wrappedLines.Add(actualLine.ToString());
                actualLine = new StringBuilder();
                actualLine.Append(wordWithSpace);
                actualWidth = 0;
                actualWidth += formattedWord.Width;
            }
        }

        if (actualLine.Length > 0)
            wrappedLines.Add(actualLine.ToString());

        return wrappedLines;
    }

Because I'm working with a Graphics object I tried @Thorins solution. This worked for me much better, as it wraps my text right. But I made some changes so that you can give the method the required parameters. Also there was a bug: the last line was not added to the list, when the condition of the if-block in the for-loop was not reached. So you have to add this line afterwards. The edited Code looks like:

    public static List<string> WrapTextWithGraphics(Graphics g, string original, int width, Font font)
    {
        List<string> wrappedLines = new List<string>();

        string currentLine = string.Empty;

        for (int i = 0; i < original.Length; i++)
        {
            char currentChar = original[i];
            currentLine += currentChar;
            if (g.MeasureString(currentLine, font).Width > width)
            {
                // exceeded length, back up to last space
                int moveback = 0;
                while (currentChar != ' ')
                {
                    moveback++;
                    i--;
                    currentChar = original[i];
                }
                string lineToAdd = currentLine.Substring(0, currentLine.Length - moveback);
                wrappedLines.Add(lineToAdd);
                currentLine = string.Empty;
            }
        }

        if (currentLine.Length > 0)
            wrappedLines.Add(currentLine);

        return wrappedLines;
    }