Search
Module:
Directory

   Desktop Functions:

   Smart Device Functions:


Show Recent Changes
Subscribe (RSS)
Misc. Pages
Comments
FAQ
Helpful Tools
Playground
Suggested Reading
Website TODO List
Download Visual Studio Add-In

TextOut (gdi32)
 
.
Summary

C# Signature:

[DllImport("gdi32.dll", CharSet = CharSet.Auto)]
static extern bool TextOut(IntPtr hdc, int nXStart, int nYStart,
   string lpString, int cbString); (Please see note for CharSet in tips)

VB.NET Signature:

    <DllImport("gdi32")> _
    Shared Function TextOut(ByVal hdc As IntPtr, ByVal x As Integer, _
      ByVal y As Integer, ByVal textstring As String, _
      ByVal charCount As Integer) As Boolean
    End Function

Notes (From Author/Editor Gabriel Sharp)

If you use TextOut, you will need to save the screen to a back buffer or else this output will disappear. You can either use a backbuffer directly or through the Graphics.CopyFromScreen method. Advanced users might also try the BitBlt Api call, which can sometimes, under certain conditions, be faster.

Tips & Tricks:

This API is useful for TextOut preparation or post comparison. These API's are most useful when working with fonts other than

(but not restricted to) True Type, Open Type, and PostScript fonts. The most common being raster (pixel) fonts which are not supported

by the .NET framework. TextOut and it's helpers tend to be a bit faster because they are unmanaged and work well with .NET's existing

[Graphics.GetHdc()] method. Any graphics / bitmap pair you create will already have a default font, and you can start using TextOut and the above function right away without having to pre-init all the stuff that goes with it (Fonts, Brushes, etc). Good luck!

[CharSet = CharSet.Auto] According to my experience, this parameter should be used (if you use it also when defining the LOGFONT structure and CreateFontIndirect fuction), otherwise the selected font will not be displayed. All flags will be done (lfItalic, lfUnderline ...) but not the lfFaceName string.

Sample Code:

    // Paste this at the beginning of your file if not present:

using System.Drawing;

using System.Runtime.InteropServices;

    // Paste This Inside a New Form's Code After InitializeComponent() {}

    [DllImport("gdi32.dll")]
    static extern bool TextOut(IntPtr hdc, int nXStart, int nYStart,
       string lpString, int cbString);
    [DllImport("gdi32.dll")]
    static extern bool GetTextExtentPoint(IntPtr hdc, string lpString,
       int cbString, ref Size lpSize);

    int x = 0;
    int y = 0;

    protected override void OnKeyPress(KeyPressEventArgs e)
    {
        IntPtr HDC = CreateGraphics().GetHdc();
        Size MeasureSize = new Size(0, 0);
        String strOut =  e.KeyChar.ToString();
        int strLen =  e.KeyChar.ToString().Length;

       TextOut(HDC, x,y, strOut,strLen);

        GetTextExtentPoint(HDC, strOut, strLen, ref MeasureSize);

        x += MeasureSize.Width;

        if ((x+MeasureSize.Width) > ClientRectangle.Width)
        {
        y += MeasureSize.Height;
        x = 0;
        }

    }

Alternative Managed API:

Graphics.DrawString
Graphics.MeasureString
Graphics.MeasureCharacterRanges

Documentation
TextOut on MSDN

Please edit this page!

Do you have...

  • helpful tips or sample code to share for using this API in managed code?
  • corrections to the existing content?
  • variations of the signature you want to share?
  • additional languages you want to include?

Select "Edit This Page" on the right hand toolbar and edit it! Or add new pages containing supporting types needed for this API (structures, delegates, and more).

 
Access PInvoke.net directly from VS:
Terms of Use
Find References
Show Printable Version
Revisions