How to Draw Cubic Bezier Curves in Windows and Win32s

ID: Q135058

The information in this article applies to:
  • Microsoft Windows Software Development Kit (SDK) 3.1
  • Microsoft Win32 Application Programming Interface (API), used with:
    • Microsoft Windows 95
    • Microsoft Win32s version 1.3
  • Microsoft Windows 2000

SUMMARY

You can get the functionality provided by the Win32 PolyBezier() function on the Windows 3.1 and Win32s platforms. The Bezier sample code shows by example how to draw cubic Bezier curves as well as curves with other degrees on both Windows version 3.1 and Win32s.


MORE INFORMATION

The following file is available for download from the Microsoft Software Library:

BEZIER.EXE
For more information about downloading files from the Microsoft Software Library, please see the following article in the Microsoft Knowledge Base:
Q119591 How to Obtain Microsoft Support Files from Online Services
The PolyBezier() function draws cubic Bezier curves by using the endpoints and control points specified by the lppt parameter. The first curve is drawn from the first point to the fourth point by using the second and third points as control points. Each subsequent curve in the sequence needs exactly three more points: the ending point of the previous curve is used as the starting point, the next two points in the sequence are control points, and the third is the ending point.

Steps to Using the Sample Code

  1. Compile the sample code using the .mak file that corresponds to the platform you are running (Bezier.mak for Win32s and Bezier16.mak for Win16).


  2. Run the compiled program.


  3. Use the left mouse button to position the endpoints and the control points in the client area. As soon as you've positioned enough points to draw a curve with the current degree (the default is cubic so you'll need four points), the curve will be drawn. Keep in mind that if you set the degree to a higher value, you'll have to position degree+1 points before the curve can be calculated and displayed.


Additional query words: Windows Stones GDI kbfile

Keywords : kbfile kbWinOS2000 kbWin32s kbWinOS95 kbSDKWin16
Version : WINDOWS:1.3,3.1,95; winnt:
Platform : WINDOWS winnt
Issue type : kbinfo


Last Reviewed: December 20, 1999
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