Fun with SetWorldTransform

Wednesday Aug 13th 2003 by William N E Campbell

A version of SetWorldTransform, converted to MFC instead of GDI. SetWorldTransform scales, translates, rotates, shears, and reflects graphics.

Environment: VC6, MFC

This code will show you how useful SetWorldTransform can be. The code will enable you to do things such as:

  • Scale to 1/2 of the original size
  • Translate right by 3/4 inch
  • Rotate 30 degrees counterclockwise
  • Shear along the x-axis with a proportionality constant of 1.0
  • Reflect about a horizontal axis

The code was originally part of the MS SDK, but I have enhanced and converted it to MFC to make it easier to understand.

// The Key part to the source code is using 'SetWorldTransform'
// and setting up the XFORM structure

XFORM xForm;

SetGraphicsMode ( pDC->GetSafeHdc (), GM_ADVANCED );
pDC->SetMapMode ( MM_LOENGLISH );

xForm.eM11 = (FLOAT) 0.5;
xForm.eM12 = (FLOAT) 0.0;
xForm.eM21 = (FLOAT) 0.0;
xForm.eM22 = (FLOAT) 0.5;
xForm.eDx  = (FLOAT) 0.0;
xForm.eDy  = (FLOAT) 0.0;
SetWorldTransform ( pDC->GetSafeHdc (), &xForm );


Download demo project - 8 Kb
Download source - 22 Kb
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