Windows Regions Do Not Scale

• Microsoft Windows Software Development Kit (SDK) for Windows versions 3.1 and 3.0
• Microsoft Win32 Application Programming Interface (API) included with:

      - Microsoft Windows NT versions 3.5 and 3.51
      - Microsoft Windows 95 version 4.0
  

SUMMARY

The coordinates of Windows regions are in device units, not logical units. Therefore, if the mapping mode is not MM_TEXT, region coordinates do not scale as would be expected. This causes particular problems in metafiles because metafiles often use MM_ISOTROPIC or MM_ANISOTROPIC modes to make pictures appear the same on devices with different resolutions.

To work around this problem, applications should avoid using regions if the mapping mode is changed from MM_TEXT. Regions should also be avoided in metafiles, unless the application knows the scaling factor and can adjust region coordinates itself.

MORE INFORMATION

If the applications that will read and write the metafile are developed together, the writing application can include an MFCOMMENT escape in the metafile to store the region components. This information can be used by the reading application to scale the metafile.

However, this comment is not standard across all applications. This method would not be expected to work if the metafile is imported into a commercial application.