Sets the target printer resolution to be used when resizing bitmap images
using magic stretch. (Magic stretch resizes a bitmap for optimal resolution,
based on the target printer resolution and the resolution of the bitmap.
To magic-stretch an image, hold down the Macintosh Command key or the Windows
Ctrl key while resizing.)
Command constructor
PPrinterResol(short nDPI);
Resolution of target printer (from 72 to 32,767 dpi)