Sets the measurement resolutions, which affects the measurements
for certain output formats that does not support physical sizes.
For example, SWF measurements are pixel-based while PDF
measurements are in points (1/72 of an inch). This specifies how
many pixels in SWF an inch in PDF represents.
The values do not affect the pixel sizes of raster-image
contents. If DpiY is omitted, DpiX will set both horizontal and
vertical measurement resolutions. If one of the values (DpiX or
DpiY) is invalid, the other value may be used for both values.
For SWF, these values are used only if XSaveOptions.Template
is an empty string.