6.1.2 Scale Factors
The Scale Factors control contains four boxes that specify horizontal and
vertical scale factors for raster graphics and text output using device
fonts. Unlike all other values specified in the minidriver, the scale
factors are expressed in dots per inch rather than master units. However,
the values specified must still factor evenly into master units.
Text scale factors are used to describe the resolution at which device
fonts were digitized, and graphic scale factors are used to describe the
resolution at which individual pixels are placed upon the page. However,
since graphic scale factors are tracked internally as logarithmic ratios to
text scale factors, graphic scale factors must always either be equal to
the text scale factors or equal to a text scale factor divided by a power
of 2. For example, a text scale factor of 300 dots per inch may use a
graphic scale factor of 300, 150 (300/2), of 75 (300/4), but not a graphic
scale factor of 100.
For most laser printers, text and graphics are sent to the printer in
separate bands. The coordinates of where each object will be placed in a
given band on the page are based upon these scale factors. For example, the
HP LaserJet IIP supports one of several resolutions with an x and y text
scale factor of 300 dots per inch, and a graphics scale factor of 75 dots
per inch. When using this resolution, text printed using device fonts
output will be at 300 dpi accuracy, but raster graphic objects output will
be at 75 dpi accuracy.
For most dot-matrix and ink-jet printers, text and graphics are sent to the
printer in the same band. The coordinates for placement in a given band are
based upon the graphic scale factors. For these printers, the text and
graphic scale factors should always be the same. Attempting to set
different scale factors will not change output quality, and will cause
Windows to not enumerate TrueType fonts when this resolution is selected.
NOTE˙TrueType fonts will not be available for those resolutions where the
text scale factor does not equal the graphic scale factor unless the driver
supports downloading TrueType fonts. For more information about downloading
fonts, see Section 7.6, Specifying Downloadable-Font Commands and Data.
Diconix 150 Plus
For the Diconix 150 Plus minidriver, the text and graphics resolutions are
identical; therefore, the X DPI boxes contain the value 320 and the Y DPI
boxes contain the value 96.
HP LaserJet IIP
For the HP LaserJet IIP minidriver, the device fonts were digitized at the
highest printer resolution (300 dpi); therefore, at the highest graphics
resolution, each Scale Factors box contains the value 300.