Zero-Width Lines (Strokes); Curved Shapes; Images - Xerox DocuPrint Network Printer Series Guide Manual

POSTSCRIPT

Zero-width lines (strokes)

Curved shapes

Images

2-20
Zero-width lines are lines that have a line width set to zero by the
PostScript master. These lines may not image. The best method is to
specify the sizes of the hairline you want, such as .24 setlinewidth
instead of 0 setlinewidth.
Figure 2-5. Example illustrating fill function
Center
Points of
Pixels
This illustration shows four rows of five pixels on the output device.
The center points of the device pixels are at the cross sections of the
dashed lines. The horizontal lines to be filled are indicated by two
solid, bold line segments per horizontal line.
The horizontal line at the top contains the center points of the second
row of pixels; therefore, the pixels are turned on by the imager. This
is shown by cross hatching the pixels that are turned on. The
horizontal line at the bottom of the picture does not contain the center
points of the fourth row of pixels; therefore, no pixels are turned on,
and the line is not visible.
The flatness parameter is used to set the accuracy with which curves
are rendered on the output device. Because DocuPrint does not use
curve flattening (conversion of curves to line segments) in graphic
rendering, the parameter for the operator setflat has no effect on the
smoothness of curves.
In DocuPrint, the region of the device space to be painted is
determined according to the following rules:
•
Scan Conversion paints only those pixels whose centers lie
within the shape if:
— The resolution of the source image (sampled image) is
higher than the device resolution. Scan Conversion paints
those pixels whose centers lie within the shape.
XEROX DOCUPRINT NPS GUIDE TO USING PAGE DESCRIPTION LANGUAGES
Thickness
of Line