@node Programs, Problems, Functions, Top
@chapter Programs
@cindex programs
This chapter of the manual describes the use of some of the programs
which use the GIMP-Print library (libgimpprint). Note that there is now
a user manual in DocBook/SGML format, currently provided in HTML,
PostScript and PDF formats which is distributed with GIMP-Print. This
manual currently covers the use of the GIMP Print plugin and CUPS
drivers.
@menu
* The GIMP plugin:: The print plugin for the GIMP
* Ghostscript:: Printer driver
* CUPS:: Printer driver
@end menu
@node The GIMP plugin, Ghostscript, Programs, Programs
@section The GIMP Print plugin
@cindex GIMP Print plugin
@cindex Print plugin
The GIMP Print plugin is the printing facility for the GNU Image
Manipulation Program@footnote{@uref{http://www.gimp.org}}. This section
examines the features offered by the Print plugin.
The main window is divided into five panes:
@subsection Preview
The Preview pane contains a positioning widget that allows interactively
positioning the output on the page. It contains an outer border,
representing the sheet of paper; an inner border, representing the
printable area of the printer; an arrow, pointing to the top of the page
(the end that's fed into the printer); and a black rectangle,
representing the position of the image on the page. The image can be
moved around on the paper. When the first (left) button is used, the
image is moved in screen pixels; when any other button is used, the
image is moved in points@footnote{The output resolution of the plugin.}.
The arrow resizes depending upon the media size chosen; the shaft of the
arrow is always equal to one inch on the output.
@image{print-main,,4in}
@subsection Printer Settings
The Printer Settings pane contains a dropdown menu for selecting a
printer to print to. There is a special `printer' named @samp{File}
that allows you to choose a file to print to, rather than a printer
queue. The Setup box to the right allows specification of a printer
type, a PPD file@footnote{For Postscript printers.}, and the command to
be used to print. Each distinct printer in the Printer list can have
different settings applied to it. Below that is a combo box allowing
choice of media size. The choices are constrained to those that the
printer supports. Below that are dropdown menus for choosing media type
(what kind of paper), media source (what input tray), ink type, and
resolution. All of these settings are printer-specific.
@image{print-setup,,2in}
@subsection Position
The Position pane contains various widgets to place the image on the
paper. These widgets work in conjunction with the Preview pane. At the
top of the pane is a button to center the image on the paper (not on the
printable area), and on either side buttons to center vertically and
horizontally. Below these are four boxes that allow entry of the left,
top, right, and bottom of the image. These positions are relative to
the top left of the paper@footnote{Again, that's relative to the paper
corner, not the printable area, which is usually smaller.}. There are
two additional boxes that allow specification of the right margin and
bottom margin if you prefer; these are relative to the bottom right
corner of the paper. Any of these may have values entered into them;
the preview image will be moved appropriately.
@strong{Note}: These entries do not resize the image.
Finally, there is a pick box for orientation (landscape or portrait).
There is an @samp{Auto} mode that picks the orientation that yields the
orientation that best matches that of the image to be printed.
@subsection Scaling
The Scaling pane contains a slider that allows scaling of the image.
The image can be scaled in either percent of the printable area
(@strong{not} the page in this case) or pixels per inch (PPI) via a
radio button below the slider. PPI allows matching image resolution to
printer resolution. The image may be scaled using either method to
between 5 and 100% of the imageable area. It is not possible to crop
with the Print plugin. In Percent mode, the image is scaled so that
neither axis will be longer than the percent of the printable area
specified. For example, if you print an image at 20%, it will be
possible to tile the image 5 times on one axis and at least 5 times on
the other. To the right of the radio button is a button called Set
Image Scale. This sets the scaling to PPI, and sets the resolution as
closely as possible to the resolution stored in the image. To the right
of the Set Image Scale button are two boxes that allow entry of width
and height of the image. These set the scaling mode to PPI. Specifying
one automatically sets the other, and the image is repositioned as
needed to prevent it from falling off the edge of the page.
To its right is a button group that allows choosing English (inch)
units or metric (centimeter) units.
@subsection Image Settings
The Image Settings pane allows choice of Line Art, Solid Colors, or
Photograph image type. Line art or Solid Colors should be used for
graphics containing mostly solid areas of color. They're very similar
to each other. Photograph mode dithers more slowly, but produces more
accurate colors. To the right of these three radio buttons is a button
called Adjust Color. This pops up a new window that controls various
output quality settings. That will be described separately. Finally,
there is a choice of Black and White, Color and Monochrome output.
Monochrome output can be used to print absolute black and white very
quickly.
@subsubsection Adjust Output
The Adjust Output button button pops up a non-modal dialog that allows
adjustment of various parameters related to the print quality. These
are independent of the controls within the GIMP itself and only affect
the print.
@image{print-color,,2in}
At the top of the window is a thumbnail of the image that changes to
reflect the color settings of the image. This enables you to get an
idea of how the image will print out as you adjust settings.
Below that there are eight sliders:
@table @emph
@item Brightness
(0--2.0, default 1.0) Adjust the brightness of the image.
@item Contrast
(0--4.0, default 1.0) Adjust the output contrast.
@item Cyan, Magenta, Yellow
(0--4.0, default 1.0) Adjust the cyan, magenta, and yellow in the
output. These should not normally need to be adjusted very much; even
very small adjustments can go quite a long way to restoring color
balance.
@item Saturation
(0--9.0, default 1.0) Adjust the color brilliance (saturation) of the
output. Saturation of 0 means pure gray scale, with no color.
Saturation of 9.0 will make just about anything but pure grays
brilliantly colored.
@item Density
(0.1--2.0, default 1.0) Adjust the density (amount of ink) in the print.
The density is automatically corrected for the particular printer,
resolution, and in some cases paper choices. If solid black in the
input is not solid in the print, the density needs to be increased; if
there is excessive ink bleed-through and muddy dark colors, the density
should be decreased.
@strong{Note}: the density will not increase beyond a certain amount no
matter what the slider is set to.
@item Gamma
(0.1--4.0, default 1.0) Adjust the output gamma. The gamma value is
automatically corrected for the choice of printer; this is used if you
believe the automatic setting is incorrect.
@end table
@subsubsection Dither Algorithm
There is also a selection box for the dither algorithm to be used in the
pop-up dialog. There are currently seven choices:
@table @emph
@item Adaptive Hybrid
Adaptive Hybrid usually yields the best output quality; it chooses a
modified Floyd-Steinberg error diffusion algorithm or ordered dithering
depending upon the image characteristics.
@item Ordered
Ordered uses a pure ordered dither. It generally yields excellent
quality for simple black and white or four color printers without
variable drop size or drop modulation; it is not recommended if high
quality is desired on six color printers. It is considerably faster
than Adaptive Hybrid.
@item Fast
Fast also uses a pure ordered dither, but uses a very simple black model
and makes no attempt to handle multi-level (6-color, variable drop size,
or drop modulation) at all cleanly. It is substantially faster than
Ordered dither. The quality tends to be quite poor except on simple
four color printers. On three color printers, quality is probably
competitive with anything else.
@item Very Fast
Very Fast is similar to Fast, except that it uses a very simple dither
matrix that can be looked up much more quickly than the matrix used in
the Fast dither. For simple pure black and white images dominated by
horizontal and vertical lines, this may actually yield the best results;
for other types of image, the quality will be poor.
@item Adaptive Random
Adaptive Random is similar to Adaptive Hybrid, except that the
modifications to the Floyd-Steinberg algorithm are slightly different.
This is slower than Adaptive Hybrid on most systems. For some images
the quality may be better than Adaptive Hybrid, but generally Adaptive
Hybrid should yield slightly superior images.
@item Hybrid Floyd-Steinberg
Hybrid Floyd-Steinberg uses the modified Floyd-Steinberg algorithm of
Adaptive Hybrid on the entire image. Generally, the results are poor in
pale regions.
@item Random Floyd-Steinberg
Random Floyd-Steinberg uses the modified Floyd-Steinberg algorithm of
Adaptive Random on the entire image. Generally, the results are poor in
pale regions.
@end table
@subsection Action Buttons
The last pane contains four action buttons:
@table @emph
@item Print and Save Settings
Immediately print the image (or, if the File printer is chosen, display
a file selection window to pick the output file), and save all current
settings for all printers.
@item Save Settings
Immediately save the settings, and continue working in the Print plugin.
@item Print
Immediately print the image (or, if the @samp{File} printer is chosen,
display a file selection window to pick the output file), but do not
save settings.
@item Cancel
Immediately quit without saving settings or printing.
@end table
@node Ghostscript, CUPS, The GIMP plugin, Programs
@section Ghostscript driver
@cindex ghostscript driver
@node CUPS, , Ghostscript, Programs
@section CUPS driver
@cindex CUPS driver