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PostScript

Sabrina can write a PostScript (.ps) file containing the graphics on the screen. There are 2 types of graphics:

• Raster or bitmap graphics is a pixel by pixel copy of what is in the graphics window (or subwindow). Raster images, that are produced with the Dump button on the PostScript Options Dialog or the Post DUMP command, are made by copying the screen and may be requested after an image has been rendered. Raster Dumps made from a color display will automatically give color plots on a color PostScript device and grayscale on a monochrome printer. An image dump will also reproduce any vector graphics, such as particle tracks, that are visible on the screen. Resolution, however, is usually improved by capturing the lines as actual PostScript vector commands.

• Vector graphics include line drawings, particle tracks, text labels, and color legend bars. These are written as PostScript commands as the graphics element is executed if Write PostScript is checked (Post ON command). When printed, vector graphics give higher resolution and a smoother appearance than if the elements were copied as raster graphics. Oblique lines, for example, will not show the jagged appearance caused by the finite bitmap resoution.

Write PostScript

When checked, Sabrina's graphics are written to the current PostScript file. A raster Dump is made automatically following a ray traced Color, Etch, or 2-D Slice picture. Vector graphics operations are written as they are executed.

The Write PostScript mode should be disabled before the file is Printed.

PostScript Options...

Show the PostScript Options Dialog described next.

Write PostScript

Performs the same function as Write PostScript on the File Menu. Apply must be selected for the mode change to take effect.

Compress Bitmaps

When checked, the PostScript raster bitmaps are compressed using run-length encoding. Compessed bitmaps are smaller, sometimes significantly, than uncompressed bitmaps. No data is lost in the compression. The use of compressed bitmaps is highly recommended.

File

The text field shows the name of current PostScript file that is open or will be opened when Write PostScript is enabled. A file name can be tpyed in the field or one chosen in the file selection dialog that is shown by the Browse button.

The file name must be 64 characters or less.

If a file other than the default sabplot.ps (in any directory) is chosen with the file dialog, Sabrina will ask if it is OK to overwrite an existing file.

The file name is restored when Sabrina is restarted without asking if it is OK to overwrite an existing file.

Text

Specify the Size in points and the Font used for text in the PostScript file. The settings apply to both text on the graph (text labels and color legend bars) and the Bottom Labels below the graph. The graphics text is in the same color as on the graph; the Bottom Labels are always black. It is the user's responsibility to ensure that the Font is supported by the target PostScript printer or viewer. The Font need not be the same as the screen font.

Bottom Labels

The Bottom Labels appear below the picture. They are entered in the input window following the Post Label command. A '.' (period) ends the label input. As many label lines can by entered as will fit on the page. The labels can be Centered or Left justified. The distance between the label lines is given by the Line Spacing value.

Vector Graphics Options

Vector graphics can be written in Color, have their color converted to a Gray Scale, or, with the B/W setting, always written as black.

When the Show SubWindows box is checked and the graphics window is divided in subwindows, multiple line drawings will appear on the PostScript page. The maximum number than can appear on a single page is the larger of the number of subwindows in which a drawing is made and the value in the SubWindows per Page box.

The ShowSubWindows setting has a similar effect for ray traced images. When unchecked, each ray traced subwindow is written to a single PostScript page. When checked, the entire graphics window is dumped after each image.

Caution: vector graphics, such as particle tracks, drawn over ray traced images will not be sized correctly when Show SubWindows is checked. The use of the SubWindow mode is discouraged in such situations.

Line Width Multiplier

The value multiplies the line width of PostScript lines. Smaller widths may be desired, for example, when a plot contains lots of particle tracks.

Height Align Factor

The value affects the vertical displacement of graphics text for which a vertical alignment of Top or Center is specified. Top aligned text is moved down by P x F, where P is the Text Size and F is the Height Align Factor. For center aligned text, the displacment is 1/2 of the top aligned displacement.

Dump

Write a Dump of the Graphics Window (or current subwindow if the Show SubWindow setting is checked.) in raster PostScript format. The file will produce color plots on color PostScript printers and will print a greyscale image on monochrome printers. If a Dump is made when the PostScript Mode is OFF, Dump will open the PostScript file (using either the default or the user-specified name), dump the image, and close the file, leaving PostScript in the OFF mode.

PostScript Commands