8. Printing and exporting images, animations, and data

PAVE provides facilities to print plots, export images and animations, and export subsets of data. In cases where PAVE's built in capabilities do not allow you to capture the images you want (e.g. saving multiple windows together), the tools xv and snapshot may allow you to accomplish your goals.

Printing plots

You probably need to set your PRINTER environment variable prior to launching PAVE for printing to work correctly. (See the Quick PAVE Jump start section for further information.)

To print tile plots, if you are printing to a black and white printer, you should probably choose "Control/Configure" from the plot's menu bar and then experiment with various settings for the colors. You may want to reduce the number of colors in the plot by choosing a smaller number of tiles, or alternatively you may want to choose to use the grayscale colormap. Once you are ready to print the image, just choose the File..Print menu item on the tile plot, and it will be printed on the printer specified by the PRINTER environment variable. If for some reason this doesn't work, then see the sections below on using snapshot and/or xv. These tools will enable you to save a screen captured image to a PostScript file that can then be printed.

To print 3D mesh plots, first decide whether you want to print using black and white or color PostScript. You can then select either the "Black & White PostScript" or the "Color PostScript" button on the 3D mesh plot's "ANIMATING SURFACE" window. Then type in the filename, complete with path name, in the resulting window. Your PostScript will be saved to the chosen file, and then you can issue an lpr command from the Unix command line to print that file.

To print time series line plots or scatter plots, select the "print" button on the plot's window. Then type in the filename, complete with path name, in the resulting window. Your PostScript will be saved to the chosen file, and then you can issue an lpr command from the Unix command line to print that file.

To print time series bar plots, see the sections below on using snapshot and/or xv. These tools will enable you to save an screen captured image to a PostScript file that can then be printed.


Exporting images and animations

Tile plots can be saved as GIF, Postscript, SGI's RGB, XWD, TIFF, and several other image file formats using file menu items on the tile plot.

Tile plots can be saved to an MPEG animation using the File..Save MPEG Animation menu item on the tile plot. Several points to note regarding MPEG animations:

  1. They can take a while to generate.

  2. They use up a fair amount of disk space, typically 0.4MB per frame to generate, and 0.2-0.4 MB for the MPEG file for each 24 hours of animation. This varies proportionally with the size of the image you are animating. It also varies according to the number of changes in the image during animation.

  3. The MPEG animations can be viewed using mpeg_play, which is distributed with PAVE as <pave installation dir> /$EDSS_ENV/bin/OPTIMIZE/public_domain/mpeg_play. Use "mpeg_play -help" for a description of its options. Here is a useful example:

    mpeg_play test.mpeg -loop -framerate 5 -quiet

    "-loop" keeps it looping. "-quiet" keeps it from printing to stdout (which makes the transition from the last frame to the first much faster). "-framerate 5" slows it down to print 5 frames per second.

Tile plots can be saved to an animated GIF using the File..Save Animated GIF menu item on the tile plot. Several points to note regarding animated GIFs:

  1. The animated GIF is created by PAVE using an x window dump
  2. each of the timesteps in the tile plot is then converted to a gif image.
  3. While the animaged GIF is being created by PAVE, the user must not bring up other windows. If other windows cover the tile plot while the x window dumps are being performed, then the animated gif will incorrectly include the contents of these windows rather than the tile plot window.
  4. After the x window dumps are completed, a program called convert creates the animated gif. If there are many timesteps in the dataset, there will be a delay before the user is again given control of the pave gui. After the convert program has finished running, control of the PAVE GUI will return to the user.
  5. The animated GIFs can be viewed using a web browser.

To print other types of PAVE plots, see the sections below on using
snapshot and/or xv. These tools will enable you to save an screen captured image to an image file that can then be printed.


Exporting PAVE data

PAVE's Export menu enables you to save the currently selected formula's data in AVS5 field format, netCDF Models-3 IO/API format, and as tabbed ASCII data suitable for use in spreadsheet applications. (Note that the currently selected formula's data is saved when using the export menu items.) Of particular interest may be the option to export netCDF data. You might find a very large dataset cumbersome to keep around when you are only interested in a small number of variables, perhaps in a small time range or spatial region. PAVE can be used to subselect the variable, time, levels and region of interest and then save this data to a smaller, more manageable dataset. Also, you can save the result of a complex formula to a netCDF file and therefore prevent having to wait for it to compute again.


Using snapshot to create PostScript files from screen images

On an SGI, type snapshot. To view the snapshot menu, place the mouse pointer over snapshot and press the right mouse button. Choose the New file name option to name the file that will be output from snapshot. You should give it a name with a ".rgb" extension. While the mouse pointer is over snapshot, press and hold down the shift key. Then move the mouse pointer to the top left corner of the part of the screen you wish to capture. Then press the left mouse button and drag the mouse pointer until you reach the bottom right corner of the section you want to capture. You should see a red box surrounding the part of the screen that will be captured. If you need to modify the size or location of the box, place the mouse pointer over snapshot and press and hold down the shift button. To move the box, place the mouse pointer inside the box and then drag the box using the middle mouse button. To resize the box, place the mouse pointer near one of the edges of the box and drag the edge (or corner) using the left mouse button.

Once you have selected the portion of the screen to be captured, use the Save as ... option on the snapshot menu to create an RGB file. To convert the RGB file to black and white PostScript, type

tops your_file.rgb > your_file.ps

If you want a color PostScript file, type

tops your_file.rgb -rgb > your_file.ps

You can then use xpsview your_file.ps to view the new PostScript file. You can then capture another image by placing the mouse pointer over snapshot, pressing and holding the shift button, and then creating a new box with your left mouse button.

For more information on snapshot and tops, see their man pages.

Sun also has a version of snapshot that can capture images. The images can be loaded and viewed with imagetool and then saved to a variety of formats, including postscript. Both snapshot and imagetool have nice user interfaces to help you through the process. See the man pages for more information.

Using xv to create PostScript files from screen images

xv is a very usfule tool for capturing and manipulating images - especially GIF files. Type xv to start the program. To view the xv menu, place the mouse pointer over the inital window and press the right mouse button. Click on the grab button with the left mouse button, then use the middle button to drag over the screen region you wish to save to a PostScript file. A copy of these pixels will appear in a separate window.

Now left-click the "xv controls"'s Save button. Choose PostScript from the "Format" menu, and "Full Color" or your preferred color choice from the "Colors" Menu. Next use the browser to save the PostScript to a file. It is recommended that you give the file a .ps extension, to indicate its format.

You can then use xpsview your_file.ps to view the new PostScript file.

xv is available for a variety of UNIX Platforms via anonymous ftp to ftp://www.trilon.com/pub/xv For more information on xv, see the WWW page at http://www.trilon.com/xv

NOTE: xv is a shareware program that you will need to pay $25 to license if you decide to use it. This can be remitted to

    US Mail:  John Bradley
              1053 Floyd Terrace
              Bryn Mawr, PA  19010
    FAX:     (610) 520-2042
Electronic Mail regarding XV should be sent to one of these three addresses:
     xv@trilon.com                        - general XV questions
     xvbiz@trilon.com                     - XV licensing & pricing questions
     xvtech@trilon.com                    - bug reports, technical questions
Next Chapter: Driving PAVE using scripts

Return To Table of Contents