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Vis > image_printing > Image Programs
Image Programs
BIT
DESCRIPTION
- BIT is a very comprehensive image editor based on SGI's GL graphics library.
PLUSES
- Large variety of tools.
MINUSES
- Non-standard GL interface.
HOW TO INVOKE
- To start BIT by itself just enter:
- bit
- or with an image:
- bit test.rgb
HINTS
DOCUMENTATION
- man page
- Built-in help menus
CLRpaint
DESCRIPTION
- CLRpaint is a full-screen 24-bit paint program.
PLUSES
- Very fast display since it's based on GL (hardware accelerated).
MINUSES
- Always full-screen so it's not possible to switch to other applications while running CLRpaint.
- Saves full-screen unless a smaller rectangle is drag-selected.
- Non-standard GL interface.
HOW TO INVOKE
- clrpaint
HINTS
DOCUMENTATION
- Official CLRpaint WWW page
Compression Viewer
DESCRIPTION
- Compression Viewer allows you to see how different levels of JPEG compression affect the quality and size of an image. It displays the original image size (raw data of 4 bytes/pixel) versus the JPEG compressed size and the compression ratio.
PLUSES
- Easy to use.
- Very fast display since it's based on GL (hardware accelerated).
- Built-in zoom window.
- Window showing the differences between the images (mean square error).
MINUSES
- Limited save capabilities.
HOW TO INVOKE
- To start the Compression Viewer in IRIX just enter:
- compview
- or with an image:
- compview test.rgb
HINTS
DOCUMENTATION
Desi
DESCRIPTION
- Desi is a convenient program for compositing images and text onto a background. Showcase could have been used for this purpose, but it cannot export images. PowerPoint is recommended as an alternative since this is no longer supported.
PLUSES
MINUSES
HOW TO INVOKE
- desi (not available)
HINTS
DOCUMENTATION
- man page
- Official Desi no longer supported.
Ghostview
DESCRIPTION
- Ghostview is a basic PostScript viewer that is a front-end to the Ghostscript interpreter. It was developed years ago for multiple Unix systems and its age is obvious from the simple interface utilizing old-style X widgets. Despite the interface being somewhat dated, Ghostview is a fairly powerful program. It can cope with many types of PostScript files even those that do not strictly comply with the official Adobe PostScript standard. Ghostview provides controls over page selection, orientation, simple magnification, and has the ability to mark individual pages and save or print them rather than dealing with the entire document.
PLUSES
- Easy to use.
- Sometimes displays PostScript text more accurately than Xpsview.
- Works nicely with FrameMaker, unlike Xpsview which sometimes fails when both programs try to run simultaneously.
- Marking and saving/printing individual pages out of a larger document.
MINUSES
- Old-fashioned X interface.
- Limited zoom capability.
- No antialiasing, so small text can be difficult to read.
- Cannot create it's own private colormap.
HOW TO INVOKE
- ghostview file.ps
HINTS
- Try MGv or Gv instead for a better interface and additional features.
- Try Xpsview if a PostScript file should fail to display with Ghostview, Gv, or MGv.
DOCUMENTATION
Gv
DESCRIPTION
- Gv is a PostScript viewer that is a front-end to the Ghostscript interpreter. It is based on the older Ghostview and has a number of significant enhancements. It can cope with many types of PostScript files even those that do not strictly comply with the official Adobe PostScript standard. Like Ghostview, Gv provides controls over page selection, orientation, magnification, and has the ability to mark individual pages and save or print them rather than dealing with the entire document. Gv also provides antialiasing and a more intuitive zoom capability like MGv.
PLUSES
- Slick and intuitive interface.
- Sometimes displays PostScript text more accurately than Xpsview.
- Works nicely with FrameMaker, unlike Xpsview which sometimes fails when both programs try to run simultaneously.
- Marking and saving/printing individual pages out of a larger document.
- Antialiasing which greatly improves the readability of text!
- Intuitive multi-level page zooming.
- Reads compressed files!
- Pan around a page larger than the window by holding down the left mouse button and dragging.
- May display some files (particularly those out of WordPerfect) which fail with Ghostview, MGv, or Xpsview.
MINUSES
- Cannot create it's own private colormap.
HOW TO INVOKE
- To start Gv with antialiasing off by default:
- gv file.ps
- or with antialiasing initially on:
- gv -antialias file.ps
HINTS
- Try MGv instead for its private colormap capability.
- Try Xpsview if a PostScript file should fail to display with Gv, Ghostview, or MGv.
DOCUMENTATION
- Official Gv WWW page and on-line manual
Icop (deprecated)
DESCRIPTION
-
Icop is a program for analyzing and correcting images for
display on NTSC (or PAL) video. Computer systems can display a far
greater range of colors than will fit into the video bandwidth. When
transferring an image to video, colors outside of the "legal" range will
have their values clipped. This may result in an undesirable looking
picture displaying problems such as color bleeding.
Icop addresses these differences in the color spaces by reducing the luminance and saturation of an image so that all its pixels fall within the legal range for NTSC (or PAL) video. The example image above shows Icop in action. It can display the original image, all the legal pixels, all the illegal pixels, and the corrected version which can subsequently be saved. The graph in the Icop window shows a plot of luminance (vertical) versus saturation (horizontal) for all the pixel values in the image. The dark, triangular region on the left-side contains the legal values for video (NTSC in this case). Values below this region are over saturated and values below are undersaturated.
PLUSES
- Easy to use.
- Fast and visual way to tell if (and where) an image is not video-friendly.
MINUSES
- Cannot run in batch mode (see rgblegal below).
HOW TO INVOKE
- icop
HINTS
- It's not absolutely necessary to rework an image so as to eliminate ALL the offending colors/pixels - experience has shown that slight transgressions aren't that consequential.
DOCUMENTATION
- man page
- Official Icop page no longer supported
ImageMagick
DESCRIPTION
-
ImageMagick is not a single program, but rather a collection
of programs that perform a large variety of image processing functions.
The tools in the package consist of the following:
- animate - directly animates a sequence of images on the screen
- combine - combine a series of images to create new images
- convert - converts an image from one format to another with optional image processing
- display - an interactive (GUI) image processor and viewer
- identify - describes the format and characteristics of image files
- import - saves any window or portion of the screen to an image file
- mogrify - transforms a sequence of images with processing operations
- montage - creates a composite image from a group of images
PLUSES
- display can view images larger than the screen by providing panning capability.
HOW TO INVOKE
- convert inputimage.rgb outputimage.gif
- display imagename
HINTS
- The format used for saving images is usually dependent on the file name's extension. A ".sgi" extension specifies the SGI RGB format, ".gif" is GIF89a, ".gif87" is GIF87a, etc.
DOCUMENTATION
- Official ImageMagick WWW page
Image Works
DESCRIPTION
- Image Works is a fairly good image processing program that's part of SGI's ImageVision tool set. It provides transformation tools for cropping, adding a border, scaling, stretching, flipping, and rotating. There are color enhancement tools for blurring, sharpening, adjusting the brightness, contrast, color balance, color saturation and equalization. There are several tools for effects such as image negation, conversion to grayscale, thresholding, color reduction, and edge detection. Finally, miscellaneous capabilities include a color histogram, adjustable zoom, and multiple levels of undo.
PLUSES
- Easy to use.
MINUSES
- Limited save formats.
- Only uses compression when saving images in TIFF format, not in the SGI RGB format.
- Always saves an image with 4 bytes per pixel even if the input image only has 3 bytes per pixel.
HOW TO INVOKE
- To start Image Works, select it from the "Image Tools" menu in the toolchest
- or just enter:
- imgworks
- or with an image:
- imgworks test.rgb
HINTS
- Since Image Works doesn't use any compression for SGI RGB images, they tend to get rather large. Therefore, it's a good idea to resave them with another program (such as rle) that always uses compression.
- Image Works is especially useful for cropping out parts of an image. The cropping tool is very flexible in that you can type in specific numbers for cropping amounts as well as adjusting the bounding rectangle with the mouse. You can always undo if the results are not satisfactory.
DOCUMENTATION
- man page
- On-line manuals in the IRIS InSight Library
ImgSnap
DESCRIPTION
- ImgSnap is part of SGI's ImageVision tool set and is used for saving rectangular areas anywhere on the screen as images. In order to save a portion of the screen, just click on "Selected Area" then use "Grab Selection Focus" to drag out a rectangle with the left mouse button over the desired area. If the rectangle is very large and ImgSnap's window blocks some of it, then click on "Vanish While Saving" so that the window temporarily disappears during the saving. This might be necessary since ImgSnap saves exactly what you see on the screen regardless of the window stacking order.
PLUSES
- Easy to use.
MINUSES
- Limited save formats.
- Doesn't use any compression when saving images.
HOW TO INVOKE
- To start ImgSnap, select it from the "Image Tools" menu in the toolchest
- or just enter:
- imgsnap (no longer supported)
HINTS
- Since ImgSnap doesn't use any compression when saving images, they tend to get rather large. Therefore, it's a good idea to resave them with another program (such as rle) that always uses compression.
DOCUMENTATION
- man page (no longer supported)
ImgView
DESCRIPTION
- ImgView is part of SGI's ImageVision tool set and is used to quickly view one or more images (SGI RGB, GIF, JPEG, TIFF, and PhotoCD formats).
PLUSES
- Easy to use.
- Very fast display since it's based on GL (hardware accelerated).
- Ability to simultaneously view and manipulate multiple images in the same window.
- Built-in zoom window.
MINUSES
- Limited save formats.
- Doesn't use any compression when saving images in SGI RGB and TIFF formats.
- No quality setting option when saving images in JPEG format.
HOW TO INVOKE
- To start ImgView in IRIX by itself just enter:
- imgview
- or with an image(s):
- imgview test1.rgb test2.rgb ...
HINTS
- ImgView's multi-image capability is especially useful for quickly compositing several images and then saving the result with the "save full window" option.
- Since ImgView doesn't use any compression for SGI RGB and TIFF images, they tend to get rather large. Therefore, it's a good idea to resave them with another program (such as rle) that always uses compression.
DOCUMENTATION
- man page
- On-line manuals in the IRIS InSight Library
MGv
DESCRIPTION
-
MGv is a PostScript viewer that relies on the
Ghostscript interpreter as does Ghostview and
Gv, but has a few additional features. The most obvious
difference is the more modern interface utilizing SGI-enhanced Motif
widgets.
Functionally, MGv has a few significant advantages over Ghostview and Xpsview. First, is its ability to antialias entire pages before displaying them. Antialiasing can greatly improve the readability of PostScript text on the screen (especially small text) eliminating the often blocky and "broken" appearance. However, antialiasing is not very good for pages with images, which can significantly increase the rendering time and can even make them look worse in some cases (results will vary). Second, MGv has a more intuitive approach to zooming into a page. To magnify a particular area into a separate window, just click with the left mouse button, drag out a rectangle, release the button, and select a magnification factor from the pop-up menu. The entire page can also be magnified into the main window with the step button at the bottom. Third, only MGv has the ability to use a private colormap for its windows so that colors are not allocated from the root window's colormap. This gives it more colors to work with resulting in a much better rendering with less dithering and more colors available for other applications that do not make their own colormaps. Fourth, MGv can read compressed files (*.gz, *.Z, etc.) by uncompressing them to a temporary directory.
PLUSES
- Slick and intuitive interface.
- Sometimes displays PostScript text more accurately than Xpsview.
- Works nicely with FrameMaker, unlike Xpsview which sometimes fails when both programs try to run simultaneously.
- Marking and saving/printing individual pages out of a larger document.
- Antialiasing which greatly improves the readability of text!
- Intuitive multi-level page zooming.
- Support for private colormaps!
- Reads compressed files!
- Pan around a page larger than the window by holding down the middle mouse button and dragging.
MINUSES
- The only visual & depth combination that seems to work under IRIX 5.3 is 8-bit PseudoColor, although all the combinations do work under IRIX 6.x.
HOW TO INVOKE
- To start MGv with all antialiasing off by default:
- mgv file.ps
- or with text antialiasing initially on:
- mgv -antialias file.ps
- or with text and graphics antialiasing initially on:
- mgv -antialias -aliaseps file.eps
HINTS
-
Here's a good set of X resources to optionally put in one's
"~/.Xdefaults" file:
MGv*geometry: 900x800 MGv*autoWidth: False MGv*killChildrenAtExit: False MGv*reticuleLineWidth: 3 MGv*reticuleForeground: black MGv*fileOpen.dirMask: * MGv*resetScrollBars: none MGv*wlInstallIcon: False
These options set a reasonable default size without autosizing for the MGv window, prevent MGv from closing Netscape after using it to display the on-line help, make the lines of the zoom box selector a little wider, set the file browser filter to display all filenames by default, maintain the scrollbar positions when changing pages, and prevent the built-in default icon from being used. MGv's icon can be changed by putting an SGI RGB image (85x67 pixels) called "mgv.icon" in one's "~/.icons/" directory. To install a sample icon:cp /home/hnv/.icons/mgv.icon ~/.icons/
It may be necessary to restart the window manager in order for the icon change to take effect; select "Restart 4Dwm" from the "Main Menu", which is accessible with the right-mouse button on the screen's background. -
MGv is set to use a private colormap by default which causes
color flashing on the Personal Irises. Press
<Alt><left-click> on MGv's titlebar to
install its colormap, and press <Alt><left-click> again
on another window's titlebar to restore the previous colormap. Using a
private colormap can be disabled by setting this X resource:
MGv*wlUsePrivateColormap: False
-
The sample MGv image above shows a PostScript file displayed
with antialiasing turned on (selectable in the "Options" menu,
Ctrl+A). The samples in the
Ghostview and
Xpsview sections show the same file
without antialiasing. The differences are only visible in the full-size
images. Antialiasing can be forced on automatically by setting these X
resources:
MGv*Ghostview.antialias: True MGv*antialiasEPS: True
The first one turns antialiasing on for text and the second (together with the first) turns it on for graphics as well.
DOCUMENTATION
Xpaint
DESCRIPTION
- Xpaint is an excellent paint program with some image processing features.
PLUSES
- Easy to use.
- Handles many different image formats.
- Includes all the standard painting tools.
- Allows working on multiple images with cut and paste between them.
- Online help.
HOW TO INVOKE
- To start Xpaint by itself in 8-bit mode just enter:
- xpaint
- or in 24-bit mode:
- xpaint -24
- or with an image:
- xpaint -24 test.rgb
HINTS
- It's a good idea to always run Xpaint in 24-bit mode to preserve color accuracy. Also, Xpaint will always print a warning message if the root window is 8-bit (which it usually is by default) regardless of whether the program is instructed to run in 8-bit or 24-bit mode. This specified mode is only used for the canvas (image) windows. The main control window is always 8-bit and it takes a few colors from the root window's colormap for its icons. If there are not enough free colors in that colormap then Xpaint will abort with an error message.
DOCUMENTATION
Xpsview
DESCRIPTION
- Xpsview is a PostScript file viewer from Adobe that is bundled with the SGI's IRIX. Unlike Ghostview, Gv, and MGv, it does not use the Ghostscript interpreter, but rather the Display PostScript extension in the X server. Xpsview can cope with some non-standard PostScript files, however, mileage will vary. Experience has shown that there are some PostScript files that display fine in Xpsview while not in Ghostview, Gv, nor MGv and vice versa. Xpsview provides controls over page selection, orientation, and simple magnification.
PLUSES
- Fast and easy to use.
- Seems to be more tolerant of some unusual PostScript structures and commands than Ghostview, Gv, and MGv.
MINUSES
- Unusual conflict when using it at the same time as FrameMaker! Xpsview will sometimes refuse to start if FrameMaker is running and other times it might crash in such a way as to kill all user processes and force a logout! It is probably safest to start Xpsview first then start FrameMaker, but keep Xpsview running until FrameMaker is done. This conflict may have something to do with the fact that both programs use the X server's Display PostScript (DPS) extension.
- Cannot save individual pages out of a larger document.
- Limited zoom capability.
- No antialiasing, so small text can be difficult to read.
- Cannot create it's own private colormap.
HOW TO INVOKE
- (in IRIX) xpsview file.ps
HINTS
- Try MGv instead for a better interface and additional features.
DOCUMENTATION
XV
DESCRIPTION
- XV is a very flexible general-purpose image viewing and processing program. It can read and write many image formats (although not as many as ImageMagick) including GIF, JPEG, TIFF, PNG, PostScript, PBM/PGM/PPM, XBM, BMP, RAS, SGI RGB, TGA, FITS, and PM. XV scales images larger than the screen (1280x1024 on the SGI) so that they will fit on the screen before viewing. This has the advantage of being able to see all of a large image at once, but the disadvantage is also not being able to see all of the detail (try ImageMagick's display instead for that purpose).
PLUSES
- Easy to use.
- Handles many different image formats.
- Large variety of image processing and conversion capabilities.
- Excellent for printing images.
- "Visual Schnauzer" - thumbnail display of all images in a directory.
MINUSES
- Limited annotation and painting tools.
- Doesn't preserve transparency information in GIF images.
HOW TO INVOKE
- To start XV by itself just enter:
- xv -best24
- or with an image:
- xv -best24 test.rgb
- The "-best24" option simply chooses the best possible algorithm when converting a 24-bit image down to 8-bit.
HINTS
- When saving an image as a GIF file, XV will usually use the GIF87a format. In some situations, XV may use the GIF89a format instead in order to try to preserve certain image attributes (such as comment blocks) since it is a more flexible format than the older GIF87a. Some programs are not able to deal with GIF89a input files such as GIFMerge and WhirlGIF. In order to force an GIF87a to be written use ImageMagick's display program and save with the ".gif87" file extension.
DOCUMENTATION
- man page
- Huge 128-page PostScript document (GFDL only)
- WWW pages: Official XV page, on-line manual, and a tutorial
Command-Line Image Programs
giftrans
DESCRIPTION
- giftrans is a utility whose primary purpose is to flag a color in a GIF image as being "transparent". This transparent color will only be obvious and useful with a program such as Netscape which specifically checks for transparent colors (when putting in-line images on WWW pages). A GIF image created with giftrans will look exactly the same as the original using any regular image viewer.
HOW TO INVOKE
-
Here is an example of a GIF image before
and after
using giftrans.
- giftrans -t #000000 NOAA_logo_small_orig.gif > NOAA_logo_small.gif
DOCUMENTATION
imginfo
DESCRIPTION
- imginfo is part of SGI's ImageVision tool set and is used to quickly get information about one or more images (SGI RGB, GIFF, JPEG, TIFF, and PhotoCD formats). It prints an image's dimensions, color model, file format, and data compression, among other things.
PLUSES
- Fast and easy way to get image information.
HOW TO INVOKE
- (IRIX) imginfo test1.rgb test2.rgb ...
HINTS
- imginfo is especially useful to check if an image is stored with compression; although, it is sometimes obvious from the file's size. See rle below.
DOCUMENTATION
rgblegal
DESCRIPTION
- rgblegal adjusts the colors of an SGI RGB image for better display on video. It is basically a command-line version of Icop. In addition to adjusting for NTSC/PAL video, rgblegal can also globally reduce an image's saturation. Normally it outputs the corrected image, but it can also output an image showing only the legal/illegal pixels for a video mode with all the rest set to black.
MINUSES
- Only reads/writes SGI RGB images.
HOW TO INVOKE
- To correct an image for NTSC video:
- /home/hnv/pub/irix/anim/rgblegal -ntsc input.rgb output.rgb
- To output an image with only the NTSC-legal pixels:
- /home/hnv/pub/irix/anim/rgblegal -ntsc -legal input.rgb output.rgb
- To globally reduce an image's saturation by 50%:
- /home/hnv/pub/irix/anim/rgblegal -sat .5 input.rgb output.rgb
DOCUMENTATION
rle
DESCRIPTION
- rle saves an existing SGI RGB image with RLE (Run-Length Encoding) compression. For some reason the ImageWorks, ImgSnap, and ImgView programs do not use any compression when saving images in the SGI RGB format. Based on their composition, RLE compression can reduce image file sizes by several times so it is definitely preferable over the verbatim format that those three programs produce.
PLUSES
- Potentially big savings in disk space.
MINUSES
- Doesn't handle uncompressed TIFF images.
HOW TO INVOKE
- (no longer supported) rle input.rgb output.rgb
DOCUMENTATION
Lasted modified: Tuesday, 09-Jan-01 15:27:02 EST