Automatically animate multiple-image GIF files (see Multiple-image GIF Animation). This limits your viewing options greatly, but can be handy for slideshows and the like.

Automatically switch modes to suit image size.

When choosing an auto-mode-fit mode, add diff to each mode's width and height. For example, with a value of 20 any picture up to 820x620 will be displayed in an 800x600 mode if possible. If diff is negative, for example -20, the effect is reversed; any picture above 780x580 will be displayed in a mode with a resolution higher than 800x600 if possible.

Don't show progress indicator when loading a single file from the command-line.

Try to use a black (or nearest-to-black) background when in 8-bit modes. This can be quite nice for consistency's sake when viewing (say) a mixture of GIFs and JPEGs, but the extra pass over the loaded image slows things down slightly.

Use a blocky outline cursor in the selector, which is rather unsubtle but more obvious.

Specify how much to add to colour values to change brightness (default 0). Values less than zero decrease brightness, values greater than zero increase it. Brightness is applied after contrast by default.

(Normally enabled, use e.g. `--centre=off' to disable.) By default zgv centres pictures smaller than the screen, in whichever dimensions they are smaller. This setting gives you a way to disable this, so that pictures always start in the top-left.    

Clear the screen on exit. (Normally, zgv leaves the original screen contents intact.)

Set colour used for `black' (text) in selector; RGB values should be in the range 0-63 for this and the other colour settings below, and the three numbers should be quoted, e.g. `--col-black "10 20 30"'.

Set colour used for lowlights in selector.

Set colour used for highlights in selector.

Set colour used for background in selector.

Set colour used for tagged files in selector.

Specify how much to multiply colour values by to change contrast (default 1.0). zgv multiplies each colour's difference from grey by this number; values less than one decrease contrast, values greater than one increase it. Negative values are also allowed, and act in a similar way, but with the picture's colours inverted. Contrast is applied before brightness by default.

(Normally enabled, use `--delete-single-prompt=off' to disable.) If disabled, don't prompt for confirmation when deleting a single file.

(Normally enabled, use `--delete-tagged-prompt=off' to disable.) If disabled, don't prompt for confirmation when deleting all tagged files.

(Normally enabled, use `--dither-16col-fast=off' to disable.) By default, zgv uses a (reasonably fast) ordered dither when displaying a dithered colour image in 640x480x4 mode. But if you disable this setting, it uses error-diffused dithering (which looks better but is rather noticeably slower).

(Normally enabled, use `--fake-cols=off' to disable.) If disabled, don't fake extra greyscales and colour depth in 8-bit modes. See Increased Greyscales, for details.

Force the use of the 640x480 16-colour mode for the selector.

Force all images to be loaded as 8-bit. Normally zgv will load 24-bit images (e.g. colour JPEGs) as 24-bit if you have any modes capable of displaying the image in 15, 16, 24, or 32-bit colour.

Use low-quality colour thumbnail pictures when the file selector is using 640x480 16-colour mode. Normally zgv uses higher-quality monochrome thumbnails in this situation.

Don't recall previous cursor position in a directory when returning to it later. (This mechanism only applies when changing directory `normally'; jumping directly to another dir with `G' never does such a save/restore (see Changing Directory).)

Use `magic number'-type identification to determine which files should be listed in the file selector. This is more accurate, but very much slower. See File Type Identification, for a discussion of the tradeoffs involved.

Don't change thumbnail colours when using the file selector to make the rest of the selector look right. See Thumbnail Issues.

`walk' through the directory when updating thumbnails, moving the cursor over every single picture whether it needs updating or not. Normally, zgv completely skips any pictures which don't need updating, which makes it considerably faster on large directories and/or slow machines.

Reduce the size of the filename text in the selector. You may find this useful if you think the text is too big, or if you'd like to see more of the filename without having to press `:'.

Specify the video mode zgv should start off using for the file selector. (The default is 640x480x8 if possible, otherwise 640x480x4.) The `modespec' should be the width, height, and depth in quotes, e.g. `"640 480 8"'. See Video Modes, for details of precisely what this means. The specified depth is actually ignored in this case, as you can only choose 8-bit modes for the selector.

Thicken the text (filenames etc.) in the file selector (and elsewhere). (Note that if line-text has been enabled, then fs-thick-text only has an effect if block-cursor is on as well.)

Set the gamma adjustment used (see Gamma Adjustment). This also sets the `initial value' used when resetting the gamma adjustment. The default is 1.0, i.e. no adjustment.

GNU has POSIXLY_CORRECT for compatibility with silly POSIX misfeatures, and zgv has...

Display a list of options and a terse description of what the options do.

When loading a single file from the command-line, ignore (some) errors. Only meaningful for PNG currently.

Specify how to read JPEGs when creating thumbnails. Style `1' is the quickest, but sometimes generates rather fuzzy/blocky thumbnails; `2' is fairly cautious (and the default), but still quite fast; `3' is an extremely cautious and slow method.

Set JPEG speed/quality tradeoff. Type `1' is slow but accurate; `2' is faster but not as accurate (and the default); `3' is the fastest but the least accurate.

Draw text by drawing lines rather than using bitmap fonts. This looks worse but is faster.

Enable mouse support in zgv. /dev/mouse must be (usually a symlink to) the mouse device. The actual configuration of the mouse should be done via svgalib's config file libvga.config; see the man page for that for details.

Set the ratio of `mouse pixels' to onscreen pixels. The larger the number, the slower the mouse moves, and vice versa. (However, the number must be greater than zero.) If the mouse pointer moves at the wrong speed for your tastes, play about with this setting and you should be able to fix it.

Selects the resolution used for Photo-CD files; 1=192x128, 2=384x256, 3=768x512 (default), 4=1536x1024, 5=3072x2048. (This setting only has an effect if Photo-CD support was enabled at compile-time.)

This one needs some background to fully explain --- greyscale files are normally displayed in 8-bit modes, which due to VGA's limited palette means that only 64 greyscales can be shown (zgv normally fakes extra ones, though; see Increased Greyscales). But for people who work with greyscale files and have 24/32-bit video modes available this can be frustrating, as 24/32-bit modes display 256 greyscales. For this reason, using the `--pgm-truecol' option enables a special-case hack to read (only) PGM files as if they were 24-bit. Using a 24/32-bit mode then gives you 256 greyscales. (Be careful to avoid 15/16-bit modes as these will only give 32! See Drawbacks of 15/16-bit Modes.)

If seconds is >0, then any picture displayed is re-read and redisplayed (without clearing the screen first) every seconds seconds. If it is `-1', then the picture is re-read as often as possible. If it's `0' (zero), the picture is only read once --- the default. Unless this option has suddenly inspired you to write an interesting little shell script, you're unlikely ever to have a use for it. :-)

Normally, any brightness modification is applied after applying any contrast. Enabling this reverses the order.

(Normally enabled, use `--revert-orient=off' to disable.) If disabled, orientation (flip/mirror/rotate) state is retained between pictures.

(Normally enabled, use `--revert-scale=off' to disable.) If disabled, scaling is retained between pictures.

(Normally enabled, use `--scrollbar=off' to disable.) If disabled, don't show a scrollbar below the selector.

Cause zgv to output the x and y offsets, and width and height of the section of the image being displayed when you exit zgv. Can be useful for things like `pnmcut `zgv -s input.ppm` input.ppm > output.ppm'.

Print names of tagged files on exit. This can be useful in constructions something like `mv `zgv -T` /tmp', which moves to /tmp only the files you select.

Show any .xvpics directories so that the thumbnails can be viewed even if the files they referred to no longer exist. (However, it's usually easier to simply start zgv in the .xvpics dir.)

Set time to wait in seconds before loading the next picture in a slideshow. The default is 4.

Loop in slideshows `forever' (or rather, until you exit).

Randomise picture order in slideshows. Due to the shuffling approach taken, there will be no repeats or omissions.

Give a dithered colour image in 640x480x4 mode when in the viewer (see The Viewer 640x480x4 Mode), rather than greyscale.

Specify the video mode zgv should start off using for the viewer. The default is generally 640x480x8, but it's actually a bit more complicated than that (see Default Video Mode). The `modespec' should be the width, height, and depth in quotes, e.g. `"640 480 8"'. See Video Modes, for details of precisely what this means.

(Normally enabled, use `--visual=off' to disable.) If disabled, no thumbnails are shown.

enables vkludge, which smoothes slightly when `zooming' a big picture down to screen size, and also when in 320x400 and 360x480 modes.

Show version number.

Write the file as a PPM to stdout rather than viewing it. (This only works if you run zgv on a single file, specified on the command-line.) You're usually better off using a dedicated image-converting program, though.

Makes zgv acts a bit more like xzgv, at least in terms of the keypresses it supports (see xzgv Compatibility).

Enable zoom mode, which resizes the picture to fit the screen. See Zoom Mode.

When in zoom mode, only reduce pictures to fit; i.e. make big pictures viewable all-at-once while leaving small picures intact.

Gives online help. This lists some of the most commonly-used keypresses in the current context.

Quit zgv normally.

Quit zgv in a rather immediate and nasty way, by sending SIGINT. (This is actually dealt with by svgalib.) You should only use ^C to quit if zgv appears to lock up or takes an unbearably long time to do something.

(Technically it may not be `^C' which sends SIGINT, but you would have to have a strange setup for this to be the case.)

Create thumbnails for any files which don't have them, and update thumbnails which are older than than the corresponding file. While this is going on, the text updating index of prefixes the usual display of the current directory's name.

You can press `Esc' while the update is in progress to abort it; zgv will stop once it has finished the thumbnail it is currently working on (if any).

If you switch consoles while the update is in progress, it will continue to run `in the background'. When you switch back, if the update is still in progress, it may look as though zgv is doing nothing (or the screen may look a bit confusing) for some time. The reason is that the screen is not updated unless zgv is running on the currently displayed console (this is unfortunately necessary). The screen is redrawn when the current thumbnail has been dealt with.

Create/update thumbnails for all files in the current directory and all subdirectories --- in other words, do a recursive update. This can take some time, so you are prompted to confirm that you really want to do this (see Dialog Boxes). As above, it will continue running `in the background' if you switch consoles, and you can press `Esc' to abort.

Create thumbnails for subdirectories. Don't confuse this with the recursive update; this generates thumbnails for the directories themselves, not the files within them. (Most people probably won't want to bother with these, as they're not as helpful as you might think.) These consist of the first four files in the subdir, squeezed together into a single thumbnail. There is (currently) no `update' mechanism for subdir thumbnails --- all of them are newly created each time you press `d'.

Move up. Moving up from a topmost entry moves to the bottom of the previous column.

Move down. Moving down from a bottommost entry moves to the top of the next column.

Move left one column.

Move right one column.

Move the cursor back (nearly) a page.

Move the cursor forward (nearly) a page.

Move the cursor to the start of the list.

Move the cursor to the end of the list.

Move the cursor to the first filename starting with the next key pressed, which would generally be a letter or number. Case is significant; `a' and `A' are different.

If no files start with the specified character, it moves to the first file which starts with a later char (in asciibetical order). If there are none for which this is the case, it moves to the last file --- unless there are no files (just directories), in which case it has no effect.

View a picture file, or if the cursor is on a subdirectory, make that the current directory. A progress indicator is shown when reading in a file --- while this is onscreen, you can use `Esc' to abort.

Move the cursor left. (An underline character shows the cursor position.)

Move the cursor right.

Move the cursor to the start of the line.

Move the cursor to the end of the line.

Toggle insert/overwrite mode. (Insert mode is the default.) In insert mode, characters you type are inserted at the cursor position. In overwrite mode, they replace the existing chars.

Delete char to the left of the cursor. (This assumes `Backspace' really generates a `DEL', which is the usual setup on Linux. Note that `Backspace' is (usually) the key above the main `Enter' key; it is often labelled simply as an arrow.)

Delete the char the cursor is on.

Tag file.

Untag file. Note that this is `n' (for `no tag', er, or something like that); `u' would be more logical, but that is used for updating thumbnails.

Tag all files.

Untag all files. This is on `N' rather than `U' for consistency.

Toggle the tag status of the file --- if it's tagged, untag it; if it's untagged, tag it.

View the tagged files as a slideshow. (`Tab' is usually the key above `Caps Lock', which is often labelled with two arrows.)

Copy tagged files (or the current file) to a given directory. zgv asks for the destination directory using a dialog (see Dialog Boxes) and copies the files there. If it comes to copy a file but there is an existing file in the dir with the same name, the file is not copied and nor are any of the remaining files.

Move tagged files (or the current file) similarly.

Delete tagged files (or the current file) similarly. In this case, there's obviously no need to specify any directory :-) but you're prompted before deletion starts (unless this is disabled, see Configuring zgv). It also deletes thumbnails, for those files which have them.

Rename the current file or directory --- zgv will refuse to overwrite any existing files/directories. The new name must remain in the current directory. (See Copying/Moving/Deleting Files, for how to move a file to a different directory (albeit keeping the same name).)

Go to a specified directory. zgv asks for the destination directory using a dialog box which you should type the dir's name into (see Dialog Boxes), and moves to that directory if it exists.

If the directory turns out to be unreadable --- i.e. you do not have permission to read it --- zgv resorts to going to your home directory. (This is actually a general mechanism in zgv, but this command is the most likely trigger of it.) If that in turn is unreadable, zgv gives up in disgust and exits. :-)

Sort by name. This is the default.

Sort by size. The biggest files are listed last.

Sort by last-modified date/time. The newest files are listed last.

Sort by extension.

Toggle display of thumbnails (default is on). The without-thumbnails display can sometimes be useful for navigating around large directories (many filenames are shown onscreen at once), and it is of course faster.

Toggle scrollbar on/off (default is on). The scrollbar shows which part and which proportion of the list is currently being shown onscreen, and when mouse support is enabled can be used to move around the list.

Toggle shuffling (randomising) of slideshows. See Slideshows.

Toggle looping in slideshows. See Slideshows.

Toggle use of `magic numbers' (identifiers at the start of a file) to pick which files in a directory to list in the selector. The usual method of doing this is based on the file's extension (see File Type Identification, which is much faster but won't catch e.g. files without extensions.

If the file selector is running in 16-colour mode (it usually doesn't unless zgv has no choice --- see 16-colour File Selector), toggle between greyscale (default) and colour thumbnails.

Delete (only) the file the cursor is on. Asks for confirmation (unless this is disabled, see Configuring zgv). It also deletes the file's thumbnail, if it has one. See Copying/Moving/Deleting Files, for a more general command which deletes all tagged files.

Show various details about the file the cursor is on; the (full) filename, the size in kilobytes, width/height if recorded in any thumbnail, last-modified date, etc. You can also use the `;' key to get this.

Show the number of (picture) files in the current directory, and the number of tagged files (see Tagging).

Rescan the directory contents, and redraw the screen.

Kill mouse --- disable mouse for the rest of this zgv session. (It prompts to check if you really want to do so.) This can be useful if you have the mouse enabled in a config file, so that zgv always starts up with the mouse on, but you're currently using just the keyboard. In such a situation the mouse pointer can be a bit annoying. This command lets you disable the mouse completely for the current zgv process.

Select 640x480 mode. This is the default.

Select 800x600 mode.

Select 1024x768 mode.

Select 1280x1024 mode.

Exit the viewer.

If you got to the viewer from the file selector, you're returned there; if you bypassed the file selector (by running zgv with a file (or files) to view specified on the command-line --- see Options) then exiting the viewer also exits zgv.

Move up 100 pixels. `k' and `q' move up 10 pixels.

Move down 100 pixels. `j' and `a' move down 10 pixels.

Move left 100 pixels. `h' and `o' move left 10 pixels.

Move right 100 pixels. `l' and `p' move right 10 pixels.

Move up (nearly) a screenful. (It moves 90% of the screen height.)

Move down (nearly) a screenful.

Move left (nearly) a screenful. (It moves 90% of the screen width.)

Move right (nearly) a screenful.

Move to the top-left of the picture.

Move to the bottom-right of the picture.

Toggle zoom mode.

When in zoom mode, only reduce pictures to fit. This can be useful when going through a lot of unpredictably-sized pictures, as it means that you can see all of a big picture easily without also meaning that tiny little icons assume a scale of Biblical proportions. :-)

Toggle vkludge, which enables appropriate smoothing when zoom mode is reducing a picture to fit the screen. It also enables similar smoothing for non-zoomed pictures in 320x400x8 and 360x480x8 modes. See Virtual Modes.

Resume `normal' display --- disables zoom mode (and scaling mode).

Toggle auto-mode-fit mode. Usually this only takes effect when a picture is loaded (so that manual mode switching still works), but when you enable it zgv does a one-off auto-mode-fit on the current picture. (Note also that disabling it leaves you in the current mode, so that has no obvious effect; for this reason, the picture is redrawn (as a visual cue that you haven't just been ignored :-)).)

Increase the ratio by adding one --- this leads to ratios of 2:1, 3:1, 4:1...

Increase the ratio by doubling it --- leads to ratios of 2:1, 4:1, 8:1...

Decrease the ratio by subtracting one.

Decrease the ratio by halving it.

Toggle interpolation in scaling mode.

Toggle off-by-one interpolation (disabled by default). Using this off-by-one method gives incorrect results, but this can occasionally be useful at ratios of 2:1 and 3:1 for relatively low-quality JPEGs.

`Mirror' the picture (flip it horizontally).

`Flip' the picture (flip it vertically).

Rotate the picture 90 degrees clockwise.

Rotate the picture 90 degrees anti-clockwise. (This is a little slower as it works by effectively doing `r' then `f' then `m'.)

Restore the picture orientation to normal. This undoes the effect of any mirrors, flips, and/or rotations.

Re-use the previous picture's orientation for this picture.

Save the current picture orientation, making all pictures viewed until you press `Esc' use it. (The orientation reverts to normal after that, though.)

Decrease contrast.

Increase contrast.

Decrease brightness.

Increase brightness.

Reset contrast and brightness to normal. (`*' is also supported, for hysterical raisins.)

Reverse the order in which brightness and contrast are applied.

Set gamma adjustment to 1.0, i.e. no adjustment. This is the default setting.

Set gamma adjustment to 2.2. This is useful for viewing linear-gamma files (one classic example being raytracer output) on an average PC monitor.

Set gamma adjustment to 1 divided by 2.2, i.e. roughly 0.45. This is useful for the reverse --- viewing average-PC-monitor-gamma files on a linear-gamma display. Historically I believe the classic example would have been viewing PC files on a Mac, but I don't know how true that is these days.

Set gamma adjustment to its initial value, as specified by a `-G' command-line option (see Options) or gamma config file setting (see Configuring zgv). The default value used if none was specified is 1.0.

Decrease gamma adjustment (divide it by 1.05).

Increase gamma adjustment (multiply it by 1.05).

Toggle whether to fake some extra greyscales/colours in 8-bit modes.

View previous file in dir, without progress indicator. (In slideshow, move to next file without waiting.)

View next file in dir, without progress indicator. (In slideshow, move to next file without waiting.)

Tag current file, then view next file in dir, without progress indicator. (In slideshow, move to next file without waiting; it has no tagging effect during a slideshow.)

View previous file in dir, with progress indicator. (In slideshow, acts like `Esc'.)

View next file in dir, with progress indicator. (In slideshow, acts like `Esc'.)

Show file details, including such things as the filename, size, and width/height. This is almost identical to the equivalent command in the selector (see Other File Sel Commands); the only difference is that you can't use `;' to get this in the viewer, and the viewer doesn't depend on thumbnails for the width/height info.

Pause slideshow, leaving you on the current image until you resume. You can still abort early with `Esc', go to the next image with `Enter', or in fact use any viewer commands at all.

Resume slideshow. If the timer has already run out (it keeps running while paused), this will go straight to the next image without any further delay, other than that needed to read the new picture.

Enter animation mode. (I don't know what the `e' stands for either. :-)) In this mode the normal viewer keys have no effect, and instead, a more limited set of keys are supported:

Stop the animation and return to the viewer. If auto-animation mode is enabled, it exits the viewer too.

Pause (or unpause) the animation.

Skip to the next frame. Generally only useful when paused.

List which key combination selects which video mode.

Select the next smaller (lower-res) mode.

Select the next bigger (higher-res) mode. Both these mode-changing keys have the limits on modes selected that auto-mode-fit has (see Auto-mode-fit).

Select 640x480x4 mode. This emulates an 8-bit mode. See The Viewer 640x480x4 Mode.

Select 320x200x8 mode.

Select 320x240x8 mode.

Select 320x240x24 mode. (`^' is often on shift-6.)

Select 320x400x8 mode. This emulates a 640x400 mode. See Virtual Modes.

Select 360x480x8 mode. This emulates a 720x480 mode. See Virtual Modes.

Select 640x480x8 mode.

Select 800x600x8 mode.

Select 1024x768x8 mode.

Select 1280x1024x8 mode.

Select 320x200x15 mode.

Select 320x200x16 mode.

Select 320x200x24 mode.

Select 640x480x15 mode.

Select 640x480x16 mode.

Select 640x480x24 mode.

Select 800x600x15 mode.

Select 800x600x16 mode.

Select 800x600x24 mode.

Select 1024x768x15 mode.

Select 1024x768x16 mode.

Select 1024x768x24 mode.

Select 1280x1024x15 mode.

Select 1280x1024x16 mode.

Select 1280x1024x24 mode.

Select 1152x864x8 mode.

Select 1152x864x15 mode.

Select 1152x864x16 mode.

Select 1152x864x24 mode.

Select 1600x1200x8 mode.

Select 1600x1200x15 mode.

Select 1600x1200x16 mode.

Select 1600x1200x24 mode.

If in 640x480x4 mode, toggle between greyscale and colour.

If in 640x480x4 mode and using colour dithering, toggle between ordered and error-diffused dither.

View a picture file, or if the cursor is on a subdirectory, make that the current directory. (Like the native `Enter', which still works.)

Untag file.

Tag file.

(i.e. Alt-minus) Untag all files.

(i.e. Alt-equals) Tag all files.

Rename file.

Delete file.

Exit zgv.

View previous file in dir.

View next file in dir.

Tag current file, then view next file in dir.

(In short, `b'/`Space'/`Ctrl-Space' act like the native `Backspace'/`Enter'/`Space'. The same mappings also apply when animating a multiple-image GIF file (see Multiple-image GIF Animation).)

Exit viewer (i.e. `close file').

Restore the picture orientation to normal. This undoes the effect of any mirrors, flips, and/or rotations. (Like the native `Alt-n'.)