@vindex delete-single-prompt@item --delete-single-prompt(Normally enabled, use @code{--delete-single-prompt=off} to disable.) Ifdisabled, don't prompt for confirmation when deleting a single file.@vindex delete-tagged-prompt@item --delete-tagged-prompt(Normally enabled, use @code{--delete-tagged-prompt=off} to disable.)If disabled, don't prompt for confirmation when deleting all taggedfiles.@vindex dither-16col-fast@item --dither-16col-fast(Normally enabled, use @code{--dither-16col-fast=off} to disable.) Bydefault, zgv uses a (reasonably fast) ordered dither when displaying adithered colour image in 640x480x4 mode. But if you disable thissetting, it uses error-diffused dithering (which looks better but israther noticeably slower).@vindex fake-cols@item --fake-cols(Normally enabled, use @code{--fake-cols=off} to disable.) If disabled,don't fake extra greyscales and colour depth in 8-bit modes.@xref{Increased Greyscales}, for details.@vindex force-fs-16col@item --force-fs-16colForce the use of the 640x480 16-colour mode for the selector.@item -j@vindex force-viewer-8bit@itemx --force-viewer-8bitForce all images to be loaded as 8-bit. Normally zgv will load 24-bitimages (e.g. colour JPEGs) as 24-bit if you have any modes capable ofdisplaying the image in 15, 16, 24, or 32-bit colour.@vindex fs-16col-colour-thumbnails@vindex fs-16col-color-thumbnails@item --fs-16col-colour-thumbnails@itemx --fs-16col-color-thumbnailsUse low-quality colour thumbnail pictures when the file selector isusing 640x480 16-colour mode. Normally zgv uses higher-qualitymonochrome thumbnails in this situation.@vindex fs-ignore-old-pos@item --fs-ignore-old-posDon't recall previous cursor position in a directory when returning toit later. (This mechanism only applies when changing directory`normally'; jumping directly to another dir with @kbd{G} never does sucha save/restore (@pxref{Changing Directory}).)@vindex fs-magic@item --fs-magicUse `magic number'-type identification to determine which files shouldbe listed in the file selector. This is more accurate, but very muchslower. @xref{File Type Identification}, for a discussion of thetradeoffs involved.@vindex fs-perfect-cols@item --fs-perfect-colsDon't change thumbnail colours when using the file selector to make therest of the selector look right. @xref{Thumbnail Issues}.@vindex fs-slow-thumbnail-update@item --fs-slow-thumbnail-update`walk' through the directory when updating thumbnails, moving the cursorover every single picture whether it needs updating or not. Normally,zgv completely skips any pictures which don't need updating, which makesit considerably faster on large directories and/or slow machines.@vindex fs-small-text@item --fs-small-textReduce the size of the filename text in the selector. You may find thisuseful if you think the text is too big, or if you'd like to see more ofthe filename without having to press @code{:}.@vindex fs-start-mode@item --fs-start-mode @var{modespec}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.@code{"640 480 8"}. @xref{Video Modes}, for details of precisely whatthis means.@item -t@vindex fs-thick-text@itemx --fs-thick-textThicken the text (filenames etc.) in the file selector (and elsewhere).(Note that if @samp{line-text} has been enabled, then@samp{fs-thick-text} only has an effect if @samp{block-cursor} is on aswell.)@item -G @var{val}@vindex gamma@itemx --gamma @var{val}Set the gamma adjustment used (@pxref{Gamma Adjustment}). This also setsthe `initial value' used when resetting the gamma adjustment. Thedefault is 1.0, i.e. no adjustment.@vindex gnulitically-correct@item --gnulitically-correctGNU has @samp{POSIXLY_CORRECT} for compatibility with silly POSIXmisfeatures, and zgv has@dots{}@item -h@c not config var@itemx --helpDisplay a list of options and a terse description of what the optionsdo.@item -i@vindex ignore-errors@itemx --ignore-errorsWhen loading a single file from the command-line, ignore (some) errors.Only meaningful for PNG currently.@vindex jpeg-index-style@item --jpeg-index-style @var{style}Specify how to read JPEGs when creating thumbnails. Style @code{1} isthe quickest, but sometimes generates rather fuzzy/blocky thumbnails;@code{2} is fairly cautious (and the default), but still quite fast;@code{3} is an extremely cautious and slow method.@item -J @var{type}@vindex jpeg-speed@itemx --jpeg-speed @var{type}Set JPEG speed/quality tradeoff. Type @code{1} is slow but accurate;@code{2} is faster but not as accurate (and the default); @code{3} isthe fastest but the least accurate.@vindex line-text@item --line-textDraw text by drawing lines rather than using bitmap fonts. This looksworse but is faster.@item -M@vindex mouse@itemx --mouseEnable mouse support in zgv. @file{/dev/mouse} must be (usually asymlink to) the mouse device. The actual configuration of the mouseshould be done via svgalib's config file @file{libvga.config}; see theman page for that for details.@vindex mouse-scale@item --mouse-scale @var{scale}Set the ratio of `mouse pixels' to onscreen pixels. The larger thenumber, the slower the mouse moves, and vice versa. (However, the numbermust be greater than zero.) If the mouse pointer moves at the wrongspeed for your tastes, play about with this setting and you should beable to fix it.@vindex pcd-res@item --pcd-res @var{resnum}Selects the resolution used for Photo-CD files; 1=192x128, 2=384x256,3=768x512 (default), 4=1536x1024, 5=3072x2048. (This setting only has aneffect if Photo-CD support was enabled at compile-time.)@item -g@vindex pgm-truecol@itemx --pgm-truecolThis one needs some background to fully explain --- greyscale files arenormally displayed in 8-bit modes, which due to VGA's limited palettemeans that only 64 greyscales can be shown (zgv normally fakes extraones, though; @pxref{Increased Greyscales}). But for people who workwith greyscale files and have 24/32-bit video modes available this canbe frustrating, as 24/32-bit modes display 256 greyscales. For thisreason, using the @code{--pgm-truecol} option enables a special-casehack to read (only) PGM files as if they were 24-bit. Using a 24/32-bitmode then gives you 256 greyscales. (Be careful to avoid 15/16-bit modesas these will only give 32! @xref{Drawbacks of 15/16-bit Modes}.)@vindex reverse-bc-order@item --reverse-bc-orderNormally, any brightness modification is applied after applying anycontrast. Enabling this reverses the order.@vindex revert-orient@item --revert-orient(Normally enabled, use @code{--revert-orient=off} to disable.) Ifdisabled, orientation (flip/mirror/rotate) state is retained betweenpictures.@vindex revert-scale@item --revert-scale(Normally enabled, use @code{--revert-scale=off} to disable.) Ifdisabled, scaling is retained between pictures.@vindex scrollbar@item --scrollbar(Normally enabled, use @code{--scrollbar=off} to disable.) If disabled,don't show a scrollbar below the selector.@vindex show-xvpics-dir@item --show-xvpics-dirShow any @file{.xvpics} directories so that the thumbnails can be viewedeven if the files they referred to no longer exist. (However, it'susually easier to simply start zgv in the @file{.xvpics} dir.)@item -T@c not config var@itemx --show-taggedPrint names of tagged files on exit. This can be useful in constructionssomething like @code{mv `zgv -T` /tmp}, which moves to @file{/tmp} onlythe files you select.@item -S @var{delay}@vindex slideshow-delay@itemx --slideshow-delay @var{delay}Set time to wait in seconds before loading the next picture in aslideshow. The default is 4.@item -l@vindex slideshow-loop@itemx --slideshow-loopLoop in slideshows `forever' (or rather, until you exit).@item -R@vindex slideshow-randomise@vindex slideshow-randomize@itemx --slideshow-randomise@itemx --slideshow-randomizeRandomise picture order in slideshows. Due to the shuffling approachtaken, there will be no repeats or omissions.@vindex viewer-16col-colour@vindex viewer-16col-color@item --viewer-16col-colour@itemx --viewer-16col-colorGive a dithered colour image in 640x480x4 mode when in the viewer(@pxref{The Viewer 640x480x4 Mode}), rather than greyscale.@item -m @var{modespec}@vindex viewer-start-mode@itemx --viewer-start-mode @var{modespec}Specify the video mode zgv should start off using for the viewer. Thedefault is generally 640x480x8, but it's actually a bit more complicatedthan that (@pxref{Default Video Mode}). The `modespec' should be thewidth, height, and depth in quotes, e.g. @code{"640 480 8"}. @xref{VideoModes}, for details of precisely what this means.@vindex visual@item --visual(Normally enabled, use @code{--visual=off} to disable.) If disabled, nothumbnails are shown.@item -k@vindex vkludge@itemx --vkludgeenables vkludge, which smoothes slightly when `zooming' a big picturedown to screen size, and also when in 320x400 and 360x480 modes.@c not config var@item --versionShow version number.@vindex xzgv-keys@item --xzgv-keysMakes zgv acts a bit more like xzgv, at least in terms of the keypressesit supports (@pxref{xzgv Compatibility}).@item -z@vindex zoom@itemx --zoomEnable zoom mode, which resizes the picture to fit the screen.@xref{Zoom Mode}.@vindex zoom-reduce-only@item --zoom-reduce-onlyWhen in zoom mode, only @emph{reduce} pictures to fit; i.e. make bigpictures viewable all-at-once while leaving small picures intact.@end tableIf zgv is started with @code{zgv @var{file}}, zgv auto-loads the file(bypassing the file selector), and exits when you exit from viewing thepicture. (By the way, this also makes it possible to view single fileswithout the usual extensions such as @file{.gif}, etc. @xref{File TypeIdentification}.)If started with @code{zgv @var{file file2 ...}} --- i.e. with more thanone filename --- zgv works in a similar way, except the multiple filesare shown as a slideshow, one after the other. You may want to specify@code{-l} so that zgv will loop around these pictures until @kbd{Esc} ispressed, and the @code{-R} option to shuffle (randomise) the pictureorder may also be of interest.If started with @code{zgv @var{start-dir}}, zgv starts up with the usualfile selector, but with the current directory being the one specified.Settings which are either on or off (boolean) are, as you might expect,enabled by using e.g. @code{-z} or @code{--zoom}. However, there's analternative long-option form for setting these, resembling how they'reset in config files --- the syntax is @code{--option=@var{state}}, where@var{state} is @code{on}/@code{y}/@code{yes}/@code{1} to enable theoption, or @code{off}/@code{n}/@code{no}/@code{0} to disable it. Themost useful thing about this is that it allows you to disable optionswhich were previously enabled, by using e.g. @code{--zoom=off}.(Readers used to the way GNU-style long options work should note that,since this @code{on}/@code{off}/etc. arg is optional, you can't use the@code{--option arg} form in this case; it must be @code{--option=arg}for it to work.)@node  Online help, The File Selector, Invoking zgv, Top@comment  node-name,  next,  previous,  up@chapter Online help@cindex online help@cindex help, onlineOnline help (of a sort) is available in both the file selector andviewer:@table @kbd@kindex ?@item ?Gives online help. This lists some of the most commonly-used keypressesin the current context.@end tableIn the viewer, you can also get a list of which key combinations selectwhich video modes. @xref{Selecting a Video Mode}.@node  The File Selector, The Viewer, Online help, Top@comment  node-name,  next,  previous,  up@chapter The File Selector@c XXX could do with synonyms for `selector' here...@cindex file selector@cindex the file selector@cindex selectorUsually, on starting up zgv, you will enter the file selector, whichlets you pick files to view (among other things). This lists thesubdirectories and picture files in the current directory, along withsmall `thumbnail' versions of the pictures if they exist.@menu* Exiting zgv::                 Why would you want to? :-)* Thumbnails::                  How to create thumbnails, and how they                                  work.* Screen Layout::               The file selector lists dirs/files.* Moving Around The List::      How to move the cursor.* Viewing a File::              How to view a single file.* Dialog Boxes::                How zgv reports errors and asks you things.* Tagging::                     You can tag (mark) multiple files, then                                  view/copy/move/delete them.* Renaming a File::             Renaming a single file or directory.* Changing Directory::          As well as the normal dir-by-dir way,                                  you can jump directly to a directory.* Changing the Sorting Order::  Files can be sorted by name,                                  `extension', size, and date/time.* File Selector Toggles::       Some options can be changed while zgv is                                  running.* Other File Sel Commands::     Miscellaneous operations.* Showing More Files::          You can use different video modes for the                                  file selector, showing more files at                                  once.* 16-colour File Selector::     If 640x480 256-colour mode is absent                                  thumbnails don't look as good, but you                                  can choose between monochrome and                                  colour approximations.@end menu@node  Exiting zgv, Thumbnails, The File Selector, The File Selector@comment  node-name,  next,  previous,  up@section Exiting zgv@cindex exiting zgv@cindex quitting zgv@cindex leaving zgvExiting zgv can be achieved two ways:@table @kbd@kindex Esc (Selector)