[ViewVC] Annotation of: cvs/CV/README

NAME
    cv - a fast gtk+ image viewer loosely modeled after XV

SYNOPSIS
       cv [file...]

FEATURES
    CV is supposed to work similar to the venerable XV image viewer, just
    faster. Why faster?

    * optimized directory scanning algorithm
        The directory scanning in CV uses some tricks that - on most modern
        filesystems - makes it possible to detect filetypes faster than
        stat()'ing every file. This makes CV suitable for directories with
        lots of files (10000+).

        This algorithm is quite unprecise - it doesn't make a difference
        between files, device nodes, symlinks and the like, and filetype
        detection is done using the file extension only.

        On the positive side, it is usually many orders of magnitude faster
        than traditional scanning techniques (good for directories with
        10000 or 100000+ files).

    * queuing for all time-consuming background tasks
        All tasks, such as unlinking files or generating thumbnails, that
        can be done in the background will be done so - no waiting required,
        even when changing directories.

    * use of asynchronous I/O
        CV tries to use asynchronous I/O whereever it makes sense, for
        example while scanning directories, waiting for stat data, unlinking
        files or generating thumbnails. This usually decreases scanning
        times for large directories a bit (especially on RAID devices and
        over NFS) and makes CV much more interactive.

    * fast image loading
        The time span between the user issuing a command and displaying the
        new image should be as small as possible. CV uses optimized
        (especially for JPEG) loading functions and sacrifices some quality
        (e.g no gamma correction, although this might change) to achieve
        this speed.

    * fast thumbnail creation
        Thumbnail creation uses both CPU and Disk-I/O. CV interleaves both,
        so on modern CPUs, thumbnailing is usually limited by I/O speed.
        Thumbnail creation for JPEGs has been specially optimized and can
        even take advantage of multiple CPUs.

    * minimum optical clutter
        CV has no menus or other user interface elements that take up a lot
        of screen space (or are useful for beginning users). The schnauzer
        windows can also be somewhat crowded.

        The point of an image viewer is viewing images, not a nice GUI. This
        is similar to XV's behaviour.

    * efficient (and hard to learn) user interface
        CV uses key combinations. A lot. If you are an experienced XV user,
        you will find most of these keys familiar. If not, CV might be hard
        to use at first, but will be an efficient tool later.

    * multi-window GUI
        CV doesn't force you to use a specific layout, instead it relies on
        your window manager, thus enabling you to chose whatever layout that
        suits you most.

    * i18n'ed filename handling throughout
        As long as glib can recognize your filename encoding (either UTF-8
        or locale-specific, depending on the setting of G_BROKEN_FILENAMES)
        and you have the relevant fonts, CV will display your filenames
        correctly.

    * extensible through plug-ins
        I have weird plug-ins that access remote databases to find a
        directory. This is not likely to be of any use to other people.
        Likewise, others might have weird requirements I cannot dream of.

    * filename clustering
        Among the standard plug-ins is a filename clustering plug-in, that
        (in case of tens of thousands images in one directory) might be able
        to cluster similar names together.

DESCRIPTION
  THE IMAGE WINDOW
    You can use the following keys in the image window:

     q            quit the program
     <            half the image size
     >            double the image size
     ,            shrink the image by 10%
     .            enlarge the image by 10%
     n            reset to normal size
     m            maximize to screensize
     M            maximize to screensize, respecting image aspect
     ctrl-m       toggle maxpect-always mode
     u            uncrop
     r            set scaling mode to 'nearest' (fastest)
     s            set scaling mode to 'bilinear' (default)
     shift-s      set scaling mode to 'hyper' (slowest)
     t            rotate clockwise 90Â°
     T            rotate counterclockwiseÂ°
     ctrl-v       open a new visual schnauzer window for the current dir
     ctrl-e       run an editor ($CV_EDITOR or "gimp") on the current image
     ctrl-p       fire up the print fialog
     escape       cancel a crop action

    And when playing movies, these additional keys are active:

     left         rewind by 10 seconds
     right        forward by 10 seconds
     down         rewind by 60 seconds
     up           forward by 60 seconds
     pg_up        rewind by 600 seconds
     pg_down      forward by 600 seconds
     o            toggle on-screen display
     p            pause/unpause
     escape       stop playing
     9            turn volume down
     0            turn volume up

    Any other keys will be sent to the default schnauzer window, which can
    be toggled on and off by right-clicking into the image window.

    Left-clicking into the image window will let you crop the image (usually
    to zoom into large images that CV scales down).

  THE VISUAL SCHNAUZER
    You can use the following keys in the schnauzer window:

     ctrl-space,
     space        move to and display next image
     ctrl-backspace,
     backspace    move to and display previous image
     ctrl-return,
     return       display selected picture, or enter directory

     cursor keys  move selection
     page-up      move one page up
     page-down    move one page down
     home         move to first file
     end          move to last file

     ctrl-a       select all files
     ctrl-shift-a select all files currently displayed in the schnauzer window
     ctrl-d       delete selected files WITHOUT ASKING AGAIN
     ctrl-g       force generation of thumbnais for the selected files
     ctrl-s       rescan current direcory or files updates/deletes etc.
     ctrl-u       update selected (or all) icons if neccessary
     ctrl-l       don't use, will become a plug-in eventually

     ^            go to parent directory (caret).

     0-9,
     a-z          find the first filename beginning with this letter

    Right-clicking into the schnauzer window displays a pop-up menu with
    additional actions.

FILES
    When starting, CV runs the .cvrc file in your $HOME directory as if it
    were a perl script. in that, you will mostly load plug-ins.

    Example:

       system "fping -q -t 10 ether"
         or require "/fs/cv/cvplugin.pl";

    This will load a plug-in, but only if the machine *ether* is reachable
    (supposedly the plug-in is networked in some way :).

ENVIRONMENT
    CV_EDITOR
        The program that gets executed when the user presses "CTRL-e" in the
        Schnauzer or image window. The default is "gimp".

    CV_PRINT_DESTINATION
        The default (perl-style) destination to use in the print dialog.

    CV_TRASHCAN
        When set, must point to a directory where all files that are deleted
        are moved to. If unset, files that are deleted are really being
        deleted.

SECURITY CONSIDERATIONS
    CV uses Pixbuf to load non-JPEG images. Pixbuf is not considered safe
    for this purpose, though (from the gtk-2.2 release notes):

    "While efforts have been made to make gdk-pixbuf robust against invalid
    images, using gdk-pixbuf to load untrusted data is not recommended, due
    to the likelyhood that there are additional problems where an invalid
    image could cause gdk-pixbuf to crash or worse."

BUGS/TODO
     Lots of functionality is missing.

     Pixbuf doesn't always honor G_BROKEN_FILENAMES, so accessing files with
     names incompatible with utf-8 might fail.

     rotate on disk
     lots of ui issues
     save(?)
     preferences

AUTHOR
    Marc Lehmann <cv@plan9.de>.

Revision:	1.3
Committed:	Wed Sep 7 17:17:39 2005 UTC (18 years, 8 months ago) by root
Branch:	MAIN
Changes since 1.2:	+158 -57 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	NAME
2	root	1.3	cv - a fast gtk+ image viewer loosely modeled after XV
3	root	1.1
4			SYNOPSIS
5			cv [file...]
6
7	root	1.3	FEATURES
8			CV is supposed to work similar to the venerable XV image viewer, just
9			faster. Why faster?
10
11			* optimized directory scanning algorithm
12			The directory scanning in CV uses some tricks that - on most modern
13			filesystems - makes it possible to detect filetypes faster than
14			stat()'ing every file. This makes CV suitable for directories with
15			lots of files (10000+).
16
17			This algorithm is quite unprecise - it doesn't make a difference
18			between files, device nodes, symlinks and the like, and filetype
19			detection is done using the file extension only.
20
21			On the positive side, it is usually many orders of magnitude faster
22			than traditional scanning techniques (good for directories with
23			10000 or 100000+ files).
24
25			* queuing for all time-consuming background tasks
26			All tasks, such as unlinking files or generating thumbnails, that
27			can be done in the background will be done so - no waiting required,
28			even when changing directories.
29
30			* use of asynchronous I/O
31			CV tries to use asynchronous I/O whereever it makes sense, for
32			example while scanning directories, waiting for stat data, unlinking
33			files or generating thumbnails. This usually decreases scanning
34			times for large directories a bit (especially on RAID devices and
35			over NFS) and makes CV much more interactive.
36
37			* fast image loading
38			The time span between the user issuing a command and displaying the
39			new image should be as small as possible. CV uses optimized
40			(especially for JPEG) loading functions and sacrifices some quality
41			(e.g no gamma correction, although this might change) to achieve
42			this speed.
43
44			* fast thumbnail creation
45			Thumbnail creation uses both CPU and Disk-I/O. CV interleaves both,
46			so on modern CPUs, thumbnailing is usually limited by I/O speed.
47			Thumbnail creation for JPEGs has been specially optimized and can
48			even take advantage of multiple CPUs.
49
50			* minimum optical clutter
51			CV has no menus or other user interface elements that take up a lot
52			of screen space (or are useful for beginning users). The schnauzer
53			windows can also be somewhat crowded.
54
55			The point of an image viewer is viewing images, not a nice GUI. This
56			is similar to XV's behaviour.
57
58			* efficient (and hard to learn) user interface
59			CV uses key combinations. A lot. If you are an experienced XV user,
60			you will find most of these keys familiar. If not, CV might be hard
61			to use at first, but will be an efficient tool later.
62
63			* multi-window GUI
64			CV doesn't force you to use a specific layout, instead it relies on
65			your window manager, thus enabling you to chose whatever layout that
66			suits you most.
67
68			* i18n'ed filename handling throughout
69			As long as glib can recognize your filename encoding (either UTF-8
70			or locale-specific, depending on the setting of G_BROKEN_FILENAMES)
71			and you have the relevant fonts, CV will display your filenames
72			correctly.
73
74			* extensible through plug-ins
75			I have weird plug-ins that access remote databases to find a
76			directory. This is not likely to be of any use to other people.
77			Likewise, others might have weird requirements I cannot dream of.
78
79			* filename clustering
80			Among the standard plug-ins is a filename clustering plug-in, that
81			(in case of tens of thousands images in one directory) might be able
82			to cluster similar names together.
83
84	root	1.1	DESCRIPTION
85			THE IMAGE WINDOW
86			You can use the following keys in the image window:
87
88	root	1.3	q quit the program
89			< half the image size
90			> double the image size
91			, shrink the image by 10%
92			. enlarge the image by 10%
93			n reset to normal size
94			m maximize to screensize
95			M maximize to screensize, respecting image aspect
96			ctrl-m toggle maxpect-always mode
97			u uncrop
98			r set scaling mode to 'nearest' (fastest)
99			s set scaling mode to 'bilinear' (default)
100			shift-s set scaling mode to 'hyper' (slowest)
101			t rotate clockwise 90Â°
102			T rotate counterclockwiseÂ°
103			ctrl-v open a new visual schnauzer window for the current dir
104			ctrl-e run an editor ($CV_EDITOR or "gimp") on the current image
105			ctrl-p fire up the print fialog
106			escape cancel a crop action
107	root	1.1
108	root	1.2	And when playing movies, these additional keys are active:
109
110	root	1.3	left rewind by 10 seconds
111			right forward by 10 seconds
112			down rewind by 60 seconds
113			up forward by 60 seconds
114			pg_up rewind by 600 seconds
115			pg_down forward by 600 seconds
116			o toggle on-screen display
117			p pause/unpause
118			escape stop playing
119			9 turn volume down
120			0 turn volume up
121	root	1.2
122	root	1.3	Any other keys will be sent to the default schnauzer window, which can
123			be toggled on and off by right-clicking into the image window.
124	root	1.1
125	root	1.3	Left-clicking into the image window will let you crop the image (usually
126			to zoom into large images that CV scales down).
127	root	1.1
128			THE VISUAL SCHNAUZER
129			You can use the following keys in the schnauzer window:
130
131	root	1.3	ctrl-space,
132			space move to and display next image
133			ctrl-backspace,
134			backspace move to and display previous image
135			ctrl-return,
136			return display selected picture, or enter directory
137
138			cursor keys move selection
139			page-up move one page up
140			page-down move one page down
141			home move to first file
142			end move to last file
143
144			ctrl-a select all files
145			ctrl-shift-a select all files currently displayed in the schnauzer window
146			ctrl-d delete selected files WITHOUT ASKING AGAIN
147			ctrl-g force generation of thumbnais for the selected files
148			ctrl-s rescan current direcory or files updates/deletes etc.
149			ctrl-u update selected (or all) icons if neccessary
150			ctrl-l don't use, will become a plug-in eventually
151
152			^ go to parent directory (caret).
153
154			0-9,
155			a-z find the first filename beginning with this letter
156
157			Right-clicking into the schnauzer window displays a pop-up menu with
158			additional actions.
159
160			FILES
161			When starting, CV runs the .cvrc file in your $HOME directory as if it
162			were a perl script. in that, you will mostly load plug-ins.
163
164			Example:
165
166			system "fping -q -t 10 ether"
167			or require "/fs/cv/cvplugin.pl";
168
169			This will load a plug-in, but only if the machine ether is reachable
170			(supposedly the plug-in is networked in some way :).
171	root	1.1
172			ENVIRONMENT
173	root	1.2	CV_EDITOR
174			The program that gets executed when the user presses "CTRL-e" in the
175			Schnauzer or image window. The default is "gimp".
176
177	root	1.1	CV_PRINT_DESTINATION
178			The default (perl-style) destination to use in the print dialog.
179
180	root	1.2	CV_TRASHCAN
181			When set, must point to a directory where all files that are deleted
182			are moved to. If unset, files that are deleted are really being
183			deleted.
184
185	root	1.1	SECURITY CONSIDERATIONS
186	root	1.3	CV uses Pixbuf to load non-JPEG images. Pixbuf is not considered safe
187			for this purpose, though (from the gtk-2.2 release notes):
188	root	1.1
189			"While efforts have been made to make gdk-pixbuf robust against invalid
190			images, using gdk-pixbuf to load untrusted data is not recommended, due
191			to the likelyhood that there are additional problems where an invalid
192			image could cause gdk-pixbuf to crash or worse."
193
194			BUGS/TODO
195	root	1.3	Lots of functionality is missing.
196
197			Pixbuf doesn't always honor G_BROKEN_FILENAMES, so accessing files with
198			names incompatible with utf-8 might fail.
199	root	1.1
200			rotate on disk
201			lots of ui issues
202			save(?)
203			preferences
204
205			AUTHOR
206			Marc Lehmann <cv@plan9.de>.
207