[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
     ctrl-sift-m  toggle using current image size as max image size
     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-c       clone the current image window
     ctrl-e       run an editor ($CV_EDITOR or "gimp") on the current image
     ctrl-p       fire up the print dialog
     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
    Any image-loading action in a schnauzer window acts on the
    "last-recently-activated" imagewindow, which currently is simply the
    last image window that received a keypress.

    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.

   SELECTION
    You can select entries in the Schnauzer in a variety of ways:

    Keyboard
        Moving the cursor with the keyboard will first deselect all files
        and then select the file you moved to.

    Clicking
        Clicking on an entry will select the one you clicked and deselect
        all others.

    Shift-Clicking
        Shift-clicking will toggle the selection on the entry under the
        mouse.

    Dragging
        Dragging will select all entries between the one selected when
        pushing the button and the one selected when releasing the button.
        If you move above or below the schnauzer area while drag-selecting,
        the schnauzer will move up/down one row twice per second. In
        addition, horizontal mouse movement acts as a kind of invisible
        horizontal scrollbar.

    Hint: double-click works while click-selecting
        You can double-click any image while click-selecting to display it
        without stopping the selection process. This will act as if you
        normally double-clicked the image to display it, and will toggle the
        selection twice, resulting in no change.

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:	1.4
Committed:	Fri Oct 28 13:53:16 2005 UTC (18 years, 6 months ago) by root
Branch:	MAIN
CVS Tags:	rel-1_1
Changes since 1.3:	+36 -1 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	root	1.4	ctrl-sift-m toggle using current image size as max image size
98	root	1.3	u uncrop
99			r set scaling mode to 'nearest' (fastest)
100			s set scaling mode to 'bilinear' (default)
101			shift-s set scaling mode to 'hyper' (slowest)
102			t rotate clockwise 90Â°
103			T rotate counterclockwiseÂ°
104			ctrl-v open a new visual schnauzer window for the current dir
105	root	1.4	ctrl-c clone the current image window
106	root	1.3	ctrl-e run an editor ($CV_EDITOR or "gimp") on the current image
107	root	1.4	ctrl-p fire up the print dialog
108	root	1.3	escape cancel a crop action
109	root	1.1
110	root	1.2	And when playing movies, these additional keys are active:
111
112	root	1.3	left rewind by 10 seconds
113			right forward by 10 seconds
114			down rewind by 60 seconds
115			up forward by 60 seconds
116			pg_up rewind by 600 seconds
117			pg_down forward by 600 seconds
118			o toggle on-screen display
119			p pause/unpause
120			escape stop playing
121			9 turn volume down
122			0 turn volume up
123	root	1.2
124	root	1.3	Any other keys will be sent to the default schnauzer window, which can
125			be toggled on and off by right-clicking into the image window.
126	root	1.1
127	root	1.3	Left-clicking into the image window will let you crop the image (usually
128			to zoom into large images that CV scales down).
129	root	1.1
130			THE VISUAL SCHNAUZER
131	root	1.4	Any image-loading action in a schnauzer window acts on the
132			"last-recently-activated" imagewindow, which currently is simply the
133			last image window that received a keypress.
134
135	root	1.1	You can use the following keys in the schnauzer window:
136
137	root	1.3	ctrl-space,
138			space move to and display next image
139			ctrl-backspace,
140			backspace move to and display previous image
141			ctrl-return,
142			return display selected picture, or enter directory
143
144			cursor keys move selection
145			page-up move one page up
146			page-down move one page down
147			home move to first file
148			end move to last file
149
150			ctrl-a select all files
151			ctrl-shift-a select all files currently displayed in the schnauzer window
152			ctrl-d delete selected files WITHOUT ASKING AGAIN
153			ctrl-g force generation of thumbnais for the selected files
154			ctrl-s rescan current direcory or files updates/deletes etc.
155			ctrl-u update selected (or all) icons if neccessary
156			ctrl-l don't use, will become a plug-in eventually
157
158			^ go to parent directory (caret).
159
160			0-9,
161			a-z find the first filename beginning with this letter
162
163			Right-clicking into the schnauzer window displays a pop-up menu with
164			additional actions.
165
166	root	1.4	SELECTION
167			You can select entries in the Schnauzer in a variety of ways:
168
169			Keyboard
170			Moving the cursor with the keyboard will first deselect all files
171			and then select the file you moved to.
172
173			Clicking
174			Clicking on an entry will select the one you clicked and deselect
175			all others.
176
177			Shift-Clicking
178			Shift-clicking will toggle the selection on the entry under the
179			mouse.
180
181			Dragging
182			Dragging will select all entries between the one selected when
183			pushing the button and the one selected when releasing the button.
184			If you move above or below the schnauzer area while drag-selecting,
185			the schnauzer will move up/down one row twice per second. In
186			addition, horizontal mouse movement acts as a kind of invisible
187			horizontal scrollbar.
188
189			Hint: double-click works while click-selecting
190			You can double-click any image while click-selecting to display it
191			without stopping the selection process. This will act as if you
192			normally double-clicked the image to display it, and will toggle the
193			selection twice, resulting in no change.
194
195	root	1.3	FILES
196			When starting, CV runs the .cvrc file in your $HOME directory as if it
197			were a perl script. in that, you will mostly load plug-ins.
198
199			Example:
200
201			system "fping -q -t 10 ether"
202			or require "/fs/cv/cvplugin.pl";
203
204			This will load a plug-in, but only if the machine ether is reachable
205			(supposedly the plug-in is networked in some way :).
206	root	1.1
207			ENVIRONMENT
208	root	1.2	CV_EDITOR
209			The program that gets executed when the user presses "CTRL-e" in the
210			Schnauzer or image window. The default is "gimp".
211
212	root	1.1	CV_PRINT_DESTINATION
213			The default (perl-style) destination to use in the print dialog.
214
215	root	1.2	CV_TRASHCAN
216			When set, must point to a directory where all files that are deleted
217			are moved to. If unset, files that are deleted are really being
218			deleted.
219
220	root	1.1	SECURITY CONSIDERATIONS
221	root	1.3	CV uses Pixbuf to load non-JPEG images. Pixbuf is not considered safe
222			for this purpose, though (from the gtk-2.2 release notes):
223	root	1.1
224			"While efforts have been made to make gdk-pixbuf robust against invalid
225			images, using gdk-pixbuf to load untrusted data is not recommended, due
226			to the likelyhood that there are additional problems where an invalid
227			image could cause gdk-pixbuf to crash or worse."
228
229			BUGS/TODO
230	root	1.3	Lots of functionality is missing.
231
232			Pixbuf doesn't always honor G_BROKEN_FILENAMES, so accessing files with
233			names incompatible with utf-8 might fail.
234	root	1.1
235			rotate on disk
236			lots of ui issues
237			save(?)
238			preferences
239
240			AUTHOR
241			Marc Lehmann <cv@plan9.de>.
242