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Text File | 1995-03-15 | 14KB | 348 lines

NAME xdaliclock - melting digital clock SYNOPSIS xdaliclock [-toolkitoption ...] [-option ...] DESCRIPTION The xdaliclock program displays a digital clock; when a digit changes, it ``melts'' into its new shape. This program was inspired by the Alto and Macintosh pro- grams of the same name, written by Steve Capps in 1983 or 1984. OPTIONS xdaliclock accepts all of the standard toolkit options, and also accepts the following options: -help Print a brief summary of the allowed options on the standard error output. -12 Use a twelve hour clock. -24 Use a twenty-four hour clock. -seconds Update every second. -noseconds Update once per minute; don't display seconds at all. -cycle Do color-cycling. -nocycle Don't do color-cycling. -visual visual Specify which visual to use. Legal values are: best Use the visual which supports the most writable color cells; this is the default. default Use the screen's default visual (the visual of the root window.) This is not necessarily the most colorful visual, which is why it is not the default. class One of StaticGray, StaticColor, TrueColor, GrayScale, PseudoColor, or DirectColor. Selects the deepest visual of the given class. number A number (decimal or hex) is interpreted X Version 11 15-May-94 1 as a visual id number, as reported by the xdpyinfo(1) program; in this way you can select a shallower visual if desired. -shape Use the Shape Extension, if it's available, to make the window background be transparent. This doesn't interact terribly well with the twm or tvtwm window managers, unless they have been configured to not put a titlebar on the xdaliclock window. If this isn't specified in your .twmrc or .tvtwmrc file, then the window will flicker con- stantly, as the window manager tries to add and remove the titlebar ten times each second. Also, this turns most X servers into huge cycle hogs. This is probably because of inefficient implementations of the Shape extension. -noshape Don't use the Shape Extension. -memory low Use high-bandwidth, low-memory mode. If you have a very fast connection between the machine this program is running on and the X server it is dis- playing on, then xdaliclock can work correctly by simply making the drawing requests it needs when it needs them. This is the elegant method. How- ever, the amount of data necessary to animate the display ends up being a bit over 10 kilobytes worth of X Protocol per second. On a fast machine with a local display, or over a fast network, that's almost negligible, but (for example) an NCD X Terminal at 38.4 kilobaud can't keep up. That is the reason for: -memory medium Use high-memory, low-bandwidth mode. In this mode, xdaliclock precomputes most of the frames that it will ever need. This is the sleazy copout method. The bandwidth requirements are drasti- cally reduced, because instead of telling the server what bits to draw where, it merely tells it what pixmaps to copy into the window. Aside from the fact that I consider this to be cheating, the only downside of this method is that those pixmaps (about 170 of them, each the size of one charac- ter) are consuming server-memory. This probably isn't a very big deal, unless you're using an exceptionally large font. -memory high With memory set to high, the cache is twice as X Version 11 15-May-94 2 large (the n -> n+2 transitions are cached as well as the n -> n+1 ones). Even with memory set to medium, this program can seem sluggish when using the builtin font over a very slow connection to the display server. -font fontname Specifies the X font to use; xdaliclock can cor- rectly animate any font that contains all the dig- its plus colon and slash, and in which the letters aren't excessively curly. The xdaliclock program contains a pair of builtin bitmapped fonts, which are larger and more attrac- tive than the standard X fonts. One of these fonts will be used if the -font option is given one of the fontnames BUILTIN or BUILTIN2. -builtin This is the same as specifying -font BUILTIN. -builtin2 This is the same as specifying -font BUILTIN2. -fullscreen Make the window take up the whole screen. When -fullscreen is specified, the displayed time will wander around a little, to prevent any pixels from being on continuously and causing phosphor burn- in. -root Display the clock on the root window instead of in its own window. This makes the digits wander around too. The following standard X Toolkit command line arguments are commonly used with xdaliclock: -display host:dpy This option specifies the X server to contact. -geometry geometry This option specifies the prefered size and posi- tion of the clock window. -bg color This option specifies the color to use for the background of the window. The default is ``white.'' -fg color This option specifies the color to use for the foreground of the window. The default is ``black.'' X Version 11 15-May-94 3 -bd color This option specifies the color to use for the border of the window. The default is the same as the foreground color. -rv This option indicates that reverse video should be simulated by swapping the foreground and back- ground colors. -bw number This option specifies the width in pixels of the border surrounding the window. -xrm resourcestring This option specifies a resource string to be used. COMMANDS Clicking and holding any mouse button in the xdaliclock window will cause it to display the date while the button is held. Typing ``space'' at the xdaliclock window will toggle between a twelve hour and twenty-four hour display. Typing ``q'' or ``C-c'' at the window quits. If the xdaliclock window is iconified or otherwise unmapped, it will go to sleep until it is mapped again. X DEFAULTS xdaliclock understands all of the core resource names and classes as well as: seconds (class Seconds) Whether to display seconds. If true, this is the same as the -seconds command line argument; if false, this is the same as -noseconds. cycle (class Cycle) Whether to do color cycling. If true, this is the same as the -cycle command line argument; if false, this is the same as -nocycle. shape (class Shape) Whether to use the Shape Extension, if available. If true, this is the same as the -shape command line argument; if false, this is the same as -noshape. memory (class Memory) This must be high, medium, or low, the same as the -memory command-line option. X Version 11 15-May-94 4 font (class Font) The same as the -font command line option: the font to melt. If this is the string BUILTIN, then the large builtin font is used. If this is the string BUILTIN2, then the even larger builtin font is used. Otherwise, this must be the name of a valid X font. mode (class Mode) Whether to display 12-hour or 24-hour time. If 12, this is the same as the -12 command line argu- ment; if 24, this is the same as -24. datemode (class DateMode) Specifies how the date should be printed when a mouse button is held down. This may be one of the strings mm/dd/yy, dd/mm/yy, yy/mm/dd, yy/dd/mm, mm/yy/dd, or dd/yy/mm. The default is mm/dd/yy. If seconds are not being displayed, then only the first four digits will ever be displayed (mm/dd instead of mm/dd/yy, for example.) fullScreen (class FullScreen) The same as the -fullscreen command-line option. root (class Root) The same as the -root command-line option. visualID (class VisualID) The same as the -visual command-line option. ENVIRONMENT DISPLAY to get the default host and display number. XENVIRONMENT to get the name of a resource file that overrides the global resources stored in the RESOURCE_MANAGER prop- erty. TZ to get the current time zone. If you want to force the clock to display some other time zone, set this variable before starting it. For example: $ TZ=GMT0 xdaliclock % ( setenv TZ PST8PDT ; xdaliclock ) You may notice that the format of the TZ variable (which is used by the C library ctime(3) and local- time(3) routines) is not actually documented anywhere. The fourth character (the digit) is the only thing that really matters: it is the offset in hours from GMT. The first three characters are ignored. The last three characters are used to flag daylight X Version 11 15-May-94 5 savings time: their presence effectively adds 1 to the zone offset. (I am not making this up...) SEE ALSO X(1), xrdb(1), xlsfonts(1), xclock(1), dclock(1), oclock(1), tclock(1), xscreensaver(1) BUGS Other system load will sometimes cause the second-display to increment by more than one second at a time, in order to remain synchronized to the current time. The -memory option is disgusting and shouldn't be neces- sary, but I'm not clever enough to eliminate it. It has been said that hacking graphics in X is like finding sqrt(pi) with roman numerals. When using a small font (less than 48x56 or so) it's pos- sible that shipping a bitmap to the server would be more efficient than sending a DrawSegments request (since the endpoints are specified using 16 bits each, when all that we really need is 6 or 7 bits.) Support for the Shared Memory Extension would be a good thing. It should display the day of the week somewhere. The color cycling should be less predictable; it should vary saturation and intensity as well, and should be more careful that foreground and background contrast well. Should have a -analog mode (maybe someday...) COPYRIGHT Copyright (C) 1991, 1992, 1993, 1994 by Jamie Zawinski. Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. No representations are made about the suitability of this software for any purpose. It is pro- vided "as is" without express or implied warranty. AUTHOR Jamie Zawinski <jwz@lucid.com>, 18-sep-91. Please let me know if you find any bugs or make any improvements. Thanks to Ephraim Vishniac <ephraim@think.com> for explaining the format of the bitmap resources in the Mac- intosh version of this, so that I could snarf them for the X Version 11 15-May-94 6 -builtin fonts. And thanks to Steve Capps for the really great idea. X Version 11 15-May-94 7