| FvwmScript(1) | Fvwm Modules | FvwmScript(1) |
FvwmScript - module to build graphic user interface
FvwmScript must be spawned by Fvwm. It will not work from the command line.
FvwmScript is a module which allows you to build many graphical applications such as desktop accessories, button panel with pop up menus, modal dialogs... At the startup, FvwmScript reads the file which is specified on the command line. This file contains the script. This script is not included in the configuration file of Fvwm.
An FvwmScript script is fully controllable by using the keyboard. (Shift)-Tab circulates around the widgets, Return simulates a mouse click, the arrows move the cursor or change the values of the widget and Escape "cancels" for Menu and PopupMenu.
FvwmScript can be invoked by inserting the line `Module FvwmScript name_of_script' in the .fvwm2rc file. The file "name_of_script" can start with a slash, in which case, it's a fully qualified path, and the file is read. If "name_of_script" does not start with a slash, FvwmScript will look in a few different places. If the .fvwm2rc contained the command line `*FvwmScript: Path path_of_the_script_directory', FvwmScript will try that directory. If that doesn't work, FvwmScript tries the system configuration directory and the user configuration directory as described under the "Read" command in the fvwm man page.
The command to start FvwmScript can be placed on a line by itself, if FvwmScript is to be spawned during fvwm's initialization, or can be bound to a menu or mouse button or keystroke to invoke it later.
The following commands can be used in the config file (see fvwm(1), section MODULE COMMANDS for details). They are used only if the corresponding script commands are not used in the script.
FvwmScript uses a particular programming language. A script is composed of five parts. Heading contains general characteristics of the window and default properties for all widgets. The second part contains instructions whom are executed at the startup of the script. The third part contains periodic tasks which are executed every second. The fourth part contains instructions which are executed at exit. And the last part contains the description of widgets. A widget consists of eleven types of items: text labels, single-line text inputs, radio buttons, checkbox, push buttons, horizontal and vertical scrollbars, rectangles, pop up menus, swallowexecs and mini scrollbars.
The syntax is as follows:
This part contains instructions which will be executed at the startup. For example:
Init
Begin
Do "Exec cat tada.voc > /dev/dsp"
WarpPointer 1
Set $ToDo=Restart
End
These instructions are used to play a sound, move the pointer to widget 1 and to initialize $ToDo to "Restart" at every startup.
This part of the script contains instructions that are executed every second. For example:
PeriodicTasks
Begin
If (RemainderOfDiv (GetTime) 10)==0 Then
Do {Exec xcalc}
End
This example shows how to launch xcalc every 10 seconds.
This part of the script contains instructions that are executed when the script exits (after the Quit instruction or if you close the window with the Close, Delete or Destroy fvwm command). For Example
QuitFunc
Begin
Do {Echo bye, bye}
End
Be aware that if you used the KillModule fvwm command to close the script, some instructions or functions which rely on the existence of a communication link between the script and fvwm will not be executed (for example the Do command). To smoothly kill a script with an fvwm command see the COMMANDS section.
The second part of the script contains the description for every widget in the script. Each widget description has two parts. The first part describes initial properties, the second part contains instructions that are executed when the widget receives messages. All widgets can send and receive messages. All messages are identified by a number. The message "UserAction" is sent to a widget when the user operates the widget. The syntax for the first part is:
Widget id # A number between 1 and 999 inclusive Property
Type string
Size width height
Position x y
Title { string }
Value int
MaxValue int
MinValue int
Font string
ForeColor { color }
BackColor { color }
HilightColor { color }
ShadowColor { color }
Colorset int
Flags flagsOpt
The flagsOpt option to Flags is a space separated list containing one or more of the keywords Hidden, NoReliefString, NoFocus, Left / Center / Right. Hidden is used to specify if the widget is hidden at startup. NoReliefString specifies if strings are drawn with relief or not. NoFocus specifies if the widget can get the keyboard focus or not. By default all widgets take focus, except Rectangle, HDipstick and VDipstick which cannot. Moreover, the NoFocus widgets are skipped when you circulate around the widgets with the (Shift-)Tab short cut. Left / Center / Right specifies the text position. These apply only to ItemDraw, List, Menu, PopupMenu and PushButton. The default is Center for ItemDraw and PushButton and Left for the other widgets.
LocaleTitle can be used in place of Title, for using the locale catalog(s) defined with UseGettext.
The position of every widget must be specified.
The syntax for the second part is:
Main
Case message of
SingleClic:
Begin
# list of instructions which will be
# executed when widget receives
# message "SingleClic". This message is
# generated by the user.
End
1 :
Begin
# list of instructions which will be
# executed when widget receives
# message 1
End
End
There is fifteen types of widgets.
Title: title of the check box.
Value: if Value is equal to 1, the box is checked else it is not.
The Size property is ignored.
Value: specify the current value of the dipstick.
MinValue: specify the minimum value of the dipstick.
MaxValue: specify the maximum value of the dipstick.
A minimum size of 30x11 is imposed.
Value: position of the thumb.
MaxValue: upper limit of Value.
MinValue: lower limit of Value.
The height property is ignored and a minimum width is imposed. The width should be at least the range plus 37 if all values are to be selectable e.g. a min of 0 and max of 10 has a range of 11 and therefore should have a minimum width of 48.
Title: string to display.
Icon: icon to display.
MaxValue: x coordinate of the cursor.
MinValue: y coordinate of the cursor.
The size is made large enough to contain the title and/or the icon.
Value: specify which option is selected.
MinValue: First visible option.
Title: title contains options displayed in the list. The syntax is the following: {Option 1|Option 2|...|Option N}. All menus are displayed at the top of window.
A minimum height of three items is imposed and the width is made to be at least 108.
Value: specify which option is selected.
Title: title contains options displayed in the menu. The syntax is the following: {Option 1|Option 2|...|Option N}.
Value: position of the thumb.
MaxValue: upper limit of Value.
MinValue: lower limit of Value.
The size is set to 19x34.
Value: specify what option is selected.
Title: the title has the following syntax: {Option 1|Option 2|...|Option N}."Option 1|Option 2|...|Option N" is the pop up menu which is displayed when pressing mouse button.
The size property is ignored.
Title: this string has the following syntax {Title of the button|Option 1|Option 2|Option3|...|Option N}. "Option 1|Option 2|...|Option N" is the pop up menu which is displayed when pressing the right button.
Icon: icon to display.
The button is made large enough to fit the icon and or label.
Title: title of the radio button.
Value: if Value is equal to 1, the box is checked else it is not.
The size property is ignored
Title: specify the window name which be captured and displayed in the script window.
SwallowExec: specify the command line to execute to spawn the process. Modules can also be swallowed.
Value: specify the looking of the border. Possible value: -1, 0, 1.
The size is made to be at least 30x30
Title: content of text field.
Value: position of the insert point.
MinValue: position of the end of the selection.
MaxValue: first visible character of the title
The height property is ignored, the width is made to be at least 40 pixels wider than the initial contents.
Value: specify the current value of the dipstick.
MinValue: specify the minimum value of the dipstick.
MaxValue: specify the maximum value of the dipstick.
The size is made to be at least 11x30.
Value: position of the thumb.
MaxValue: upper limit of Value.
MinValue: lower limit of Value.
The width property is ignored and a minimum height is imposed. The height should be at least the range plus 37 if all values are to be selectable e.g. a min of 0 and max of 10 has a range of 11 and therefore should have a minimum height of 48.
Here is the description of all instructions.
SendSignal id sig
and sets the "last string" to the concatenation of str1, str2... (see the LastString function). The Keyname and Modifiers fields are defined as in the fvwm Key command.
Most of commands use arguments. There are two kinds of arguments: numbers and strings. A numerical argument is a value which is between -32000 and +32000. A string is always surrounded with braces. Variables always begin with the character "$" and can contain both numbers and strings.
All functions use arguments. Functions can return both a string and a number. The syntax is:
(function argument1 argument2 etc)
Here is the complete list of arguments:
X1S1X2S2X3S3...SnXn
where the Xn are numbers containing four decimal digits and where Sn are
strings of length exactly Xn. The returned value is the string
Sint. If int is out of range (e.g., >n) the returned
value is the empty string. If str is not of the specified form, the
return value is unpredictable (but empty in the average). This function is
useful to handle strings returned by the SendMsgAndGet function.
There are three kinds of conditional loops. The instruction "If-Then-Else" has the following syntax:
If $ToDo=={Open xcalc} Then
Do {Exec xcalc &} # List of instructions
Else
Begin
Do {Exec killall xcalc &} # List of instructions
Do {Exec echo xcalc killed > /dev/console}
End
The second part "Else-Begin-End" is optional. If the loop contains only one instruction, Begin and End can be omitted. The instruction "While-Do" has the following syntax:
While $i<5 Do Begin
Set $i=(Add i 1) # List of instructions End
Two strings can be compared with "==" and two numbers can be compared with "<", "<=", "==", ">=", ">". The loop "For-Do-Begin-End" has the following syntax:
For $i=1 To 20 Do Begin
Do {Exec xcalc &} # List of instructions End
The following fvwm command may be executed at any time
SendToModule ScriptName SendString id sig str
it sends to any module with alias or name which matches ScriptName the string
SendString id sig str
When an FvwmScript receives such a message it sends to the Widget id the signal numbered sig and the string str can be obtained with the LastString function. Let us give an example. Say that you have a script MyScript with the widget:
Widget 50 PropertyThen the command
Type PushButton
Title {Quit}
... Main Case message of
SingleClic:
Begin
Quit
End
1 :
Begin
Set $str = (LastString)
If $str == {Quit} Then
Quit
Else
ChangeTitle 33 $str
End End
SendToModule MyScript SendString 50 1 strforces MyScript to exit if str is equal to "Quit" and if not it changes the title of Widget 33 to str.
This command can be used to change the window title
SendToModule ScriptName ChangeWindowTitle newTitle [oldTitle]
it causes that any module with alias or name which matches ScriptName changes its associated window title to newTitle. The optional argument oldTitle makes sense when there are several instances of the same script. It permits one to avoid changing the name of all these instances by specifying the name of the window associated to the target script (see the example below).
+ I Module FvwmScript FvwmStorageSend "/dev/hda6" + I Wait FvwmStorageSend + I SendToModule FvwmStorageSend ChangeWindowTitle HDA6 + I Module FvwmScript FvwmStorageSend "/dev/hda1" + I Wait FvwmStorageSend + I SendToModule FvwmStorageSend ChangeWindowTitle HDA1 FvwmStorageSend
Without the FvwmStorageSend argument in the last case, the SendToModule command would have changed to HDA1 the name of both instances of FvwmStorageSend.
You will find examples of scripts in the fvwm configuration directory.
FvwmScript-BellSetup, FvwmScript-KeyboardSetup, FvwmScript-PointerSetup and FvwmScript-ScreenSetup are a set of scripts that modify X settings. These scripts save preferences into a file named ~/.xinit-fvwmrc (If you want to use another file name, give it as the first argument of the script). If you want to load these preferences at every startup, you have to include the line ".xinit-fvwmrc" in your .xinitrc (or .xsession) file before starting fvwm.
FvwmScript-BaseConfig modifies fvwm focus and paging mouse policy, window placement, opacity and other features of the move and resize commands, snap attraction and shading animation. This script saves preferences into a file named .FvwmBaseConfig in the user's data directory (i.e., $HOME/.fvwm or $FVWM_USERDIR if set). If you want to load these preferences at every startup you must add the line "Read .FvwmBaseConfig" in your fvwm configuration file. If you want to use another file name, give it as the first argument of the script. When you click on Ok or Apply an fvwm function that you may define named BaseConfigOkFunc or BaseConfigApplyFunc is called. This allows for reloading specific application styles that the script has destroyed (e.g., AddToFunc BaseConfigOkFunc I Read MyAppStyle).
FvwmScript-Buttons is a buttons panel which can replace FvwmButtons (this script supports popup menus and requires xload, xclock, FvwmPager, TkDesk). FvwmScript-Colorset allows you to edit your colorset. FvwmScript-Date allows you to set date and time. FvwmScript-FileBrowser is a file browser used by the other scripts. FvwmScript-Find is an elementary front-end to find. FvwmScript-Quit allows one to quit fvwm, restart fvwm or some other window manager, or shut down and reboot the computer. FvwmScript-ScreenDump is a screen dumper. FvwmScript-WidgetDemo is a pure example script. See the next section for FvwmScript-ComExample.
FvwmScript is a weak (but simple) programming language. If you need to deal with a lot of data and/or you need to use complex algorithms you should use an external program (in perl for example) and "send" the desired information to your FvwmScript script. The first approach is to use the GetOutput function. This is simple but you should rerun your external program each time you need information from it (and this may cause performances problems). The second approach is to use the SendMsgAndGet function which extends FvwmScript by using any programming language which can deal with named pipes (fifos). We describe this solution in this section. (A third approach is to use fvwm-themes-com from the fvwm-themes package, but in fact the SendMsgAndGet method is an implementation of fvwm-themes-com inside FvwmScript and this gives better performance).
Basically, you start an "external" program (the program for short) from your FvwmScript script (the script for short). This program runs in the background and you use the SendMsgAndGet function in your script to ask questions or to give instructions to the program. The program must strictly respect a certain communication protocol. First of all there is an identifier comId for the communication, it should contain the process id of the script for a good implementation of the protocol (use the GetPid function and pass the comId via an option to the program). The protocol uses two fifos, in the fvwm user directory, named: .tmp-com-in-comId and .tmp-com-out-comId. The program should create and listen on the .tmp-com-in-comId fifo. Then, when FvwmScript executes a function of the form:
Set $answer = (SendMsgAndGet {comId} {cmd} bool)
FvwmScript writes the cmd on this fifo. This way the program can read the cmd and can execute the appropriate action (it should remove the in fifo to support multi-communications). If bool is 0, FvwmScript does not wait for an answer from the program and return 1 if the previous actions succeed and 0 if they failed (then the program should "go back" to the in fifo). If bool is 1, then FvwmScript waits (20 sec) for an answer from the program and in turn returns the answer to the script (note that bool is not passed to the program as it must know which commands need an answer). To answer, the program creates the .tmp-com-out-comId fifo and writes the answer on it. The program should wait until FvwmScript reads the answer and then it should remove the out fifo and go back to the in fifo. The answer should consist of one line of no more than 32000 characters (take a look at the Parse function to handle multiple lines as one line).
A simple way to understand this protocol and to write scripts and programs that use it is to take a look at the (not useful) example FvwmScript-ComExample and fvwm-script-ComExample.pl (that can found in the fvwm data directory). Moreover, this implementation of the protocol solves questions as: What to do if the script exits for a bad reason? What to do if the program exits for a bad reason? ...etc.
FvwmScript crashes if widgets are accessed that have not been defined.
Frederic Cordier (cordie97@cui.unige.ch or f-cord96@univ-lyon1.fr).
Eddy J. Gurney (eddy@gizmo.aa.ans.net).
| 19 October 2022 (2.7.0) | 3rd Berkeley Distribution |