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NAME
lxb - lxb X widget
SYNOPSIS
lxb
DESCRIPTION
lxb is an X/Motif interactive graphical user interface builder. With
it you can build a GUI made up of Motif widgets instantiated from a
pallet, move and resize them, edit their resources, and move about in
the widget heirarchy. Once the GUI is built, pressing a button will
produce the required C source files to build the GUI, and an X
resource file and Makefile.
FEATURES
There are 4 lxb windows:
1. The main lxb window
2. The resource editor
3. The widget pallet
4. The application GUI being built
Screen shots and descriptions can be found on the lxb web page.
"http://www.tc.umn.edu/nlhome/g257/parki005/lxb/lxb.html"
1) Menubar
Files Pulldown:
* New Button: Begin a new GUI
* Open Button: Opens an existing lxb save file. (See below)
* Save Button: Saves the current GUI in the current save file.
* Save As.. Button: Saves the current GUI in another lxb save file.
* Quit Button: Exits lxb.
Edit Pulldown:
* Delete Widget Button: Deletes the selected widget.
Options Pulldown:
* Play Mode Button: Creates GUI just as if the user had compiled
the
generated C code and run the program. The GUI can then be tested
and
checked as to how it will really function once made.
* Code Button: Produces the C source code, header files, X defaults
file,
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and Makefile for the GUI application.
* Application Name.. Button: displays a popup that allows the user
to
change the name of the application GUI being built.
Diagnostics Pulldown
* Dump Widget Tree Button: Lists the widgets in the application.
* Selected Widget Resources Button: Lists resources of the selected
widget.
2) Widget Heirarchy Area:
Displays a window that uses the Xaw widgets Porthole, Panner, and Tree
along with Motif pushbuttons to display the parent/child relationship
of the widgets in the created GUI in a tree structure. The nodes in
the tree are all named according to the widgets in the GUI. Clicking
on a node in the tree in this window will cause the corresponding
widget in the GUI application to be "selected". The "selected" widget
is the one that can be resized, moved, and have it's resources edited.
Usually, the selected widget will have a black border around it in the
GUI being built. (There are a few quirks in Motif that I have not made
work arounds for yet so once in while this may not happen). The
selected widget WILL be indicated in the Widget Heirarchy Display
window by inverting the colors on the node with it's name.
The other way of selecting a widget is to click on it with MB1 in the
GUI itself.
RESOURCE EDITOR
The top area lists some data on the selected widget. Here you can
change the widget's name and set it's variable in the code to local or
global.
The next area down is a List of all resources associated with the
selected widget. Clicking once on one of the entries in this list will
retrieve the resource value and place it in the text widget that is
directly beneath it. (Providing that the work has been done in lxb to
handle that resource).
If the resource value has several options, such as a color, or the
enumerated types, all possible values will appear in the small List
box directly beneath the text input field.
Clicking on any selection in the option box places it in the text
input box.
A value may also be entered with the keyboard into the text input
field, and of course this method must be used for normal resources,
like width and height. Pressing the OK button or Return key will will
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result in lxb attempting to set whatever is in the text input field as
the value for resource selected in the top most List box in the
widget.
WIDGET PALLET
This will appear to the left of the main lxb window. On it are the
Motif widget names in icon-like pushbuttons. Pressing on one will, if
it is legal, result in that widget being instantiated as a child of
the current selected widget.
APPLICATION GUI
This will appear below the main lxb GUI area, but can be moved and
resized and placed where ever you wish. This is the GUI application
the user is building, and the canvas from where the user will work.
NAVIGATION AMONGST THE GUI'S WIDGETS
When the pointer is in the GUI application window and mouse buttons
are pressed the results are described below.
* MB1: Selects widgets. When the pointer is in the aplication
window and
over the the widget and this button is pressed and released, the
widget
becomes the selected widget.
* MB1: Moves widgets. If MB1 is pressed and held, and the mouse
moved,
the widget will be dragged about in the application area. But see
the
note below on container widgets.
* MB2: Resizes a widget. If it is the selected widget. Press and
hold MB2
with the pointer in the selected widget, and it will drag-resize
by
it's bottom right corner.
The other way of selecting a widget is to click on the node in the
tree of the Widget Heirarchy Display Window with the same name using
MB1. Note that for this is the only way to select certain of the
widget children in Menus.
Selecting a widget results in it's corresponding node in the tree in
the Widget Heirarchy Display Window to have it's colors inverted, and
the widget in the application GUI to have a black border appear around
it (in most cases; once in a great while this does not happen.)
SPECIAL CASES
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* MENUBARS
Menus in Motif are somewhat obtuse. lxb is not at the point where
it
makes building menus possible without knowing something about
them.
The first widget instantatiated must be the MenuBar. It's parent
can be
any container widget.
The second widget instantiated as the child of the MenuBar is the
Cascade Button. When the Cascade Button is created, so is a
MenuShell
and Pulldown, visable in the Widget Heirarchy Display window but
not in
the GUI application, the MenuShell as a child of the MenuBar and
the
pulldown as a child of the MenuShell. Welcome to Motif.
After the Cascade Button has been created, all other widgets
desired
can be added - PushButtons, ToggleButtons, Seperators, etc, to
make the
pulldown menu complete.
NOTE: The parent, however, of these additional widgets is the
PULLDOWN,
not the Cascade Button.
Other Cascade Buttons can be created as children of the MenuBar
and
similar hierarchies of widgets be created to build up a complete
MenuBar. However, Cascading Menus probably will not work, and I
would
not use them. (Cascading menus are those where Cascade Buttons
are
themselves children of other Cascade Buttons, so the you get a
multi-tiered menu cascading to the right). They are not good user
interface design, either, in MY honest opinion; it's better to
use only
one layer of pulldown widgets from a Cascade button and if
further
selection is required put up a popup for the user. Note, IMHO
only.
MenuShells and Pulldowns cannot be edited or deleted. One must
delete
the associated Cascade Button and delete the entire hierarchy.
The above rules will be inforced on you the user. Watch stdout
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for
messages.
Also, Menubars do not work real well in "Play Mode". But they
come out
OK when the application is compiled and run.
* SCROLLED WINDOWS:
Use ScList and ScText to make ScrolledText and ScrolledList
widgets,
instead of trying to make the widget heirarchy using the widget
pallet.
This is this way because of Motif. Other widget heirarchies can
be
created OK, like a Scrolled Window with a Drawing Area as a
child.
You will notice scrollbars and clip window widgets being created
automagically at times and displayed on the Widget Hierarchy
Display
Window. These widgets cannot be deleted without deleting the
parent
Scrolled Window, although most of them can have their resources
edited.
I wouldn't reccommend editing their resources, however, except
for
maybe their background and foreground colors.
No ClipWindow widget is created for scrolled text or scrolled
lists.
No horizontal scrollbar is created for a scrolled list.
To resize an ScList (scrolled list) resize the List child, then
re-select up in the heirarchy and the Scrolled Window parent will
resize by itself properly.
In order to get a resize of a ScrolledList or ScText a drag with
mb2
held down on the parent ScrolledWindow is not enough. The width
and
height of the child widget - the text or the list widget - must
be
either set with mb2 or the width and height resources set
explicitly
with the resource editor.
* SCROLL BARS:
The XmNvalue resource for the XmScrollBar widget is of type int.
The XmNvalue resource for the XmText widget is of type String.
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Currently, lxb can only have one datatype for each resource type,
and
XmText/String won. Getting or setting the resouce value for
XmNvalue on
a Scrollbar with the resource editor will show garbage on the
screen on
a get, and incorrect syntax on generated code for a set. So don't
change this resouce with lxb.
* Selecting Container Widgets
Such as forms, rowcolumns; currently may be difficult to select,
or
impossible, depending on the border thickness and similar
resources
without using the Widget Display Window. And of course this does
not
help if you are trying to move or resize the container widgets.
Try
clicking with the pointer on the very edge of the container
widget. Of
course, you can always move and resize by editing the XmNx, XmNy,
XmNwidth, XmNheight resources after selecting using the Widget
Display
Window.
* Forms
The XmForm widget is included in the widgets that may be
instantiated
and resources edited with lxb. However, you may observe quite
strange
behaviour in regard to this widget off and on. It is most likely
due to
the resources you have set for it. You may want to play with the
XmNresizePolicy resource for the from to see if you get better
results.
Beware circular contraints. They don't work.
MORE INFORMATION
For more information see
"http://www.tc.umn.edu/nlhome/g257/parki005/lxb/lxb.html"
PROGRAM AUTHOR
Bruce Parkin <bruce.parkin-1@umn.edu>
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MAN PAGE
Mehdi Lavasani <lavasani@csc.liv.ac.uk>
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