The dialog library attempts to provide a fairly simplistic set of
fixed-presentation menus, input boxes, gauges, file requestors and
other general purpose GUI (a bit of a stretch, since it uses
ncurses) objects.
Since the library also had its roots in a
shell-script writers utility (see the
dialog(1)
command), the
early API was somewhat primitively based on strings being passed in or
out and parsed.
This API was later extended to take either the
original arguments or arrays of
dialogMenuItem
structures,
giving the user much more control over the internal behavior of each
control.
The
dialogMenuItem
structure internals are public:
typedef struct _dmenu_item {
char *prompt;
char *title;
int (*checked)(struct _dmenu_item *self);
int (*fire)(struct _dmenu_item *self);
int (*selected)(struct _dmenu_item *self, int is_selected);
void *data;
char lbra, mark, rbra;
long aux;
} dialogMenuItem;
The
prompt
and
title
strings are pretty much self-explanatory,
and the
checked
and
fire
function pointers provide optional
display and action hooks (the
data
variable being available for
the convenience of those hooks) when more tightly coupled feedback between
a menu object and user code is required.
The
selected
hook also
allows you to verify whether or not a given item is selected (the cursor is
over it) for implementing pretty much any possible context-sensitive
behavior.
A number of clever tricks for simulating various kinds of item
types can also be done by adjusting the values of
lbra
(default: [),
mark
(default: * for radio menus, X for check menus)
and
rbra
(default: ]) and declaring a reasonable
checked
hook,
which should return TRUE for the
"marked"
state and FALSE for
"unmarked".
The
aux
field is not used internally, and is available for miscellaneous usage.
If an item has a
fire
hook associated with it, it will also be called
whenever the item is "toggled" in some way and should return one of the
following codes:
#define DITEM_SUCCESS 0 /* Successful completion */
#define DITEM_FAILURE 1 /* Failed to "fire" */
The following flags are in the upper 16 bits of return status:
#define DITEM_LEAVE_MENU (1 << 16)
#define DITEM_REDRAW (1 << 17)
#define DITEM_RECREATE (1 << 18)
#define DITEM_RESTORE (1 << 19)
#define DITEM_CONTINUE (1 << 20)
Two special globals also exist for putting a dialog at any arbitrary
X,Y location (the early designers rather short-sightedly made no provisions
for this).
If set to zero, the default centering behavior will be in
effect.
Below is a short description of the various functions:
The
draw_shadow
function draws a shadow in curses window
win
using the dimensions of
x, y, width
and
height.
The
draw_box
function draws a bordered box using the dimensions of
x, y, width
and
height.
The attributes from
box
and
border
are used, if specified, while painting the box and border regions of the
object.
The
line_edit
function invokes a simple line editor with an edit box of dimensions
box_x, box_y
and
box_width.
The field length is constrained by
flen,
starting at the
first
character specified and
optionally displayed with character attributes
attr.
The string being edited is stored in
result.
Returns 0 on success, 1 on Cancel, and -1 on failure or ESC.
The
strheight
function returns the height of string in
p,
counting newlines.
The
strwidth
function returns the width of string in
p,
counting newlines.
The
dialog_create_rc
function dumps dialog library settings into
filename
for later retrieval as defaults.
Returns 0 on success, -1 on failure.
The
dialog_yesno
function displays a text box using
title
and
prompt
strings of dimensions
height
and
width.
Also paint a pair of
Yes
and
No
buttons at the bottom.
The default selection is
Yes.
If the
Yes
button is chosen, return FALSE.
If
No,
return TRUE.
The
dialog_noyes
function is the same as
dialog_yesno,
except the default selection is
No.
The
dialog_prgbox
function displays a text box of dimensions
height
and
width
containing the output of command
line.
If
use_shell
is TRUE,
line
is passed as an argument to
sh(1),
otherwise it is simply passed to
exec(3).
If
pause
is TRUE, a final confirmation requestor will be put up when execution
terminates.
Returns 0 on success, -1 on failure.
The
dialog_textbox
function displays a text box containing the contents of
file
with dimensions of
height
and
width.
The
dialog_menu
function displays a menu of dimensions
height
and
width
with an optional internal menu height of
menu_height.
The
cnt
and
it
arguments are of particular importance since they,
together, determine which of the 2 available APIs to use.
To use the
older and traditional interface,
cnt
should be a positive
integer representing the number of string pointer pairs to find in
it
(which should be of type
char **),
the strings are
expected to be in prompt and title order for each item and the
result
parameter is expected to point to an array where the
prompt string of the item selected will be copied.
To use the newer
interface,
cnt
should be a
negative
integer representing the number of
dialogMenuItem
structures pointed to by
it
(which should be of type
.Vt dialogMenuItem * ) ,
one structure per item.
In the new interface, the
result
variable is used as a simple boolean (not a pointer) and should be NULL if
it
only points to menu items and the default OK and Cancel buttons are desired.
If
result
is non-NULL, then
it
is actually expected to point 2 locations
past
the start of the menu item list.
it
is then expected to
point to an item representing the Cancel button, from which the
prompt
and
fire
actions are used to override the default behavior, and
it
to the same for the OK button.
Using either API behavior, the
ch
and
sc
values may be passed in to preserve current
item selection and scroll position values across calls.
The
dialog_checklist
function displays a menu of dimensions
height
and
width
with an
optional internal menu height of
list_height.
The
cnt
and
it
arguments are of particular importance since they,
together, determine which of the 2 available APIs to use.
To use the
older and traditional interface,
cnt
should be a positive
integer representing the number of string pointer tuples to find in
it
(which should be of type
char **),
the strings are
expected to be in prompt, title and state ("on" or "off") order for
each item and the
result
parameter is expected to point to an
array where the prompt string of the item(s) selected will be
copied.
To use the newer interface,
cnt
should be a
negative
integer representing the number of
dialogMenuItem
structures pointed to by
it
(which should be of type
dialogMenuItem *),
one structure per item.
In the new interface,
the
result
variable is used as a simple boolean (not a pointer)
and should be NULL if
it
only points to menu items and the default OK and Cancel
buttons are desired.
If
result
is non-NULL, then
it
is actually expected to
point 2 locations
past
the start of the menu item list.
it
is then expected to point to an item representing the Cancel
button, from which the
prompt
and
fire
actions are used to override the default behavior, and
it
to the same for the OK button.
In the standard API model, the menu supports the selection of multiple items,
each of which is marked with an X character to denote selection.
When
the OK button is selected, the prompt values for all items selected are
concatenated into the
result
string.
In the new API model, it is not actually necessary to preserve
"checklist" semantics at all since practically everything about how
each item is displayed or marked as "selected" is fully configurable.
You could have a single checklist menu that actually contained a group
of items with "radio" behavior, "checklist" behavior and standard menu
item behavior.
The only reason to call
dialog_checklist
over
dialog_radiolist
in the new API model is to inherit the base
behavior, you are no longer constrained by it.
Returns 0 on success, 1 on Cancel, and -1 on failure or ESC.
The
dialog_radiolist
function displays a menu of dimensions
height
and
width
with an
optional internal menu height of
list_height.
The
cnt
and
it
arguments are of particular importance since they,
together, determine which of the 2 available APIs to use.
To use the
older and traditional interface,
cnt
should be a positive
integer representing the number of string pointer tuples to find in
it
(which should be of type
char **),
the strings are
expected to be in prompt, title and state ("on" or "off") order for
each item and the
result
parameter is expected to point to an
array where the prompt string of the item(s) selected will be
copied.
To use the newer interface,
cnt
should be a
negative
integer representing the number of
dialogMenuItem
structures pointed to by
it
(which should be of type
dialogMenuItem *,
one structure per item.
In the new interface,
the
result
variable is used as a simple boolean (not a pointer)
and should be NULL if
it
only points to menu items and the default OK and Cancel
buttons are desired.
If
result
is non-NULL, then
it
is actually expected to point 2 locations
past
the start of the menu item list.
it
is then expected to point to an item representing the Cancel
button, from which the
prompt
and
fire
actions are used to override the default behavior, and
it
does the same for the traditional OK button.
In the standard API model, the menu supports the selection of only one
of multiple items, the currently active item marked with an *
character to denote selection.
When the OK button is selected, the
prompt value for this item is copied into the
result
string.
In the new API model, it is not actually necessary to preserve
"radio button" semantics at all since practically everything about how
each item is displayed or marked as "selected" is fully configurable.
You could have a single radio menu that actually contained a group
of items with "checklist" behavior, "radio" behavior and standard menu
item behavior.
The only reason to call
dialog_radiolist
over
dialog_checklistlist
in the new API model is to inherit the base
behavior.
Returns 0 on success, 1 on Cancel and -1 on failure or ESC.
The
dialog_inputbox
function displays a single-line text input field in a box displaying
title
and
prompt
of dimensions
height
and
width.
The field entered is stored in
result.
Returns 0 on success, -1 on failure or ESC.
The
dialog_fselect
function brings up a file selector dialog starting at
dir
and showing only those file names
matching
fmask.
Returns filename selected or NULL.
The
dialog_dselect
function brings up a directory selector dialog starting at
dir
and showing only those directory names
matching
fmask.
Returns directory name selected or NULL.
The
dialog_notify
function brings up a generic "hey, you!" notifier dialog containing
msg.
The
dialog_mesgbox
function displays a notifier dialog, but with more control over
title,
prompt,
width
and
height.
This object will also wait for user confirmation, unlike
dialog_notify.
Returns 0 on success, -1 on failure.
The
dialog_gauge
function displays a horizontal bar-graph style gauge.
A value of
100
for
perc
constitutes a full gauge, a value of
0
an empty one.
The
use_helpfile
function for any menu supporting context sensitive help, invokes the text box
object on this file whenever the
F1
key is pressed.
The
use_helpline
function displays this line of helpful text below any menu being displayed.
The
get_helpline
function gets the current value of the helpful text line.
The
dialog_clear_norefresh
function clears the screen back to the dialog background color, but do not
refresh the contents just yet.
The
dialog_clear
function clears the screen back to the dialog background color immediately.
The
dialog_update
function does any pending screen refreshes now.
The
init_dialog
function initializes the dialog library (call this routine before any other
dialog API calls).
The
end_dialog
function shuts down the dialog library (call this if you need to get back to
sanity).
The
dialog_ftree
function shows a tree described by the data from the file
filename.
The data in the file should look like
find(1)
output.
For the
find(1)
output, the field separator
FS
will be
"/".
If
height
and
width
are positive numbers, they set the absolute
size of the whole
dialog_ftree
box.
If
height
and
width
are negative numbers, the size of the
dialog_ftree
box will be calculated automatically.
menu_height
sets the height of the tree subwindow inside the
dialog_ftree
box and must be set.
title
is shown centered on the upper border of the
dialog_ftree
box.
prompt
is shown inside the
dialog_ftree
box above the tree subwindow and can contain
\n
to split lines.
One can navigate in
the tree by pressing UP/DOWN or
.Sm off
'+/'-'',
.Sm on
PG_UP/PG_DOWN or
.Sm off
'b/SPACE'
.Sm on
and
HOME/END or
.Sm off
'g/'G''.
.Sm on
A leaf of the
tree is selected by pressing TAB or LEFT/RIGHT the OK
button and pressing ENTER.
filename may contain data like
find(1)
output, as well as like the output of
find(1)
with
-d
option.
Some of the transient paths to the leaves of the tree may
be absent.
Such data is corrected when fed from filename.
The function returns 0 and a pointer to the selected leaf (to the path to
the leaf from the root of the tree) into result, if the OK button was
selected.
The memory allocated for the building of the tree is freed on
exiting
dialog_ftree.
The memory for the result line should be freed
later manually, if necessary.
If the Cancel button was selected, the
function returns 1.
In case of exiting
dialog_ftree
on ESC, the function returns -1.
The
dialog_tree
function returns the same results as
dialog_ftree.
If 0 is returned, result will contain a pointer from the array
names.