NAME¶
Tk_CreateBindingTable, Tk_DeleteBindingTable, Tk_CreateBinding,
Tk_DeleteBinding, Tk_GetBinding, Tk_GetAllBindings, Tk_DeleteAllBindings,
Tk_BindEvent - invoke scripts in response to X events
SYNOPSIS¶
#include <tk.h>
Tk_BindingTable
Tk_CreateBindingTable(interp)
Tk_DeleteBindingTable(bindingTable)
unsigned long
Tk_CreateBinding(interp, bindingTable, object, eventString, script, append)
int
Tk_DeleteBinding(interp, bindingTable, object, eventString)
const char *
Tk_GetBinding(interp, bindingTable, object, eventString)
Tk_GetAllBindings(interp, bindingTable, object)
Tk_DeleteAllBindings(bindingTable, object)
Tk_BindEvent(bindingTable, eventPtr, tkwin, numObjects, objectPtr)
ARGUMENTS¶
- Tcl_Interp *interp (in)
- Interpreter to use when invoking bindings in binding table. Also used for
returning results and errors from binding procedures.
- Tk_BindingTable bindingTable (in)
- Token for binding table; must have been returned by some previous call to
Tk_CreateBindingTable.
- ClientData object (in)
- Identifies object with which binding is associated.
- const char *eventString (in)
- String describing event sequence.
- const char *script (in)
- Tcl script to invoke when binding triggers.
- int append (in)
- Non-zero means append script to existing script for binding, if
any; zero means replace existing script with new one.
- XEvent *eventPtr (in)
- X event to match against bindings in bindingTable.
- Tk_Window tkwin (in)
- Identifier for any window on the display where the event occurred. Used to
find display-related information such as key maps.
- int numObjects (in)
- Number of object identifiers pointed to by objectPtr.
- ClientData *objectPtr (in)
- Points to an array of object identifiers: bindings will be considered for
each of these objects in order from first to last.
DESCRIPTION¶
These procedures provide a general-purpose mechanism for creating and invoking
bindings. Bindings are organized in terms of
binding tables. A binding
table consists of a collection of bindings plus a history of recent events.
Within a binding table, bindings are associated with
objects. The
meaning of an object is defined by clients of the binding package. For
example, Tk keeps uses one binding table to hold all of the bindings created
by the
bind command. For this table, objects are pointers to strings
such as window names, class names, or other binding tags such as
all.
Tk also keeps a separate binding table for each canvas widget, which manages
bindings created by the canvas's
bind widget command; within this
table, an object is either a pointer to the internal structure for a canvas
item or a Tk_Uid identifying a tag.
The procedure
Tk_CreateBindingTable creates a new binding table and
associates
interp with it (when bindings in the table are invoked, the
scripts will be evaluated in
interp).
Tk_CreateBindingTable
returns a token for the table, which must be used in calls to other procedures
such as
Tk_CreateBinding or
Tk_BindEvent.
Tk_DeleteBindingTable frees all of the state associated with a binding
table. Once it returns the caller should not use the
bindingTable token
again.
Tk_CreateBinding adds a new binding to an existing table. The
object argument identifies the object with which the binding is to be
associated, and it may be any one-word value. Typically it is a pointer to a
string or data structure. The
eventString argument identifies the event
or sequence of events for the binding; see the documentation for the
bind command for a description of its format.
script is the Tcl
script to be evaluated when the binding triggers.
append indicates what
to do if there already exists a binding for
object and
eventString: if
append is zero then
script replaces the
old script; if
append is non-zero then the new script is appended to
the old one.
Tk_CreateBinding returns an X event mask for all the
events associated with the bindings. This information may be useful to invoke
XSelectInput to select relevant events, or to disallow the use of
certain events in bindings. If an error occurred while creating the binding
(e.g.,
eventString refers to a non-existent event), then 0 is returned
and an error message is left as the result of interpreter
interp.
Tk_DeleteBinding removes from
bindingTable the binding given by
object and
eventString, if such a binding exists.
Tk_DeleteBinding always returns
TCL_OK. In some cases it may
reset the interpreter result to the default empty value.
Tk_GetBinding returns a pointer to the script associated with
eventString and
object in
bindingTable. If no such
binding exists then NULL is returned and an error message is left as the
result of interpreter
interp.
Tk_GetAllBindings returns in
interp's result a list of all the
event strings for which there are bindings in
bindingTable associated
with
object. If there are no bindings for
object, the result
will be an empty string.
Tk_DeleteAllBindings deletes all of the bindings in
bindingTable
that are associated with
object.
Tk_BindEvent is called to process an event. It makes a copy of the event
in an internal history list associated with the binding table, then it checks
for bindings that match the event.
Tk_BindEvent processes each of the
objects pointed to by
objectPtr in turn. For each object, it finds all
the bindings that match the current event history, selects the most specific
binding using the priority mechanism described in the documentation for
bind, and invokes the script for that binding. If there are no matching
bindings for a particular object, then the object is skipped.
Tk_BindEvent continues through all of the objects, handling exceptions
such as errors,
break, and
continue as described in the
documentation for
bind.
KEYWORDS¶
binding, event, object, script