Event Types

The type field may be any of the standard X event types, with a few extra abbreviations. The type field will also accept a couple non-standard X event types that were added to better support the Macintosh and Windows platforms. Below is a list of all the valid types; where two names appear together, they are synonyms.

Activate
ButtonPress, Button
ButtonRelease
Circulate
CirculateRequest
Colormap
Configure
ConfigureRequest
Create
Leave
Deactivate
Destroy
Enter
Expose
FocusIn
FocusOut
Gravity
KeyPress, Key
KeyRelease
Visibility
Map
MapRequest
Motion
MouseWheel
Property
Reparent
ResizeRequest
Unmap

Most of the above events have the same fields and behaviors as events in the X Windowing system. You can find more detailed descriptions of these events in any X window programming book. A couple of the events are extensions to the X event system to support features unique to the Macintosh and Windows platforms. We provide a little more detail on these events here. These include:

Activate, Deactivate

These two events are sent to every sub-window of a toplevel when they change state. In addition to the focus Window, the Macintosh platform and Windows platforms have a notion of an active window (which often has but is not required to have the focus). On the Macintosh, widgets in the active window have a different appearance than widgets in deactive windows. The Activate event is sent to all the sub-windows in a toplevel when it changes from being deactive to active. Likewise, the Deactive event is sent when the window's state changes from active to deactive. There are no useful percent substitutions you would make when binding to these events.

MouseWheel

Some mice on the Windows platform support a mouse wheel which is used for scrolling documents without using the scrollbars. By rolling the wheel, the system will generate MouseWheel events that the application can use to scroll. On Windows, the event is always routed to the window that currently has focus. On Mac OS X, the event is routed to the window under the pointer. When the event is received you can use the %D substitution to get the delta field for the event which is a integer value of motion that the mouse wheel has moved. The smallest value for which the system will report is defined by the OS. On Windows 95 & 98 machines this value is at least 120 before it is reported. However, higher resolution devices may be available in the future. On Mac OS X, the value is not scaled by 120, but a value of 1 corresponds to roughly one text line. The sign of the value determines which direction your widget should scroll. Positive values should scroll up and negative values should scroll down.

The last part of a long event specification is detail. In the case of a ButtonPress or ButtonRelease event, it is the number of a button (1-5). If a button number is given, then only an event on that particular button will match; if no button number is given, then an event on any button will match. Note: giving a specific button number is different than specifying a button modifier; in the first case, it refers to a button being pressed or released, while in the second it refers to some other button that is already depressed when the matching event occurs. If a button number is given then type may be omitted: if will default to ButtonPress. For example, the specifier <1> is equivalent to <ButtonPress-1>.

If the event type is KeyPress or KeyRelease, then detail may be specified in the form of an X keysym. Keysyms are textual specifications for particular keys on the keyboard; they include all the alphanumeric ASCII characters (e.g. “a” is the keysym for the ASCII character “a”), plus descriptions for non-alphanumeric characters (“comma” is the keysym for the comma character), plus descriptions for all the non-ASCII keys on the keyboard (“Shift_L” is the keysm for the left shift key, and “F1” is the keysym for the F1 function key, if it exists). The complete list of keysyms is not presented here; it is available in other X documentation and may vary from system to system. If necessary, you can use the %K notation described below to print out the keysym name for a particular key. If a keysym detail is given, then the type field may be omitted; it will default to KeyPress. For example, <Control-comma> is equivalent to <Control-KeyPress-comma>.

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