Commit 9bcb9ab0 authored by Kim F. Storm's avatar Kim F. Storm
Browse files

(Text Properties): Add "Enable Mouse-1" to submenu.

(Enabling Mouse-1 to Follow Links): New subsection.
parent 5304c40b
......@@ -2431,6 +2431,8 @@ along with the characters; this includes such diverse functions as
only when text is examined.
* Clickable Text:: Using text properties to make regions of text
do something when you click on them.
* Enabling Mouse-1 to Follow Links::
How to make @key{mouse-1} follow a link.
* Fields:: The @code{field} property defines
fields within the buffer.
* Not Intervals:: Why text properties do not use
......@@ -3388,6 +3390,110 @@ clickable pieces of text. Also, the major mode definition (or the
global definition) remains available for the rest of the text in the
buffer.
@node Enabling Mouse-1 to Follow Links
@subsection Enabling Mouse-1 to Follow Links
@cindex follow links
Traditionally, Emacs uses a @key{mouse-1} click to set point and a
@key{mouse-2} click to follow a link, whereas most other applications
use a @key{mouse-1} click for both purposes, depending on whether you
click outside or inside a link.
Starting with Emacs release 21.4, the user visible behaviour of a
@key{mouse-1} click on a link has been changed to match this
context-sentitive dual behaviour. The user can customize this
behaviour through the variable @code{mouse-1-click-follows-link}.
However, at the Lisp level, @key{mouse-2} is still used as the
action for the clickable text corresponding to the link, and the
clickable text must be explicitly marked as a link for a @key{mouse-1}
click to follow the link.
There are several methods that can be used to identify a clickable
text as a link:
@table @asis
@item follow-link property
If the clickable text has a non-nil @code{follow-link} text or overlay
property, the value of that property determines what to do.
@item follow-link event
If there is a binding for the @code{follow-link} event, either on
the clickable text or in the local keymap, the binding of that event
determines whether the mouse click position is inside a link:
@table @asis
@item mouse-face
If the binding is @code{mouse-face}, the mouse click position is
inside a link if there is a non-nil @code{mouse-face} property at
that position. A value of @code{t} is used to determine what to do next.
For example, here is how @key{mouse-1} are setup in info mode:
@example
(define-key Info-mode-map [follow-link] 'mouse-face)
@end example
@item a function
If the binding is a function, @var{func}, the mouse click position,
@var{pos}, is inside a link if the call @code{(@var{func} @var{pos})}
returns non-@code{nil}. The return value from that call determines
what to do next.
For example, here is how pcvs enables @key{mouse-1} on file names only:
@example
(define-key map [follow-link]
(lambda (pos)
(if (eq (get-char-property pos 'face) 'cvs-filename-face) t)))
@end example
@item anthing else
If the binding is anything else, the binding determines what to do.
@end table
@end table
@noindent
The resulting value determined above is interpreted as follows:
@table @asis
@item a string
If the value is a string, the @key{mouse-1} event is translated into
the first character of the string, i.e. the action of the @key{mouse-1}
click is the local or global binding of that character.
@item a vector
If the value is is a vector, the @key{mouse-1} event is translated
into the first element of that vector, i.e. the action of the
@key{mouse-1} click is the local or global binding of that event.
@item anthing else
For any other non-nil valule, the @key{mouse-1} event is translated
into a @key{mouse-2} event at the same position.
@end table
To use @key{mouse-1} on a button defined with @code{define-button-type},
give the button a @code{follow-link} property with a value as
specified above to determine how to follow the link.
To use @key{mouse-1} on a widget defined with @code{define-widget},
give the widget a @code{:follow-link} property with a value
as specified above to determine how to follow the link.
@defun mouse-on-link-p pos
@tindex mouse-on-link-p
Return non-@code{nil} if @var{pos} is on a link in the current buffer.
@end defun
@node Fields
@subsection Defining and Using Fields
@cindex fields
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment