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Cream of the Crop 21
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Cream of the Crop 21 (Terry Blount) (October 1996).iso
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avoid.el
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Lisp/Scheme
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1996-05-23
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15KB
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360 lines
;;; avoid.el --- make mouse pointer stay out of the way of editing
;;; Copyright (C) 1993, 1994 Free Software Foundation, Inc.
;; Author: Boris Goldowsky <boris@gnu.ai.mit.edu>
;; Keywords: mouse
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Commentary:
;; For those who are annoyed by the mouse pointer obscuring text,
;; this mode moves the mouse pointer - either just a little out of
;; the way, or all the way to the corner of the frame.
;; To use, load or evaluate this file and type M-x mouse-avoidance-mode .
;; To set up permanently, put the following in your .emacs:
;;
;; (if window-system (mouse-avoidance-mode 'animate))
;;
;; The 'animate can be 'jump or 'banish or 'exile or 'protean if you prefer.
;; See the documentation for function `mouse-avoidance-mode' for
;; details of the different modes.
;;
;; For added silliness, make the animatee animate...
;; put something similar to the following into your .emacs:
;;
;; (if window-system
;; (mouse-avoidance-set-pointer-shape
;; (eval (nth (random 4)
;; '(x-pointer-man x-pointer-spider
;; x-pointer-gobbler x-pointer-gumby)))))
;;
;; For completely random pointer shape, replace the setq above with:
;; (setq x-pointer-shape (mouse-avoidance-random-shape))
;;
;; Bugs / Warnings / To-Do:
;;
;; - Using this code does slow emacs down. "banish" mode shouldn't
;; be too bad, and on my workstation even "animate" is reasonable.
;;
;; - It ought to find out where any overlapping frames are and avoid them,
;; rather than always raising the frame.
;; Credits:
;; This code was helped by all those who contributed suggestions,
;; fixes, and additions
;; Joe Harrington (and his advisor), for the original inspiration.
;; Ken Manheimer, for dreaming up the Protean mode.
;; Richard Stallman, for the awful cat-and-mouse pun, among other things.
;; Mike Williams, Denis Howe, Bill Benedetto, Chris Moore, Don Morris,
;; Simon Marshall, and M.S. Ashton, for their feedback.
;;; Code:
(provide 'avoid)
(defvar mouse-avoidance-mode nil
"Value is t or a symbol if the mouse pointer should avoid the cursor.
See function `mouse-avoidance-mode' for possible values. Changing this
variable is NOT the recommended way to change modes; use that function
instead.")
(defvar mouse-avoidance-nudge-dist 15
"*Average distance that mouse will be moved when approached by cursor.
Only applies in mouse-avoidance-mode `jump' and its derivatives.
For best results make this larger than `mouse-avoidance-threshold'.")
(defvar mouse-avoidance-nudge-var 10
"*Variability of `mouse-avoidance-nudge-dist' (which see).")
(defvar mouse-avoidance-animation-delay .01
"Delay between animation steps, in seconds.")
(defvar mouse-avoidance-threshold 5
"*Mouse-pointer's flight distance.
If the cursor gets closer than this, the mouse pointer will move away.
Only applies in mouse-avoidance-modes `animate' and `jump'.")
;; Internal variables
(defvar mouse-avoidance-state nil)
(defvar mouse-avoidance-pointer-shapes nil)
(defvar mouse-avoidance-n-pointer-shapes 0)
(defvar mouse-avoidance-old-pointer-shape nil)
;;; Functions:
(defsubst mouse-avoidance-set-pointer-shape (shape)
"Set the shape of the mouse pointer to SHAPE."
(setq x-pointer-shape shape)
(set-mouse-color nil))
(defun mouse-avoidance-point-position ()
"Return the position of point as (FRAME X . Y).
Analogous to mouse-position."
(let* ((w (selected-window))
(edges (window-edges w))
(list
(compute-motion (max (window-start w) (point-min)) ; start pos
;; window-start can be < point-min if the
;; latter has changed since the last redisplay
'(0 . 0) ; start XY
(point) ; stop pos
(cons (window-width) (window-height)); stop XY: none
(1- (window-width)) ; width
(cons (window-hscroll w) 0) ; 0 may not be right?
(selected-window))))
;; compute-motion returns (pos HPOS VPOS prevhpos contin)
;; we want: (frame hpos . vpos)
(cons (selected-frame)
(cons (+ (car edges) (car (cdr list)))
(+ (car (cdr edges)) (car (cdr (cdr list))))))))
;(defun mouse-avoidance-point-position-test ()
; (interactive)
; (message (format "point=%s mouse=%s"
; (cdr (mouse-avoidance-point-position))
; (cdr (mouse-position)))))
(defun mouse-avoidance-set-mouse-position (pos)
;; Carefully set mouse position to given position (X . Y)
;; Ideally, should check if X,Y is in the current frame, and if not,
;; leave the mouse where it was. However, this is currently
;; difficult to do, so we just raise the frame to avoid frame switches.
;; Returns t if it moved the mouse.
(let ((f (selected-frame)))
(raise-frame f)
(set-mouse-position f (car pos) (cdr pos))
t))
(defun mouse-avoidance-too-close-p (mouse)
;; Return t if mouse pointer and point cursor are too close.
;; Acceptable distance is defined by mouse-avoidance-threshold.
(let ((point (mouse-avoidance-point-position)))
(and (eq (car mouse) (car point))
(car (cdr mouse))
(< (abs (- (car (cdr mouse)) (car (cdr point))))
mouse-avoidance-threshold)
(< (abs (- (cdr (cdr mouse)) (cdr (cdr point))))
mouse-avoidance-threshold))))
(defun mouse-avoidance-banish-destination ()
"The position to which mouse-avoidance-mode `banish' moves the mouse.
You can redefine this if you want the mouse banished to a different corner."
(cons (1- (frame-width))
0))
(defun mouse-avoidance-banish-mouse ()
;; Put the mouse pointer in the upper-right corner of the current frame.
(mouse-avoidance-set-mouse-position (mouse-avoidance-banish-destination)))
(defsubst mouse-avoidance-delta (cur delta dist var min max)
;; Decide how far to move in either dimension.
;; Args are the CURRENT location, the desired DELTA for
;; warp-conservation, the DISTANCE we like to move, the VARIABILITY
;; in distance allowed, and the MIN and MAX possible window positions.
;; Returns something as close to DELTA as possible within the constraints.
(let ((L1 (max (- min cur) (+ (- dist) (- var))))
(R1 (+ (- dist) var ))
(L2 (+ dist (- var)))
(R2 (min (- max cur) (+ dist var))))
(if (< R1 (- min cur)) (setq L1 nil R1 nil))
(if (> L2 (- max cur)) (setq L2 nil R2 nil))
(cond ((and L1 (< delta L1)) L1)
((and R1 (< delta R1)) delta)
((and R1 (< delta 0)) R1)
((and L2 (< delta L2)) L2)
((and R2 (< delta R2)) delta)
(R2)
((or R1 L2))
(t 0))))
(defun mouse-avoidance-nudge-mouse ()
;; Push the mouse a little way away, possibly animating the move
;; For these modes, state keeps track of the total offset that we've
;; accumulated, and tries to keep it close to zero.
(let* ((cur (mouse-position))
(cur-frame (car cur))
(cur-pos (cdr cur))
(deltax (mouse-avoidance-delta
(car cur-pos) (- (random mouse-avoidance-nudge-var)
(car mouse-avoidance-state))
mouse-avoidance-nudge-dist mouse-avoidance-nudge-var
0 (frame-width)))
(deltay (mouse-avoidance-delta
(cdr cur-pos) (- (random mouse-avoidance-nudge-var)
(cdr mouse-avoidance-state))
mouse-avoidance-nudge-dist mouse-avoidance-nudge-var
0 (frame-height))))
(setq