-;;; mouse-drag.el -- use mouse-2 to do a new style of scrolling
-;; Copyright (C) 1996 Free Software Foundation, Inc.
+;;; mouse-drag.el --- use mouse-2 to do a new style of scrolling
+
+;; Copyright (C) 1996, 1997, 2001 Free Software Foundation, Inc.
;; Author: John Heidemann <johnh@ISI.EDU>
;; Keywords: mouse
;;;
;;; - reverse the throw-scroll direction with \\[mouse-throw-with-scroll-bar]
;;; - work around a bug with \\[mouse-extras-work-around-drag-bug]
+;;; - auto-enable horizontal scrolling with
+;;; \\[mouse-drag-electric-col-scrolling]
;;;
;;;
;;; History and related work:
;;; -johnh@isi.edu, 11-Jul-96
;;;
;;;
-;;; Old changes, for reference:
-;;;
-;;; What's new with mouse-extras 2.21?
+;;; What's new with mouse-drag 2.24?
;;;
-;;; - support for emacs-19.{29,30}
-;;; - point now stays on the visible screen during horizontal scrolling
-;;; (bug identified and fix suggested by Tom Wurgler <twurgler@goodyear.com>)
-;;; - better work-around for lost-mouse-events bug (supports double/triple
-;;; clicks), see \\[mouse-extras-work-around-drag-bug] for details.
-;;; - work-around for lost-mouse-events bug now is OFF by default;
-;;; enable it if you have problems
-;;;
-
-
+;;; - mouse-drag-electric-col-scrolling (default: on)
+;;; auto-enables horizontal scrolling when clicks on wrapped
+;;; lines occur
\f
;;; Code:
;;
(defun mouse-drag-safe-scroll (row-delta &optional col-delta)
- "* Scroll down ROW-DELTA lines and right COL-DELTA, ignoring buffer edge errors.
+ "Scroll down ROW-DELTA lines and right COL-DELTA, ignoring buffer edge errors.
Keep the cursor on the screen as needed."
- (if (and row-delta
- (/= 0 row-delta))
- (condition-case nil ;; catch and ignore movement errors
- (scroll-down row-delta)
- (beginning-of-buffer (message "Beginning of buffer"))
- (end-of-buffer (message "End of buffer"))))
- (if (and col-delta
- (/= 0 col-delta))
- (progn
- (scroll-right col-delta)
- ;; Make sure that the point stays on the visible screen
- ;; (if truncation-lines in set).
- ;; This code mimics the behavior we automatically get
- ;; when doing vertical scrolling.
- ;; Problem identified and a fix suggested by Tom Wurgler.
- (cond
- ((< (current-column) (window-hscroll))
- (move-to-column (window-hscroll))) ; make on left column
- ((> (- (current-column) (window-hscroll) (window-width) -2) 0)
- (move-to-column (+ (window-width) (window-hscroll) -3)))))))
+ (let ((scroll-preserve-screen-position nil))
+ (if (and row-delta
+ (/= 0 row-delta))
+ (condition-case nil ;; catch and ignore movement errors
+ (scroll-down row-delta)
+ (beginning-of-buffer (message "Beginning of buffer"))
+ (end-of-buffer (message "End of buffer"))))
+ (if (and col-delta
+ (/= 0 col-delta))
+ (progn
+ (scroll-right col-delta)
+ ;; Make sure that the point stays on the visible screen
+ ;; (if truncation-lines in set).
+ ;; This code mimics the behavior we automatically get
+ ;; when doing vertical scrolling.
+ ;; Problem identified and a fix suggested by Tom Wurgler.
+ (cond
+ ((< (current-column) (window-hscroll))
+ (move-to-column (window-hscroll))) ; make on left column
+ ((> (- (current-column) (window-hscroll) (window-width) -2) 0)
+ (move-to-column (+ (window-width) (window-hscroll) -3))))))))
(defun mouse-drag-repeatedly-safe-scroll (row-delta &optional col-delta)
- "* Scroll ROW-DELTA rows and COL-DELTA cols until an event happens."
+ "Scroll ROW-DELTA rows and COL-DELTA cols until an event happens."
(while (sit-for mouse-scroll-delay)
(mouse-drag-safe-scroll row-delta col-delta)))
(defun mouse-drag-events-are-point-events-p (start-posn end-posn)
- "* Determine if START-POSN and END-POSN are \"close\"."
+ "Determine if START-POSN and END-POSN are \"close\"."
(let*
((start-col-row (posn-col-row start-posn))
(end-col-row (posn-col-row end-posn)))
(= (car start-col-row) (car end-col-row))
(= (cdr start-col-row) (cdr end-col-row)))))
+(defvar mouse-drag-electric-col-scrolling t
+ "If non-nil, mouse-drag on a long line enables truncate-lines.")
+
(defun mouse-drag-should-do-col-scrolling ()
- "* Determine if it's wise to enable col-scrolling for the current window."
+ "Determine if it's wise to enable col-scrolling for the current window.
+Basically, we check for existing horizontal scrolling."
(or truncate-lines
(> (window-hscroll (selected-window)) 0)
- (< (window-width) (screen-width))))
+ (< (window-width) (frame-width))
+ (and
+ mouse-drag-electric-col-scrolling
+ (save-excursion ;; on a long line?
+ (let
+ ((beg (progn (beginning-of-line) (point)))
+ (end (progn (end-of-line) (point))))
+ (if (> (- end beg) (window-width))
+ (setq truncate-lines t)
+ nil))))))
(defvar mouse-throw-with-scroll-bar nil
- "* Set direction of mouse-throwing.
+ "*Set direction of mouse-throwing.
If nil, the text moves in the direction the mouse moves.
If t, the scroll bar moves in the direction the mouse moves.")
-(defconst mouse-throw-magnifier-with-scroll-bar
+(defconst mouse-throw-magnifier-with-scroll-bar
[-16 -8 -4 -2 -1 0 0 0 1 2 4 8 16])
(defconst mouse-throw-magnifier-with-mouse-movement
[ 16 8 4 2 1 0 0 0 -1 -2 -4 -8 -16])