Subject: Re: bug#4896: DocView: Continuous mode

From: Stefan Monnier <[email-masked]>
Date: Tue, 24 Nov 2009 14:48:36 -0500

> Any ideas how to specify doc-view scrolling functions for mwheel.el
> in doc-view continuous mode?

mwheel could introduce mwheel-scroll-up-function and
mwheel-scroll-up-function (with global defaults of scroll-up and
scroll-down, obviously) which doc-view could set buffer-locally.

Or we could rename scroll-up/down to scroll-up/down-internal and let
scroll-up/down obey new scroll-up/down-function hooks.

I guess starting with mwheel-scroll-up/down-function is less invasive.

        Stefan

> Index: lisp/mwheel.el
> ===================================================================
> RCS file: /sources/emacs/emacs/lisp/mwheel.el,v
> retrieving revision 1.56
> diff -u -r1.56 mwheel.el
> --- lisp/mwheel.el	12 Sep 2009 19:03:52 -0000	1.56
> +++ lisp/mwheel.el	24 Nov 2009 17:07:28 -0000
> @@ -206,7 +206,10 @@
>      (unwind-protect
>  	(let ((button (mwheel-event-button event)))
>  	  (cond ((eq button mouse-wheel-down-event)
> -                 (condition-case nil (scroll-down amt)
> +                 (condition-case nil
> +		     (if (eq major-mode 'doc-view-mode)
> +			 (doc-view-scroll-down-or-previous-page amt)
> +		       (scroll-down amt))
>                     ;; Make sure we do indeed scroll to the beginning of
>                     ;; the buffer.
>                     (beginning-of-buffer
> @@ -221,7 +224,10 @@
>                        ;; to only affect scroll-down.  --Stef
>                        (set-window-start (selected-window) (point-min))))))
>  		((eq button mouse-wheel-up-event)
> -                 (condition-case nil (scroll-up amt)
> +                 (condition-case nil
> +		     (if (eq major-mode 'doc-view-mode)
> +			 (doc-view-scroll-up-or-next-page amt)
> +		       (scroll-up amt))
>                     ;; Make sure we do indeed scroll to the end of the buffer.
>                     (end-of-buffer (while t (scroll-up)))))
>  		(t (error "Bad binding in mwheel-scroll"))))

> Index: lisp/doc-view.el
> ===================================================================
> RCS file: /sources/emacs/emacs/lisp/doc-view.el,v
> retrieving revision 1.90
> diff -u -r1.90 doc-view.el
> --- lisp/doc-view.el	24 Nov 2009 07:47:49 -0000	1.90
> +++ lisp/doc-view.el	24 Nov 2009 17:07:00 -0000
> @@ -431,24 +431,24 @@
>    (interactive)
>    (doc-view-goto-page (length doc-view-current-files)))
 
> -(defun doc-view-scroll-up-or-next-page ()
> +(defun doc-view-scroll-up-or-next-page (&optional n)
>    "Scroll page up if possible, else goto next page."
> -  (interactive)
> +  (interactive "^P")
>    (let ((hscroll (window-hscroll))
>  	(cur-page (doc-view-current-page)))
> -    (when (= (window-vscroll) (image-scroll-up nil))
> +    (when (= (window-vscroll) (image-scroll-up n))
>        (doc-view-next-page)
>        (when (/= cur-page (doc-view-current-page))
>  	(image-bob)
>  	(image-bol 1))
>        (set-window-hscroll (selected-window) hscroll))))
 
> -(defun doc-view-scroll-down-or-previous-page ()
> +(defun doc-view-scroll-down-or-previous-page (&optional n)
>    "Scroll page down if possible, else goto previous page."
> -  (interactive)
> +  (interactive "^P")
>    (let ((hscroll (window-hscroll))
>  	(cur-page (doc-view-current-page)))
> -    (when (= (window-vscroll) (image-scroll-down nil))
> +    (when (= (window-vscroll) (image-scroll-down n))
>        (doc-view-previous-page)
>        (when (/= cur-page (doc-view-current-page))
>  	(image-eob)

> -- 
> Juri Linkov
> http://www.jurta.org/emacs/