bug#74701: 31.0.50; vtable: cannot drag to resize columns when :use-header-line is nil

[Eli Zaretskii <eliz@gnu.org>]

Ping!

> Cc: 74701@debbugs.gnu.org
> Date: Sat, 21 Dec 2024 11:10:28 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> 
> Adam, any comments?
> 
> > Cc: Adam Porter <adam@alphapapa.net>
> > From: Visuwesh <visuweshm@gmail.com>
> > Date: Thu, 05 Dec 2024 20:01:41 +0530
> > 
> > When creating a vtable with :use-header-line nil (see below), dragging
> > the column or the divider to resize the column is impossible because
> > 
> >   1. the function vtable--insert-header-line does not create the keymap
> >      so that non-header-line mouse bindings actually resize the column
> >   2. after inserting the header-line, vtable-insert completely
> >      overwrites the keymap text-property which wipes out the keymap
> >      setup by vtable--insert-header-line
> > 
> > To reproduce,
> > 
> >   1. emacs -Q
> >   2. Evaluate the following sexp
> > 
> >       (with-current-buffer (get-buffer-create "asd")
> >         (erase-buffer)
> >         (require 'vtable)
> >         (make-vtable
> >          :use-header-line nil
> >          :columns '("One" "Two")
> >          :objects '((1 2) (3 4) (5 6)))
> >         (pop-to-buffer (current-buffer)))    
> >   3. Try to resize the column "Two" ("T" is shown here) by clicking on
> >      "T" and dragging the pointer.
> >   4. Witness no column resize.
> >   5. Now, change :use-header-line to t and try to resize again.
> >   6. Witness column resize.
> > 
> > The patch below fixes the issue on my end
> > 
> > 
> > diff --git a/lisp/emacs-lisp/vtable.el b/lisp/emacs-lisp/vtable.el
> > index c4f14d7b4b2..6f04eca3da8 100644
> > --- a/lisp/emacs-lisp/vtable.el
> > +++ b/lisp/emacs-lisp/vtable.el
> > @@ -544,7 +544,7 @@ vtable-insert
> >          ;; them).
> >          (vtable--insert-header-line table widths spacer)
> >          (add-text-properties start (point)
> > -                             (list 'keymap vtable-header-line-map
> > +                             (list ;;'keymap vtable-header-line-map
> >                                     'rear-nonsticky t
> >                                     'vtable table))
> >          (setq start (point))))
> > @@ -706,24 +706,34 @@ vtable--indicator
> >  
> >  (defun vtable--insert-header-line (table widths spacer)
> >    ;; Insert the header directly into the buffer.
> > -  (let ((start (point))
> > -        (divider (vtable-divider table))
> > -        (cmap (define-keymap
> > -                "<header-line> <drag-mouse-1>" #'vtable--drag-resize-column
> > -                "<header-line> <down-mouse-1>" #'ignore))
> > -        (dmap (define-keymap
> > -                "<header-line> <drag-mouse-1>"
> > -                (lambda (e)
> > -                  (interactive "e")
> > -                  (vtable--drag-resize-column e t))
> > -                "<header-line> <down-mouse-1>" #'ignore)))
> > +  (let* ((start (point))
> > +         (divider (vtable-divider table))
> > +         (rev-resize-fun (lambda (e)
> > +                           (interactive "e")
> > +                           (vtable--drag-resize-column e t)))
> > +         (cmap (define-keymap
> > +                 :parent vtable-header-line-map
> > +                 "<header-line> <drag-mouse-1>" #'vtable--drag-resize-column
> > +                 "<header-line> <down-mouse-1>" #'ignore
> > +                 "<drag-mouse-1>" #'vtable--drag-resize-column
> > +                 "<down-mouse-1>" #'ignore))
> > +         (dmap (define-keymap
> > +                 :parent vtable-header-line-map
> > +                 "<header-line> <drag-mouse-1>" rev-resize-fun
> > +                 "<header-line> <down-mouse-1>" #'ignore
> > +                 "<drag-mouse-1>" rev-resize-fun
> > +                 "<down-mouse-1>" #'ignore)))
> >      (seq-do-indexed
> >       (lambda (column index)
> >         (let* ((name (propertize
> >                       (vtable-column-name column)
> >                       'face (list 'header-line (vtable-face table))
> >                       'mouse-face 'header-line-highlight
> > -                     'keymap cmap))
> > +                     ;; Reverse resizing is more intuitive for the first
> > +                     ;; column.
> > +                     'keymap (if (= index 0)
> > +                                 dmap
> > +                               cmap)))
> >                (start (point))
> >                (indicator (vtable--indicator table index))
> >                (indicator-width (string-pixel-width indicator))
> > 
> > 
> > I also took the liberty to make one other change:
> > 
> >     I use DMAP instead of CMAP for the first column.  Without this
> >     change, dragging the first column does nothing.  With this change,
> >     dragging the first column to the left will increase its size.  I
> >     think this behaviour is more intuitive than doing nothing.
> > 
> > In GNU Emacs 31.0.50 (build 25, x86_64-pc-linux-gnu, X toolkit, cairo
> >  version 1.18.2, Xaw scroll bars) of 2024-11-10 built on astatine
> > Repository revision: 1704fa4fb4164a15c7e258b922dbba190811d92d
> > Repository branch: master
> > Windowing system distributor 'The X.Org Foundation', version 11.0.12101014
> > System Description: Debian GNU/Linux trixie/sid
> > 
> > Configured using:
> >  'configure --with-sound=alsa --with-x-toolkit=lucid --without-xaw3d
> >  --without-gconf --without-libsystemd --with-cairo CFLAGS=-g3'
> > Configured features:
> > ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
> > LCMS2 LIBOTF LIBSELINUX LIBXML2 MODULES NOTIFY INOTIFY PDUMPER PNG RSVG
> > SECCOMP SOUND SQLITE3 THREADS TIFF TOOLKIT_SCROLL_BARS WEBP X11 XDBE XIM
> > XINPUT2 XPM LUCID ZLIB
> > Important settings:
> >   value of $LC_MONETARY: ta_IN.UTF-8
> >   value of $LC_NUMERIC: ta_IN.UTF-8
> >   value of $LANG: en_GB.UTF-8
> >   locale-coding-system: utf-8-unix
> 
> 
> 
>