bug#2618: 23.0.90; Point shifts leftward during vertical motion in buffaced buffer

bug#2618: 23.0.90; Point shifts leftward during vertical motion in buffaced buffer

[sand]

Open a text file and shrink the text size (using bufface) to -2.  Move
the cursor right several glyphs from the beginning of the line, then
move the cursor down one line.  On my machine, the cursor moves down,
but also moves left one glyph.  After any left or right cursor motion,
the next upward or downward cursor motion shifts the cursor one glyph
towards the left margin; further vertical motion is not affected.  The
problem stops when you return to normal fact size.

This is with fonts

  -jmk-Neep Alt-normal-normal-normal-*-20-*-*-*-c-*-iso10646-1 (bufface  0)
  -jmk-Neep Alt-normal-normal-normal-*-15-*-*-*-c-*-iso10646-1 (bufface -2)
  -jmk-Neep Alt-normal-normal-normal-*-11-*-*-*-c-*-iso10646-1 (bufface -4)

from the Debian distribution.


In GNU Emacs 23.0.90.1 (i486-pc-linux-gnu, GTK+ Version 2.12.11)
 of 2009-02-07 on elegiac, modified by Debian
 (emacs-snapshot package, version 1:20090207-1)
Windowing system distributor `The X.Org Foundation', version 11.0.10402000
configured using `configure  '--build' 'i486-linux-gnu' '--host' 'i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' '--localstatedir=/var' '--infodir=/usr/share/info' '--mandir=/usr/share/man' '--with-pop=yes' '--enable-locallisppath=/etc/emacs-snapshot:/etc/emacs:/usr/local/share/emacs/23.0.90/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/23.0.90/site-lisp:/usr/share/emacs/site-lisp' '--with-x=yes' '--with-x-toolkit=gtk' 'build_alias=i486-linux-gnu' 'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN -DSITELOAD_PURESIZE_EXTRA=5000 -g -O2' 'LDFLAGS=-g -Wl,--as-needed' 'CPPFLAGS=''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: POSIX
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_US.UTF-8
  value of $XMODIFIERS: nil
  locale-coding-system: utf-8-unix
  default-enable-multibyte-characters: t

Major mode: VM Presentation

Minor modes in effect:
  text-scale-mode: t
  shell-dirtrack-mode: t
  auto-image-file-mode: t
  show-paren-mode: t
  icomplete-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

bug#2618: 23.0.90; Point shifts leftward during vertical motion in buffaced buffer

[Chong Yidong]

> Open a text file and shrink the text size (using bufface) to -2.  Move
> the cursor right several glyphs from the beginning of the line, then
> move the cursor down one line.  On my machine, the cursor moves down,
> but also moves left one glyph.  After any left or right cursor motion,
> the next upward or downward cursor motion shifts the cursor one glyph
> towards the left margin; further vertical motion is not affected.  The
> problem stops when you return to normal fact size.

I am afraid you lost me at the first line: I don't know what `bufface'
is.  Please provide an *exact* recipe, including the precise file you
used and the precise steps you took beginning with `emacs -Q'.

bug#2618: 23.0.90; Point shifts leftward during vertical motion in buffaced buffer

[Kenichi Handa]

In article <20090309235924.10763.qmail@priss.frightenedpiglet.com>, sand@blarg.net writes:

> Open a text file and shrink the text size (using bufface) to -2.  Move
> the cursor right several glyphs from the beginning of the line, then
> move the cursor down one line.  On my machine, the cursor moves down,
> but also moves left one glyph.  After any left or right cursor motion,
> the next upward or downward cursor motion shifts the cursor one glyph
> towards the left margin; further vertical motion is not affected.  The
> problem stops when you return to normal fact size.

I can reproduce it with almost any fonts.  It seems that the
problem is that line-move-visual uses (frame-char-width) to
calculate the gloal column, but (frame-char-width) doesn't
change by remapping of the default face.  At the moment, I
don't know how to fix it.

---
Kenichi Handa
handa@m17n.org

bug#2618: 23.0.90; Point shifts leftward during vertical motion in buffaced buffer

[Chong Yidong]

Kenichi Handa <handa@m17n.org> writes:

> It seems that the problem is that line-move-visual uses
> (frame-char-width) to calculate the gloal column, but
> (frame-char-width) doesn't change by remapping of the default face.

I believe this old bug is obsolete, since line-move-visual nowadays uses
vertical-motion, which is pixel-based.  Closing.