Minor Cleartype rendering bug

[Geoff Gole]

Running emacs 22 under windows xp, I'm seeing a minor text rendering
error when Cleartype is enabled. The error appears to be that the very
last column of pixels is missing from a string of text of any one face
- that is, where text changes from one face to another. This occurs
under the following conditions:

Cleartype is enabled.
Emacs is displaying a fontified buffer using any truetype or opentype font.

The error does not appear if:

Cleartype is disabled.
Emacs is displaying text using any bitmap font.
Emacs is displaying a buffer that is not fontified, or otherwise is
displaying only a single face.

I tested on Emacs 22.1.50.1 and 22.0.99.1 with consistent results.

An image showing the difference between a fontified and plain buffer
is at http://img266.imageshack.us/img266/1254/emacscleartypebugdg9.png
(apologies for using imageshack, my hosting is currently down)

Face colours are set by the following function:

(defun my-color-scheme-light ()
"Fire up my colour scheme: light version."
    (interactive)
    (set-face-foreground  'default "black")
    (set-face-background  'default "gray90")
    (set-face-foreground  'font-lock-builtin-face "dark green")
    (set-face-foreground  'font-lock-comment-face "LightSkyBlue4")
    (set-face-background  'font-lock-comment-face "gray90")
    (set-face-italic-p    'font-lock-comment-face t)
    (set-face-foreground  'font-lock-function-name-face "blue3")
    (set-face-bold-p      'font-lock-function-name-face nil)
    (set-face-underline-p 'font-lock-function-name-face nil)
    (set-face-foreground  'font-lock-keyword-face "black")
    (set-face-bold-p      'font-lock-keyword-face t)
    (set-face-foreground  'font-lock-string-face "firebrick")
    (set-face-foreground  'font-lock-variable-name-face "black")
    (set-face-foreground  'font-lock-type-face "black")
    (set-face-foreground  'font-lock-constant-face "black")
    (set-face-foreground  'font-lock-warning-face "red")
    (set-face-foreground  'modeline "black")
    (set-face-background  'modeline "grey")
    (set-face-background  'cursor "black")
    (set-face-background  'region "lightgoldenrod")
    (set-face-background  'fringe "gray85")
    (set-face-background  'tabbar-default-face "gray85")
    (set-face-foreground  'tabbar-default-face "gray30")
    (set-face-foreground  'tabbar-unselected-face "gray40")
    (set-face-foreground  'tabbar-selected-face "blue")
    (set-face-foreground  'tabbar-button-face "gray40")
)

Output from report-emacs-bug:

In GNU Emacs 22.1.50.1 (i386-mingw-nt5.1.2600)
of 2007-05-01 on LENNART-69DE564
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --cflags -Ic:/g/include'

Important settings:
value of $LC_ALL: nil
value of $LC_COLLATE: nil
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: ENA
locale-coding-system: cp1252
default-enable-multibyte-characters: t

Major mode: C/l

Minor modes in effect:
delete-selection-mode: t
encoded-kbd-mode: t
tooltip-mode: t
mouse-wheel-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
font-lock-mode: t
blink-cursor-mode: t
unify-8859-on-encoding-mode: t
utf-translate-cjk-mode: t
auto-compression-mode: t
line-number-mode: t
transient-mark-mode: t
abbrev-mode: t

Recent input:
<help-echo> <drag-n-drop> <down-mouse-1> <mouse-1>
M-x r e p o r t <tab> <return>

Recent messages:
Loading c:/ggole/emacs/modes-cfg/c++.el (source)...done
Loading c:/ggole/emacs/modes.el (source)...done
Loading cl-macs...done
Loading cl-seq...done
Loading easy-mmode...done
For information about the GNU Project and its goals, type C-h C-p.
Loading url-util...done
Loading cc-mode...done
ggole C Style entered.
Loading emacsbug...done