Teach MS-Windows font back-end return per-glyph ascent/descent

* src/w32font.h (struct w32_metric_cache): Add ascent and descent
values.

* src/w32font.c (w32font_text_extents): Compute, cache, and
accumulate per-glyph ascent and descent values, instead of copying
global values from the font.  If the values are not available from
the font data, i.e., non-TTF fonts, fall back on font-global values.
(compute_metrics): Compute and return per-glyph ascent and descent
values, if returned by GetGlyphOutlineW, falling back on
font-global values.  (Bug#20628)

* src/w32term.c (w32_draw_rectangle): Add 1 pixel to width and
height of rectangle to be drawn, to be compatible with
XDrawRectangle.  Fixes glyphless-char display as hex codes in a
box, when per-glyph ascent/descent values are used.

1 files changed, 7 insertions, 1 deletions

diff --git a/src/w32term.c b/src/w32term.c
index 089c43c8a26..0bc2e980214 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -401,7 +401,13 @@ w32_draw_rectangle (HDC hdc, XGCValues *gc, int x, int y,
   oldhb = SelectObject (hdc, hb);
   oldhp = SelectObject (hdc, hp);
 
-  Rectangle (hdc, x, y, x + width, y + height);
+  /* We enlarge WIDTH and HEIGHT by 1 to be bug-compatible to the
+     brain-dead design of XDrawRectangle, which draws a rectangle that
+     is 1 pixel wider and higher than its arguments WIDTH and HEIGHT.
+     This allows us to keep the code that calls this function similar
+     to the corresponding code in xterm.c.  For the details, see
+     http://lists.gnu.org/archives/html/emacs-devel/2014-10/msg00546.html.  */
+  Rectangle (hdc, x, y, x + width + 1, y + height + 1);
 
   SelectObject (hdc, oldhb);
   SelectObject (hdc, oldhp);