Add new functions for computing character metrics for windows

* doc/lispref/display.texi (Size of Displayed Text): Document the
char functions.
* doc/lispref/windows.texi (Window Sizes): Document
window-max-characters-per-line.

* lisp/window.el (window-char-pixel-width)
(window-char-pixel-height)
(window-max-characters-per-line): New functions (bug#19395).

1 files changed, 3 insertions, 1 deletions

diff --git a/src/window.c b/src/window.c
index ad0f54000c0..cfe3977428b 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1079,7 +1079,9 @@ means that if a column at the right of the text area is only partially
 visible, that column is not counted.
 
 Note that the returned value includes the column reserved for the
-continuation glyph.  */)
+continuation glyph.
+
+Also see `window-max-characters-per-line'.  */)
   (Lisp_Object window, Lisp_Object pixelwise)
 {
   return make_fixnum (window_body_width (decode_live_window (window),