Make 'fit-frame-to-buffer' work around size hints (Bug#74866)

* lisp/window.el (fit-frame-to-buffer-1): When
'frame-resize-pixelwise' is nil, round up requested sizes to avoid
that lines get wrapped (Bug#74866).
* doc/lispref/windows.texi (Resizing Windows): Mention that with
size hints one may have to set 'frame-resize-pixelwise' to make
'fit-frame-to-buffer' fit the buffer exactly.

1 files changed, 3 insertions, 1 deletions

diff --git a/doc/lispref/windows.texi b/doc/lispref/windows.texi
index adc294e4c99..3ff78b599de 100644
--- a/doc/lispref/windows.texi
+++ b/doc/lispref/windows.texi
@@ -1166,7 +1166,9 @@ frame to its buffer using the command @code{fit-frame-to-buffer}.
 This command adjusts the size of @var{frame} to display the contents of
 its buffer exactly.  @var{frame} can be any live frame and defaults to
 the selected one.  Fitting is done only if @var{frame}'s root window is
-live.
+a live window.  On window systems that use size hints, exact fitting can
+be often achieved if and only if @code{frame-resize-pixelwise}
+(@pxref{Frame Size}) is non-@code{nil}.
 
 The arguments @var{max-height}, @var{min-height}, @var{max-width} and
 @var{min-width}, if non-@code{nil}, specify bounds on the new body size