Various window code related fixes and documentation changes.

* dispnew.c (change_frame_size_1): Add new_lines instead of
new_height, the latter may be still zero if passed as such.
* window.c (Fwindow_pixel_height): Mention bottom divider in
doc-string.
* window.el (window-min-height, window-min-width): Rewrite
doc-strings.
(window-body-size): Add PIXELWISE argument to make it consistent
with its callees.
* display.texi (Window Dividers): New section.
* frames.texi (Layout Parameters): Add right-divider-width and
bottom-divider-width.
* windows.texi (Window Sizes): Redraw schematic and rewrite its
description.  Rewrite descriptions of `window-total-height',
`window-total-width', `window-total-size', `window-body-height',
`window-body-width' and `window-size-fixed'.  Add descriptions
for `window-pixel-height', `window-pixel-width',
`window-min-height' and `window-min-width'.  Remove description
of `window-size-fixed-p' moving part of it to that of
`window-size-fixed'.
(Resizing Windows): Mention dividers when talking about minimum
sizes.

1 files changed, 48 insertions, 0 deletions

diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 74a3172b75a..f22252143d7 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -24,6 +24,7 @@ that Emacs presents to the user.
                           font, colors, etc.
 * Fringes::             Controlling window fringes.
 * Scroll Bars::         Controlling vertical scroll bars.
+* Window Dividers::     Separating windows visually.
 * Display Property::    Enabling special display features.
 * Images::              Displaying images in Emacs buffers.
 * Buttons::             Adding clickable buttons to Emacs buffers.
@@ -3896,6 +3897,53 @@ buffer's scroll bars, measured in pixels.  A value of @code{nil} means
 to use the value specified by the frame.
 @end defvar
 
+@node Window Dividers
+@section Window Dividers
+@cindex window dividers
+@cindex right dividers
+@cindex bottom dividers
+
+Window dividers are bars drawn between a frame's windows.  A ``right''
+divider is drawn between a window and its sibling(s) on the right.  Its
+width is specified by the frame parameter @code{right-divider-width}.  A
+``bottom'' divider is drawn between a window and its sibling(s) on the
+bottom or the echo area.  Its width is specified by the frame parameter
+@code{bottom-divider-width}.  In either case, specifying a width of zero
+means to not draw such dividers.  @xref{Layout Parameters}.
+
+   Technically, a right divider ``belongs'' to the window on its left,
+which means that its width is part of the total width of that window.  A
+bottom divider ``belongs'' to the window above it, which means that its
+height is part of the total height of that window.  @xref{Window Sizes}.
+When a window has both, a right and a bottom divider, the bottom divider
+``prevails''.  This means that the width of the bottom divider equals
+the total width of the window while the height of the right divider
+equals the total height of the window minus the height of the bottom
+divider.
+
+   Dividers can be dragged with the mouse and are therefore useful for
+adjusting the sizes of adjacent windows with the mouse.  They also serve
+to set windows visually apart from their siblings when no scroll bars or
+mode lines are present.  The following three faces allow to customize
+the appearance of dividers:
+
+@table @code
+@item window-divider
+When a divider is less than three pixels wide, it is drawn solidly with
+the foreground of this face.  For larger dividers this face is used for
+the inner part only, exluding the first and last pixel.
+
+@item window-divider-first-pixel
+This is the face used for drawing the first pixel of a divider that is
+at least three pixels wide.  To obtain a solid appearance, set this to
+the same value used for the @code{window-divider} face.
+
+@item window-divider-last-pixel
+This is the face used for drawing the last pixel of a divider that is at
+least three pixels wide.  To obtain a solid appearance, set this to the
+same value used for the @code{window-divider} face.
+@end table
+
 @node Display Property
 @section The @code{display} Property
 @cindex display specification