[Emacs-diffs] Changes to emacs/lispref/display.texi

[Kim F . Storm]

Index: emacs/lispref/display.texi
diff -c emacs/lispref/display.texi:1.134 emacs/lispref/display.texi:1.135
*** emacs/lispref/display.texi:1.134    Thu Nov 25 03:12:24 2004
--- emacs/lispref/display.texi  Fri Dec 10 23:58:02 2004
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*** 23,28 ****
--- 23,29 ----
  * Temporary Displays::  Displays that go away automatically.
  * Overlays::            Use overlays to highlight parts of the buffer.
  * Width::               How wide a character or string is on the screen.
+ * Line Height::         Controlling the height of lines.
  * Faces::               A face defines a graphics style for text characters:
                            font, colors, etc.
  * Fringes::             Controlling window fringes.
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*** 1510,1515 ****
--- 1511,1595 ----
  @end example
  @end defun
  
+ @node Line Height
+ @section Line Height
+ @cindex line height
+ 
+   The total height of each display line consists of the height of the
+ contents of the line, and additional vertical line spacing below the
+ display row.
+ 
+   The height of the line contents is normally determined from the
+ maximum height of any character or image on that display line,
+ including the final newline if there is one.  (A line that is
+ continued doesn't include a final newline.)  In the most common case,
+ the line height equals the height of the default frame font.
+ 
+   There are several other ways to change the line height, either by
+ specifying an absolute height for the display line, or by adding
+ additional vertical space below each line.
+ 
+ @kindex line-height @r{(text property)}
+   A newline can have a @code{line-height} text or overlay property that
+ controls the total height of the display line ending in that newline.
+ We will call the property value @var{line-height}.
+ 
+   If @var{line-height} property is 0, the height of the line is
+ determined solely from its contents; nothing is added.  Any
+ @code{line-spacing} property on this newline is ignored.  This case is
+ useful for tiling small images or image slices without adding blank
+ areas between the images.
+ 
+   If @var{line-height} property is a positive integer, the value
+ specifies the minimum line height in pixels.  The line's ascent height
+ is increased as necessary to achieve the specified height.
+ 
+   If @var{line-height} property is a floating point number, the
+ minimum line height is the product of @var{line-height} and the
+ default frame line height.
+ 
+   If @var{line-height} property is a cons @code{(@var{ratio} . @var{face})},
+ the minimum line height is calculated as @var{ratio} times the height
+ of face @var{face}.  The @var{ratio} is an integer or a floating point
+ number.  If @var{face} is @code{t}, it refers to the current face.
+ 
+ @vindex default-line-spacing
+   You can specify additional line spacing for all lines in a frame
+ with the @code{line-spacing} frame parameter, @xref{Window Frame
+ Parameters}.  However, if the variable @code{default-line-spacing} is
+ address@hidden, it overrides the frame's @code{line-spacing}
+ parameter.  An integer value specifies the number of pixels put below
+ lines on window systems.  A floating point number specifies the
+ spacing relative to the default frame line height.
+ 
+ @vindex line-spacing
+   You can specify additional line spacing for all lines in a buffer
+ via the buffer-local @code{line-spacing} variable.  An integer value
+ specifies the number of pixels put below lines on window systems.  A
+ floating point number specifies the spacing relative to the default
+ frame line height.
+ 
+ @kindex line-spacing @r{(text property)}
+   Finally, a newline can have a @code{line-spacing} text or overlay
+ property that controls the height of the display line ending with that
+ newline.  The property value overrides the default frame line spacing
+ and the buffer local @code{line-spacing} variable.  We will call the
+ property value @var{line-spacing}.
+ 
+   If the @var{line-spacing} value is a positive integer, the value
+ specifies additional vertical space, below the display line, in
+ pixels.
+ 
+   If the @var{line-spacing} value is a floating point number or cons,
+ the additional vertical space is the product of @var{line-spacing} and
+ the default frame line height.
+ 
+   If the @var{line-spacing} value is a cons @code{(total . @var{spacing})}
+ where @var{spacing} is any of the forms described above, the value of
+ @var{spacing} specifies the total displayed height of the line,
+ regardless of the height of the characters in it.  This is equivalent
+ to using the @code{line-height} property.
+ 
  @node Faces
  @section Faces
  @cindex faces
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*** 2826,2832 ****
  @code{scroll-bar-width} specifies how wide they are (@code{nil}
  meaning the default).  @xref{Window Frame Parameters}.
  
! You can also control this for individual windows.  Call the function
  @code{set-window-scroll-bars} to specify what to do for a specific window:
  
  @defun set-window-scroll-bars window width &optional vertical-type 
horizontal-type
--- 2906,2919 ----
  @code{scroll-bar-width} specifies how wide they are (@code{nil}
  meaning the default).  @xref{Window Frame Parameters}.
  
! @vindex vertical-scroll-bar
!   You can enable or disable scroll bars for a particular buffer,
! by setting the variable @code{vertical-scroll-bar}.  This variable
! automatically becomes buffer-local when set.  The possible values are
! @code{left}, @code{right}, @code{t}, which means to use the
! frame's default, and @code{nil} for no scroll bar.
! 
!   You can also control this for individual windows.  Call the function
  @code{set-window-scroll-bars} to specify what to do for a specific window:
  
  @defun set-window-scroll-bars window width &optional vertical-type 
horizontal-type