1 files changed, 205 insertions, 8 deletions

diff --git a/src/window.c b/src/window.c
index bf89f0e488b..4816bd69909 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1208,13 +1208,13 @@ coordinates_in_window (register struct window *w, int x, int y)
                      - WINDOW_BOTTOM_DIVIDER_WIDTH (w))))
     return ON_HORIZONTAL_SCROLL_BAR;
   /* On the mode or header line?   */
-  else if ((WINDOW_WANTS_MODELINE_P (w)
+  else if ((window_wants_mode_line (w)
             && y >= (bottom_y
                      - CURRENT_MODE_LINE_HEIGHT (w)
                      - WINDOW_BOTTOM_DIVIDER_WIDTH (w))
             && y <= bottom_y - WINDOW_BOTTOM_DIVIDER_WIDTH (w)
             && (part = ON_MODE_LINE))
-           || (WINDOW_WANTS_HEADER_LINE_P (w)
+           || (window_wants_header_line (w)
                && y < top_y + CURRENT_HEADER_LINE_HEIGHT (w)
                && (part = ON_HEADER_LINE)))
     {
@@ -1851,7 +1851,7 @@ Return nil if window display is not up-to-date.  In that case, use
 
   if (EQ (line, Qheader_line))
     {
-      if (!WINDOW_WANTS_HEADER_LINE_P (w))
+      if (!window_wants_header_line (w))
         return Qnil;
       row = MATRIX_HEADER_LINE_ROW (w->current_matrix);
       return row->enabled_p ? list4i (row->height, 0, 0, 0) : Qnil;
@@ -1898,6 +1898,129 @@ Return nil if window display is not up-to-date.  In that case, use
   return list4i (row->height + min (0, row->y) - crop, i, row->y, crop);
 }
 
+DEFUN ("window-lines-pixel-dimensions", Fwindow_lines_pixel_dimensions, Swindow_lines_pixel_dimensions, 0, 6, 0,
+       doc: /* Return pixel dimensions of WINDOW's lines.
+The return value is a list of the x- and y-coordinates of the lower
+right corner of the last character of each line.  Return nil if the
+current glyph matrix of WINDOW is not up-to-date.
+
+Optional argument WINDOW specifies the window whose lines' dimensions
+shall be returned.  Nil or omitted means to return the dimensions for
+the selected window.
+
+FIRST, if non-nil, specifies the index of the first line whose
+dimensions shall be returned.  If FIRST is nil and BODY is non-nil,
+start with the first text line of WINDOW.  Otherwise, start with the
+first line of WINDOW.
+
+LAST, if non-nil, specifies the last line whose dimensions shall be
+returned.  If LAST is nil and BODY is non-nil, the last line is the last
+line of the body (text area) of WINDOW.  Otherwise, last is the last
+line of WINDOW.
+
+INVERSE, if nil, means that the y-pixel value returned for a specific
+line specifies the distance in pixels from the left edge (body edge if
+BODY is non-nil) of WINDOW to the right edge of the last glyph of that
+line.  INVERSE non-nil means that the y-pixel value returned for a
+specific line specifies the distance in pixels from the right edge of
+the last glyph of that line to the right edge (body edge if BODY is
+non-nil) of WINDOW.
+
+LEFT non-nil means to return the x- and y-coordinates of the lower left
+corner of the leftmost character on each line.  This is the value that
+should be used for buffers that mostly display text from right to left.
+
+If LEFT is non-nil and INVERSE is nil, this means that the y-pixel value
+returned for a specific line specifies the distance in pixels from the
+left edge of the last (leftmost) glyph of that line to the right edge
+(body edge if BODY is non-nil) of WINDOW.  If LEFT and INVERSE are both
+non-nil, the y-pixel value returned for a specific line specifies the
+distance in pixels from the left edge (body edge if BODY is non-nil) of
+WINDOW to the left edge of the last (leftmost) glyph of that line.
+
+Normally, the value of this function is not available while Emacs is
+busy, for example, when processing a command.  It should be retrievable
+though when run from an idle timer with a delay of zero seconds.  */)
+  (Lisp_Object window, Lisp_Object first, Lisp_Object last, Lisp_Object body, Lisp_Object inverse, Lisp_Object left)
+{
+  struct window *w = decode_live_window (window);
+  struct buffer *b;
+  struct glyph_row *row, *end_row;
+  int max_y = NILP (body) ? WINDOW_PIXEL_HEIGHT (w) : window_text_bottom_y (w);
+  Lisp_Object rows = Qnil;
+  int window_width = NILP (body) ? w->pixel_width : window_body_width (w, true);
+  int header_line_height = WINDOW_HEADER_LINE_HEIGHT (w);
+  int subtract = NILP (body) ? 0 : header_line_height;
+  bool invert = !NILP (inverse);
+  bool left_flag = !NILP (left);
+
+  if (noninteractive || w->pseudo_window_p)
+    return Qnil;
+
+  CHECK_BUFFER (w->contents);
+  b = XBUFFER (w->contents);
+
+  /* Fail if current matrix is not up-to-date.  */
+  if (!w->window_end_valid
+      || windows_or_buffers_changed
+      || b->clip_changed
+      || b->prevent_redisplay_optimizations_p
+      || window_outdated (w))
+    return Qnil;
+
+  if (NILP (first))
+    row = (NILP (body)
+           ? MATRIX_ROW (w->current_matrix, 0)
+           : MATRIX_FIRST_TEXT_ROW (w->current_matrix));
+  else if (NUMBERP (first))
+    {
+      CHECK_RANGED_INTEGER (first, 0, w->current_matrix->nrows);
+      row = MATRIX_ROW (w->current_matrix, XINT (first));
+    }
+  else
+    error ("Invalid specification of first line");
+
+  if (NILP (last))
+
+    end_row = (NILP (body)
+               ? MATRIX_ROW (w->current_matrix, w->current_matrix->nrows)
+               : MATRIX_BOTTOM_TEXT_ROW (w->current_matrix, w));
+  else if (NUMBERP (last))
+    {
+      CHECK_RANGED_INTEGER (last, 0, w->current_matrix->nrows);
+      end_row = MATRIX_ROW (w->current_matrix, XINT (last));
+    }
+  else
+    error ("Invalid specification of last line");
+
+  while (row <= end_row && row->enabled_p
+         && row->y + row->height < max_y)
+    {
+
+      if (left_flag)
+        {
+          struct glyph *glyph = row->glyphs[TEXT_AREA];
+
+          rows = Fcons (Fcons (make_number
+                               (invert
+                                ? glyph->pixel_width
+                                : window_width - glyph->pixel_width),
+                               make_number (row->y + row->height - subtract)),
+                        rows);
+        }
+      else
+        rows = Fcons (Fcons (make_number
+                             (invert
+                              ? window_width - row->pixel_width
+                              : row->pixel_width),
+                             make_number (row->y + row->height - subtract)),
+                      rows);
+      row++;
+    }
+
+  return Fnreverse (rows);
+}
+
 DEFUN ("window-dedicated-p", Fwindow_dedicated_p, Swindow_dedicated_p,
        0, 1, 0,
        doc: /* Return non-nil when WINDOW is dedicated to its buffer.
@@ -2003,16 +2126,24 @@ return value is a list of elements of the form (PARAMETER . VALUE).  */)
   return Fcopy_alist (decode_valid_window (window)->window_parameters);
 }
 
+Lisp_Object
+window_parameter (struct window *w, Lisp_Object parameter)
+{
+  Lisp_Object result = Fassq (parameter, w->window_parameters);
+
+  return CDR_SAFE (result);
+}
+
+
 DEFUN ("window-parameter", Fwindow_parameter, Swindow_parameter,
        2, 2, 0,
        doc:  /* Return WINDOW's value for PARAMETER.
 WINDOW can be any window and defaults to the selected one.  */)
   (Lisp_Object window, Lisp_Object parameter)
 {
-  Lisp_Object result;
+  struct window *w = decode_any_window (window);
 
-  result = Fassq (parameter, decode_any_window (window)->window_parameters);
-  return CDR_SAFE (result);
+  return window_parameter (w, parameter);
 }
 
 DEFUN ("set-window-parameter", Fset_window_parameter,
@@ -4740,6 +4871,69 @@ mark_window_cursors_off (struct window *w)
 }
 
 
+/**
+ * window_wants_mode_line:
+ *
+ * Return 1 if window W wants a mode line and is high enough to
+ * accomodate it, 0 otherwise.
+ *
+ * W wants a mode line if it's a leaf window and neither a minibuffer
+ * nor a pseudo window.  Moreover, its 'window-mode-line-format'
+ * parameter must not be 'none' and either that parameter or W's
+ * buffer's 'mode-line-format' value must be non-nil.  Finally, W must
+ * be higher than its frame's canonical character height.
+ */
+bool
+window_wants_mode_line (struct window *w)
+{
+  Lisp_Object window_mode_line_format =
+    window_parameter (w, Qmode_line_format);
+
+  return ((WINDOW_LEAF_P (w)
+           && !MINI_WINDOW_P (w)
+           && !WINDOW_PSEUDO_P (w)
+           && !EQ (window_mode_line_format, Qnone)
+           && (!NILP (window_mode_line_format)
+               || !NILP (BVAR (XBUFFER (WINDOW_BUFFER (w)), mode_line_format)))
+           && WINDOW_PIXEL_HEIGHT (w) > WINDOW_FRAME_LINE_HEIGHT (w))
+          ? 1
+          : 0);
+}
+
+
+/**
+ * window_wants_header_line:
+ *
+ * Return 1 if window W wants a header line and is high enough to
+ * accomodate it, 0 otherwise.
+ *
+ * W wants a header line if it's a leaf window and neither a minibuffer
+ * nor a pseudo window.  Moreover, its 'window-mode-line-format'
+ * parameter must not be 'none' and either that parameter or W's
+ * buffer's 'mode-line-format' value must be non-nil.  Finally, W must
+ * be higher than its frame's canonical character height and be able to
+ * accomodate a mode line too if necessary (the mode line prevails).
+ */
+bool
+window_wants_header_line (struct window *w)
+{
+  Lisp_Object window_header_line_format =
+    window_parameter (w, Qheader_line_format);
+
+  return ((WINDOW_LEAF_P (w)
+           && !MINI_WINDOW_P (w)
+           && !WINDOW_PSEUDO_P (w)
+           && !EQ (window_header_line_format, Qnone)
+           && (!NILP (window_header_line_format)
+               || !NILP (BVAR (XBUFFER (WINDOW_BUFFER (w)), header_line_format)))
+           && (WINDOW_PIXEL_HEIGHT (w)
+               > (window_wants_mode_line (w)
+                  ? 2 * WINDOW_FRAME_LINE_HEIGHT (w)
+                  : WINDOW_FRAME_LINE_HEIGHT (w))))
+          ? 1
+          : 0);
+}
+
 /* Return number of lines of text (not counting mode lines) in W.  */
 
 int
@@ -4753,10 +4947,10 @@ window_internal_height (struct window *w)
           || WINDOWP (w->contents)
           || !NILP (w->next)
           || !NILP (w->prev)
-          || WINDOW_WANTS_MODELINE_P (w))
+          || window_wants_mode_line (w))
         --ht;
 
-      if (WINDOW_WANTS_HEADER_LINE_P (w))
+      if (window_wants_header_line (w))
         --ht;
     }
 
@@ -7354,6 +7548,8 @@ syms_of_window (void)
   DEFSYM (Qfloor, "floor");
   DEFSYM (Qceiling, "ceiling");
   DEFSYM (Qmark_for_redisplay, "mark-for-redisplay");
+  DEFSYM (Qmode_line_format, "mode-line-format");
+  DEFSYM (Qheader_line_format, "header-line-format");
 
   staticpro (&Vwindow_list);
 
@@ -7603,6 +7799,7 @@ displayed after a scrolling operation to be somewhat inaccurate.  */);
   defsubr (&Sset_window_point);
   defsubr (&Sset_window_start);
   defsubr (&Swindow_dedicated_p);
+  defsubr (&Swindow_lines_pixel_dimensions);
   defsubr (&Sset_window_dedicated_p);
   defsubr (&Swindow_display_table);
   defsubr (&Sset_window_display_table);