Improve indexing in Emacs manual (Bug#20105)

[gnu-emacs] / src / window.c

diff --git a/src/window.c b/src/window.c
index 3fefd9ce68292d1b126c66466daa54de7604cd8f..aafa4a16df1a9e7eca25160a7b8e86de530eb235 100644 (file)
--- a/src/window.c
+++ b/src/window.c
@@ -1,6 +1,6 @@
 /* Window creation, deletion and examination for GNU Emacs.
    Does not include redisplay.
-   Copyright (C) 1985-1987, 1993-1998, 2000-2014 Free Software
+   Copyright (C) 1985-1987, 1993-1998, 2000-2015 Free Software
    Foundation, Inc.
 
 This file is part of GNU Emacs.
@@ -973,7 +973,10 @@ or scroll bars.
 If PIXELWISE is nil, return the largest integer smaller than WINDOW's
 pixel width divided by the character width of WINDOW's frame.  This
 means that if a column at the right of the text area is only partially
-visible, that column is not counted.  */)
+visible, that column is not counted.
+
+Note that the returned value includes the column reserved for the
+continuation glyph.  */)
   (Lisp_Object window, Lisp_Object pixelwise)
 {
   return make_number (window_body_width (decode_live_window (window),
@@ -4804,10 +4807,10 @@ DEFUN ("resize-mini-window-internal", Fresize_mini_window_internal, Sresize_mini
       block_input ();
       window_resize_apply (r, 0);
 
-      w->total_lines = XFASTINT (w->new_total);
-      w->top_line = r->top_line + r->total_lines;
       w->pixel_height = XFASTINT (w->new_pixel);
+      w->total_lines = w->pixel_height / FRAME_LINE_HEIGHT (f);
       w->pixel_top = r->pixel_top + r->pixel_height;
+      w->top_line = r->top_line + r->total_lines;
 
       fset_redisplay (f);
       FRAME_WINDOW_SIZES_CHANGED (f) = 1;
@@ -4937,8 +4940,8 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, int noerror)
       /* The function move_iterator_vertically may move over more than
         the specified y-distance.  If it->w is small, e.g. a
         mini-buffer window, we may end up in front of the window's
-        display area.  This is the case when Start displaying at the
-        start of the line containing PT in this case.  */
+        display area.  Start displaying at the start of the line
+        containing PT in this case.  */
       if (it.current_y <= 0)
        {
          init_iterator (&it, w, PT, PT_BYTE, NULL, DEFAULT_FACE_ID);
@@ -4955,9 +4958,14 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, int noerror)
        {
          int px;
          int dy = frame_line_height;
+         /* In the below we divide the window box height by the
+            frame's line height to make the result predictable when
+            the window box is not an integral multiple of the line
+            height.  This is important to ensure we get back to the
+            same position when scrolling up, then down.  */
          if (whole)
-           dy = max ((window_box_height (w)
-                      - next_screen_context_lines * dy),
+           dy = max ((window_box_height (w) / dy
+                      - next_screen_context_lines) * dy,
                      dy);
          dy *= n;
 
@@ -5039,8 +5047,12 @@ window_scroll_pixel_based (Lisp_Object window, int n, bool whole, int noerror)
     {
       ptrdiff_t start_pos = IT_CHARPOS (it);
       int dy = frame_line_height;
-      dy = max ((window_box_height (w)
-                - next_screen_context_lines * dy),
+      /* In the below we divide the window box height by the frame's
+        line height to make the result predictable when the window
+        box is not an integral multiple of the line height.  This is
+        important to ensure we get back to the same position when
+        scrolling up, then down.  */
+      dy = max ((window_box_height (w) / dy - next_screen_context_lines) * dy,
                dy) * n;
 
       /* Note that move_it_vertically always moves the iterator to the
@@ -5897,6 +5909,8 @@ and redisplay normally--don't erase and redraw the frame.  */)
   w->start_at_line_beg = (bytepos == BEGV_BYTE ||
                          FETCH_BYTE (bytepos - 1) == '\n');
 
+  wset_redisplay (w);
+
   set_buffer_internal (obuf);
   return Qnil;
 }