(update_frame_line): Rename parameter FRAME to F.

Avoid some unnecessary cursor positioning.

2 files changed, 39 insertions, 20 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index df8e58ac4bc..f0b7c6ef2b5 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2001-02-06  Gerd Moellmann  <gerd@gnu.org>
+
+        * dispnew.c (update_frame_line): Rename parameter FRAME to F.
+        Avoid some unnecessary cursor positioning.
+
 2001-02-05  Gerd Moellmann  <gerd@gnu.org>
 
         * xfaces.c (split_font_name): Compute numeric value of
diff --git a/src/dispnew.c b/src/dispnew.c
index c7a65823819..be75ffe24b4 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -5334,20 +5334,20 @@ extern int *char_ins_del_vector;
 /* Perform a frame-based update on line VPOS in frame FRAME.  */
 
 static void
-update_frame_line (frame, vpos)
-     register struct frame *frame;
+update_frame_line (f, vpos)
+     struct frame *f;
      int vpos;
 {
   struct glyph *obody, *nbody, *op1, *op2, *np1, *nend;
   int tem;
   int osp, nsp, begmatch, endmatch, olen, nlen;
-  struct glyph_matrix *current_matrix = frame->current_matrix;
-  struct glyph_matrix *desired_matrix = frame->desired_matrix;
+  struct glyph_matrix *current_matrix = f->current_matrix;
+  struct glyph_matrix *desired_matrix = f->desired_matrix;
   struct glyph_row *current_row = MATRIX_ROW (current_matrix, vpos);
   struct glyph_row *desired_row = MATRIX_ROW (desired_matrix, vpos);
   int must_write_whole_line_p;
   int write_spaces_p = must_write_spaces;
-  int colored_spaces_p = (FACE_FROM_ID (frame, DEFAULT_FACE_ID)->background
+  int colored_spaces_p = (FACE_FROM_ID (f, DEFAULT_FACE_ID)->background
                           != FACE_TTY_DEFAULT_BG_COLOR);
 
   if (colored_spaces_p)
@@ -5388,7 +5388,7 @@ update_frame_line (frame, vpos)
           /* For an inverse-video line, make sure it's filled with
              spaces all the way to the frame edge so that the reverse
              video extends all the way across.  */
-          while (olen < FRAME_WIDTH (frame) - 1)
+          while (olen < FRAME_WIDTH (f) - 1)
             obody[olen++] = space_glyph;
         }
     }
@@ -5426,10 +5426,10 @@ update_frame_line (frame, vpos)
       /* Don't call clear_end_of_line if we already wrote the whole
          line.  The cursor will not be at the right margin in that
          case but in the line below.  */
-      if (nlen < FRAME_WINDOW_WIDTH (frame))
+      if (nlen < FRAME_WINDOW_WIDTH (f))
         {
           cursor_to (vpos, nlen);
-          clear_end_of_line (FRAME_WINDOW_WIDTH (frame));
+          clear_end_of_line (FRAME_WINDOW_WIDTH (f));
         }
       else
         /* Make sure we are in the right row, otherwise cursor movement
@@ -5453,7 +5453,7 @@ update_frame_line (frame, vpos)
       /* For an inverse-video line, give it extra trailing spaces all
          the way to the frame edge so that the reverse video extends
          all the way across.  */
-      while (nlen < FRAME_WIDTH (frame) - 1)
+      while (nlen < FRAME_WIDTH (f) - 1)
         nbody[nlen++] = space_glyph;
     }
 
@@ -5563,7 +5563,7 @@ update_frame_line (frame, vpos)
 
   tem = (nlen - nsp) - (olen - osp);
   if (endmatch && tem
-      && (!char_ins_del_ok || endmatch <= char_ins_del_cost (frame)[tem]))
+      && (!char_ins_del_ok || endmatch <= char_ins_del_cost (f)[tem]))
     endmatch = 0;
 
   /* nsp - osp is the distance to insert or delete.
@@ -5573,7 +5573,7 @@ update_frame_line (frame, vpos)
 
   if (nsp != osp
       && (!char_ins_del_ok
-          || begmatch + endmatch <= char_ins_del_cost (frame)[nsp - osp]))
+          || begmatch + endmatch <= char_ins_del_cost (f)[nsp - osp]))
     {
       begmatch = 0;
       endmatch = 0;
@@ -5607,16 +5607,23 @@ update_frame_line (frame, vpos)
   tem = nsp + begmatch + endmatch;
   if (nlen != tem || olen != tem)
     {
-      cursor_to (vpos, nsp + begmatch);
       if (!endmatch || nlen == olen)
         {
-          /* If new text being written reaches right margin,
-             there is no need to do clear-to-eol at the end.
-             (and it would not be safe, since cursor is not
-             going to be "at the margin" after the text is done) */
-          if (nlen == FRAME_WINDOW_WIDTH (frame))
+          /* If new text being written reaches right margin, there is
+             no need to do clear-to-eol at the end of this function
+             (and it would not be safe, since cursor is not going to
+             be "at the margin" after the text is done).  */
+          if (nlen == FRAME_WINDOW_WIDTH (f))
             olen = 0;
-          write_glyphs (nbody + nsp + begmatch, nlen - tem);
+
+          /* Function write_glyphs is prepared to do nothing
+             if passed a length <= 0.  Check it here to avoid
+             unnecessary cursor movement.  */
+          if (nlen - tem > 0)
+            {
+              cursor_to (vpos, nsp + begmatch);
+              write_glyphs (nbody + nsp + begmatch, nlen - tem);
+            }
         }
       else if (nlen > olen)
         {
@@ -5630,18 +5637,25 @@ update_frame_line (frame, vpos)
           int out = olen - tem; /* Columns to be overwritten originally.  */
           int del;
 
+          cursor_to (vpos, nsp + begmatch);
+          
           /* Calculate columns we can actually overwrite.  */
-          while (CHAR_GLYPH_PADDING_P (nbody[nsp + begmatch + out])) out--;
+          while (CHAR_GLYPH_PADDING_P (nbody[nsp + begmatch + out]))
+            out--;
           write_glyphs (nbody + nsp + begmatch, out);
+          
           /* If we left columns to be overwritten, we must delete them.  */
           del = olen - tem - out;
-          if (del > 0) delete_glyphs (del);
+          if (del > 0)
+            delete_glyphs (del);
+          
           /* At last, we insert columns not yet written out.  */
           insert_glyphs (nbody + nsp + begmatch + out, nlen - olen + del);
           olen = nlen;
         }
       else if (olen > nlen)
         {
+          cursor_to (vpos, nsp + begmatch);
           write_glyphs (nbody + nsp + begmatch, nlen - tem);
           delete_glyphs (olen - nlen);
           olen = nlen;