Fix bug #16806 with horizontal scrolling of images when fringes are disabled.

 src/xdisp.c (display_line): Fix horizontal scrolling of large images
 when fringes are turned off.  This comes at a price of not
 displaying the truncation/continuation glyphs in this case.

2 files changed, 33 insertions, 13 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index cbc48a75469..f89f7e084ff 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,10 @@
 2014-02-19  Eli Zaretskii  <eliz@gnu.org>
 
+        * xdisp.c (display_line): Fix horizontal scrolling of large images
+        when fringes are turned off.  This comes at a price of not
+        displaying the truncation/continuation glyphs in this case.
+        (Bug#16806)
+
         * image.c (x_create_x_image_and_pixmap) [HAVE_NTGUI]: If
         CreateDIBSection returns an error indication, zero out *ximg after
         destroying the image.  This avoids crashes in memory allocations
diff --git a/src/xdisp.c b/src/xdisp.c
index d941c7b1086..b9908c6c9c6 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -20119,7 +20119,12 @@ display_line (struct it *it)
       /* If we truncate lines, we are done when the last displayed
          glyphs reach past the right margin of the window.  */
       if (it->line_wrap == TRUNCATE
-          && (FRAME_WINDOW_P (it->f) && WINDOW_RIGHT_FRINGE_WIDTH (it->w)
+          && ((FRAME_WINDOW_P (it->f)
+               /* Images are preprocessed in produce_image_glyph such
+                  that they are cropped at the right edge of the
+                  window, so an image glyph will always end exactly at
+                  last_visible_x, even if there's no right fringe.  */
+               && (WINDOW_RIGHT_FRINGE_WIDTH (it->w) || it->what == IT_IMAGE))
               ? (it->current_x >= it->last_visible_x)
               : (it->current_x > it->last_visible_x)))
         {
@@ -20152,19 +20157,26 @@ display_line (struct it *it)
                   i = row->used[TEXT_AREA] - (i + 1);
                 }
 
-              it->current_x = x_before;
-              if (!FRAME_WINDOW_P (it->f))
+              /* produce_special_glyphs overwrites the last glyph, so
+                 we don't want that if we want to keep that last
+                 glyph, which means it's an image.  */
+              if (it->current_x > it->last_visible_x)
                 {
-                  for (n = row->used[TEXT_AREA]; i < n; ++i)
+                  it->current_x = x_before;
+                  if (!FRAME_WINDOW_P (it->f))
+                    {
+                      for (n = row->used[TEXT_AREA]; i < n; ++i)
+                        {
+                          row->used[TEXT_AREA] = i;
+                          produce_special_glyphs (it, IT_TRUNCATION);
+                        }
+                    }
+                  else
                     {
                       row->used[TEXT_AREA] = i;
                       produce_special_glyphs (it, IT_TRUNCATION);
                     }
-                }
-              else
-                {
-                  row->used[TEXT_AREA] = i;
-                  produce_special_glyphs (it, IT_TRUNCATION);
+                  it->hpos = hpos_before;
                 }
             }
           else if (IT_OVERFLOW_NEWLINE_INTO_FRINGE (it))
@@ -20183,13 +20195,13 @@ display_line (struct it *it)
                   goto at_end_of_line;
                 }
               it->current_x = x_before;
+              it->hpos = hpos_before;
             }
 
           row->truncated_on_right_p = 1;
           it->continuation_lines_width = 0;
           reseat_at_next_visible_line_start (it, 0);
           row->ends_at_zv_p = FETCH_BYTE (IT_BYTEPOS (*it) - 1) != '\n';
-          it->hpos = hpos_before;
           break;
         }
     }
@@ -20203,9 +20215,12 @@ display_line (struct it *it)
       && IT_CHARPOS (*it) != CHARPOS (row->start.pos))
     {
       if (!FRAME_WINDOW_P (it->f)
-          || (row->reversed_p
-              ? WINDOW_RIGHT_FRINGE_WIDTH (it->w)
-              : WINDOW_LEFT_FRINGE_WIDTH (it->w)) == 0)
+          || (((row->reversed_p
+                ? WINDOW_RIGHT_FRINGE_WIDTH (it->w)
+                : WINDOW_LEFT_FRINGE_WIDTH (it->w)) == 0)
+              /* Don't let insert_left_trunc_glyphs overwrite the
+                 first glyph of the row if it is an image.  */
+              && row->glyphs[TEXT_AREA]->type != IMAGE_GLYPH))
         insert_left_trunc_glyphs (it);
       row->truncated_on_left_p = 1;
     }