[vte/vte-0-34] Bug 415277 - Garbage displayed after resizing whilst using an alternate screen

[Behdad Esfahbod <behdad src gnome org>]

commit 6b022a603c0c582a3673e0f883366532effc784b
Author: Behdad Esfahbod <behdad behdad org>
Date:   Sun Sep 29 15:58:44 2013 -0400

    Bug 415277 - Garbage displayed after resizing whilst using an alternate screen
    
    Patch from Egmont Koblinger.

 src/vte.c |  140 +++++++++++++++++++++++++++++++++++--------------------------
 1 files changed, 80 insertions(+), 60 deletions(-)
---
diff --git a/src/vte.c b/src/vte.c
index 7f78450..fa1c417 100644
--- a/src/vte.c
+++ b/src/vte.c
@@ -8011,6 +8011,82 @@ vte_terminal_refresh_size(VteTerminal *terminal)
        }
 }
 
+/* Resize the given screen (normal or alternate) of the terminal. */
+static void
+vte_terminal_screen_set_size(VteTerminal *terminal, VteScreen *screen, glong old_columns, glong old_rows)
+{
+       VteRing *ring = screen->row_data;
+       gboolean was_scrolled_to_top = (screen->scroll_delta == _vte_ring_delta(ring));
+       gboolean was_scrolled_to_bottom = (screen->scroll_delta == screen->insert_delta);
+       glong new_scroll_delta;
+       long cursor_saved_absolute_row = screen->insert_delta + screen->cursor_saved.row;
+
+       _vte_debug_print(VTE_DEBUG_RESIZE,
+                       "Resizing %s screen\n"
+                       "Old  ring_delta=%ld  ring_next=%ld\n"
+                       "Old  insert_delta=%ld  scroll_delta=%ld\n",
+                       screen == &terminal->pvt->normal_screen ? "normal" : "alternate",
+                       _vte_ring_delta(ring), _vte_ring_next(ring),
+                       screen->insert_delta, screen->scroll_delta);
+
+       if (old_rows > terminal->row_count &&
+           screen->insert_delta + old_rows > screen->cursor_current.row + 1) {
+               /* Shrinking the window, cursor was not at the bottom.
+                  Drop lines from the bottom as XTerm does, see bug 708213 */
+               int drop_lines = MIN(
+                               old_rows - terminal->row_count,
+                               (screen->insert_delta + old_rows) - (screen->cursor_current.row + 1));
+               int new_ring_next = screen->insert_delta + old_rows - drop_lines;
+               _vte_debug_print(VTE_DEBUG_RESIZE,
+                               "Dropping %d rows at the bottom\n",
+                               drop_lines);
+               _vte_ring_shrink(ring, new_ring_next - _vte_ring_delta(ring));
+       }
+       if (_vte_ring_length(ring) <= terminal->row_count) {
+               /* Everything fits without scrollbars. Align at top. */
+               screen->insert_delta = _vte_ring_delta(ring);
+               new_scroll_delta = screen->insert_delta;
+               _vte_debug_print(VTE_DEBUG_RESIZE,
+                               "Everything fits without scrollbars\n");
+       } else {
+               /* Scrollbar required. Can't afford unused lines at bottom. */
+               screen->insert_delta = _vte_ring_next(ring) - terminal->row_count;
+               if (was_scrolled_to_bottom) {
+                       /* Was scrolled to bottom, keep this way. */
+                       new_scroll_delta = screen->insert_delta;
+                       _vte_debug_print(VTE_DEBUG_RESIZE,
+                                       "Scroll to bottom\n");
+               } else if (was_scrolled_to_top) {
+                       /* Was scrolled to top, keep this way. Not sure if this special case is worth it. */
+                       new_scroll_delta = _vte_ring_delta(ring);
+                       _vte_debug_print(VTE_DEBUG_RESIZE,
+                                       "Scroll to top\n");
+               } else {
+                       /* Try to scroll so that the bottom visible row stays. */
+                       new_scroll_delta = screen->scroll_delta + old_rows - terminal->row_count;
+                       _vte_debug_print(VTE_DEBUG_RESIZE,
+                                       "Scroll so bottom row stays\n");
+               }
+       }
+
+       /* Saved cursor is relative to visible part. Adjust so that it stays relative to the ring.
+          Don't clamp yet (so that it's tracked correctly through multiple resizes), it will be clamped when 
restored. */
+       screen->cursor_saved.row = cursor_saved_absolute_row - screen->insert_delta;
+
+       _vte_debug_print(VTE_DEBUG_RESIZE,
+                       "New  ring_delta=%ld  ring_next=%ld\n"
+                       "New  insert_delta=%ld  scroll_delta=%ld\n\n",
+                       _vte_ring_delta(ring), _vte_ring_next(ring),
+                       screen->insert_delta, new_scroll_delta);
+
+       if (screen == terminal->pvt->screen)
+               vte_terminal_queue_adjustment_value_changed (
+                               terminal,
+                               new_scroll_delta);
+       else
+               screen->scroll_delta = new_scroll_delta;
+}
+
 /**
  * vte_terminal_set_size:
  * @terminal: a #VteTerminal
@@ -8050,67 +8126,11 @@ vte_terminal_set_size(VteTerminal *terminal, glong columns, glong rows)
                terminal->column_count = columns;
        }
        if (old_rows != terminal->row_count || old_columns != terminal->column_count) {
-               VteScreen *screen = terminal->pvt->screen;
-               VteRing *ring = screen->row_data;
-               gboolean was_scrolled_to_top = (screen->scroll_delta == _vte_ring_delta(ring));
-               gboolean was_scrolled_to_bottom = (screen->scroll_delta == screen->insert_delta);
-               glong new_scroll_delta;
-
-               _vte_debug_print(VTE_DEBUG_RESIZE,
-                               "Old  ring_delta=%ld  ring_next=%ld\n"
-                               "Old  insert_delta=%ld  scroll_delta=%ld\n",
-                               _vte_ring_delta(ring), _vte_ring_next(ring),
-                               screen->insert_delta, screen->scroll_delta);
-
-               if (old_rows > terminal->row_count &&
-                   screen->insert_delta + old_rows > screen->cursor_current.row + 1) {
-                       /* Shrinking the window, cursor was not at the bottom.
-                          Drop lines from the bottom as XTerm does, see bug 708213 */
-                       int drop_lines = MIN(
-                                       old_rows - terminal->row_count,
-                                       (screen->insert_delta + old_rows) - (screen->cursor_current.row + 1));
-                       int new_ring_next = screen->insert_delta + old_rows - drop_lines;
-                       _vte_debug_print(VTE_DEBUG_RESIZE,
-                                       "Dropping %d rows at the bottom\n",
-                                       drop_lines);
-                       _vte_ring_shrink(ring, new_ring_next - _vte_ring_delta(ring));
-               }
-               if (_vte_ring_length(ring) <= terminal->row_count) {
-                       /* Everything fits without scrollbars. Align at top. */
-                       screen->insert_delta = _vte_ring_delta(ring);
-                       new_scroll_delta = screen->insert_delta;
-                       _vte_debug_print(VTE_DEBUG_RESIZE,
-                                       "Everything fits without scrollbars\n");
-               } else {
-                       /* Scrollbar required. Can't afford unused lines at bottom. */
-                       screen->insert_delta = _vte_ring_next(ring) - terminal->row_count;
-                       if (was_scrolled_to_bottom) {
-                               /* Was scrolled to bottom, keep this way. */
-                               new_scroll_delta = screen->insert_delta;
-                               _vte_debug_print(VTE_DEBUG_RESIZE,
-                                               "Scroll to bottom\n");
-                       } else if (was_scrolled_to_top) {
-                               /* Was scrolled to top, keep this way. Not sure if this special case is worth 
it. */
-                               new_scroll_delta = _vte_ring_delta(ring);
-                               _vte_debug_print(VTE_DEBUG_RESIZE,
-                                               "Scroll to top\n");
-                       } else {
-                               /* Try to scroll so that the bottom visible row stays. */
-                               new_scroll_delta = screen->scroll_delta + old_rows - terminal->row_count;
-                               _vte_debug_print(VTE_DEBUG_RESIZE,
-                                               "Scroll so bottom row stays\n");
-                       }
-               }
+               /* Always resize normal screen, even if alternate is visible: bug 415277 */
+               vte_terminal_screen_set_size(terminal, &terminal->pvt->normal_screen, old_columns, old_rows);
+               if (terminal->pvt->screen == &terminal->pvt->alternate_screen)
+                       vte_terminal_screen_set_size(terminal, &terminal->pvt->alternate_screen, old_columns, 
old_rows);
 
-               _vte_debug_print(VTE_DEBUG_RESIZE,
-                               "New  ring_delta=%ld  ring_next=%ld\n"
-                               "New  insert_delta=%ld  scroll_delta=%ld\n\n",
-                               _vte_ring_delta(ring), _vte_ring_next(ring),
-                               screen->insert_delta, new_scroll_delta);
-
-               vte_terminal_queue_adjustment_value_changed (
-                               terminal,
-                               new_scroll_delta);
                gtk_widget_queue_resize_no_redraw (&terminal->widget);
                /* Our visible text changed. */
                vte_terminal_emit_text_modified(terminal);