GUACAMOLE-2158: Merge fix issues on terminal resize.

Author: necouchman

src/terminal/buffer.c

@@ -427,16 +427,20 @@ void guac_terminal_buffer_copy_rows(guac_terminal_buffer* buffer,
 
 }
 
-void guac_terminal_buffer_scroll_up(guac_terminal_buffer* buffer, int amount) {
+void guac_terminal_buffer_scroll_up(guac_terminal_buffer* buffer, int amount,
+        bool increase_length) {
 
     if (amount <= 0)
         return;
 
     buffer->top = (buffer->top + amount) % buffer->available;
 
-    buffer->length += amount;
-    if (buffer->length > buffer->available)
-        buffer->length = buffer->available;
+    /* Increase buffer length only if new row is added */
+    if (increase_length) {
+        buffer->length += amount;
+        if (buffer->length > buffer->available)
+            buffer->length = buffer->available;
+    }
 
 }
 

src/terminal/terminal.c

@@ -834,8 +834,8 @@ void guac_terminal_scroll_up(guac_terminal* term,
         /* Scroll up visibly */
         guac_terminal_display_copy_rows(term->display, start_row + amount, end_row, -amount);
 
-        /* Advance by scroll amount */
-        guac_terminal_buffer_scroll_up(term->current_buffer, amount);
+        /* Advance and increase buffer length by scroll amount */
+        guac_terminal_buffer_scroll_up(term->current_buffer, amount, true);
 
         /* Reset scrollbar bounds */
         guac_terminal_scrollbar_set_bounds(term->scrollbar,
@@ -1225,7 +1225,7 @@ static void __guac_terminal_resize(guac_terminal* term, int width, int height) {
                     shift_amount, term->display->height - 1, -shift_amount);
 
             /* Update buffer top and cursor row based on shift */
-            guac_terminal_buffer_scroll_up(term->current_buffer, shift_amount);
+            guac_terminal_buffer_scroll_up(term->current_buffer, shift_amount, false);
             term->cursor_row  -= shift_amount;
             if (term->visible_cursor_row != -1)
                 term->visible_cursor_row -= shift_amount;
@@ -1296,6 +1296,10 @@ static void __guac_terminal_resize(guac_terminal* term, int width, int height) {
                     /* Draw characters at top from scroll */
                     __guac_terminal_redraw_rect(term, 0, 0, shift_amount - 1, width-1);
 
+                    /* Draw characters from scroll at bottom */
+                    __guac_terminal_redraw_rect(term, term->display->height - shift_amount,
+                            0, term->display->height - 1, width-1);
+
                 }
 
             }

src/terminal/terminal/buffer.h

@@ -91,8 +91,13 @@ void guac_terminal_buffer_copy_rows(guac_terminal_buffer* buffer,
  * @param amount
  *     The number of rows to scroll upwards. Zero and negative values have no
  *     effect.
+ *
+ * @param increase_length
+ *     Whether the length of the buffer should be increased to account for
+ *     newly added rows. If false, the length of the buffer remains unchanged.
  */
-void guac_terminal_buffer_scroll_up(guac_terminal_buffer* buffer, int amount);
+void guac_terminal_buffer_scroll_up(guac_terminal_buffer* buffer, int amount,
+        bool increase_length);
 
 /**
  * Scrolls the contents of the given buffer down by the given number of rows.