[evince] libview: dual page option is ignored for single page documents

[Germán Poo-Caamaño <gpoo src gnome org>]

commit 0c3cd02db3946bbe648bc18dc7bd10c0bfebff47
Author: Raghuveer Kasaraneni <raghu kasara net>
Date:   Wed Jun 9 04:26:25 2021 +0000

    libview: dual page option is ignored for single page documents
    
    The dual page setting doesn't make sense when the document contains
    only one page. With this change, dual page setting is ignored for
    displaying single page documents.
    
    Closes #220

 libview/ev-view.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/libview/ev-view.c b/libview/ev-view.c
index dab6a7ae..f9281a11 100644
--- a/libview/ev-view.c
+++ b/libview/ev-view.c
@@ -566,7 +566,8 @@ is_dual_page (EvView   *view,
                break;
        case EV_PAGE_LAYOUT_DUAL:
                odd_left = !view->dual_even_left;
-               dual = TRUE;
+               if (ev_document_get_n_pages (view->document) > 1)
+                       dual = TRUE;
                break;
        case EV_PAGE_LAYOUT_SINGLE:
                break;