[evince] [printing] Fix even / odd multipage issues

[Carlos Garcia Campos <carlosgc src gnome org>]

commit ab09124515eeee70ecff9ad920b933c450a9ae09
Author: Bartek Kostrzewa <zoombat runbox com>
Date:   Sun Jul 12 13:24:40 2009 +0200

    [printing] Fix even / odd multipage issues
    
    The patch seems to work alright judging by the test-case, except for printing
    in reverse where it produces blanks (as it inserts blank pages when the last
    "page range to be printed" is reached) Note that if the pages were provided in
    the correct order for multipage reverse printing, it would work properly.
    
    Another (very) minor issue is that if one is printing say a 4-page document
    with 4 pages per sheet and one chooses to print "even sheets only", a blank
    page will be printed. This is a user interface problem as the UI should not
    allow "even sheets" to be selected if there are none. (the same is true if you
    print "even sheets" in a single-page document at one-page per sheet)
    
    See bgo#583429.

 shell/ev-print-operation.c |  114 +++++++++++++++++++++++++++++++++++---------
 1 files changed, 91 insertions(+), 23 deletions(-)
---
diff --git a/shell/ev-print-operation.c b/shell/ev-print-operation.c
index b115887..efb00a9 100644
--- a/shell/ev-print-operation.c
+++ b/shell/ev-print-operation.c
@@ -373,7 +373,9 @@ struct _EvPrintOperationExport {
 	gint n_pages_to_print;
 	gint uncollated_copies;
 	gint collated_copies;
-	gint uncollated, collated, total, blank;
+	gint uncollated, collated, total;
+
+	gint sheet, page_count;
 
 	gint range, n_ranges;
 	GtkPageRange *ranges;
@@ -670,10 +672,40 @@ export_print_inc_page (EvPrintOperationExport *export)
 {
 	do {
 		export->page += export->inc;
+
+		/* note: when NOT collating, page_count is increased in export_print_page */
+		if (export->collate) {
+			export->page_count++;
+			export->sheet = 1 + (export->page_count - 1) / export->pages_per_sheet;
+		}
+
 		if (export->page == export->end) {
 			export->range += export->inc;
 			if (export->range == -1 || export->range == export->n_ranges) {
 				export->uncollated++;
+
+				/* when printing multiple collated copies & multiple pages per sheet we want to
+				 * prevent the next copy bleeding into the last sheet of the previous one
+				 * we've reached the last range to be printed now, so this is the time to do it */
+				if (export->pages_per_sheet > 1 && export->collate == 1 &&
+				    (export->page_count - 1) % export->pages_per_sheet != 0) {
+
+					EvPrintOperation *op = EV_PRINT_OPERATION (export);
+					ev_document_doc_mutex_lock ();
+
+					/* keep track of all blanks but only actualise those
+					 * which are in the current odd / even sheet set */
+
+					export->page_count += export->pages_per_sheet - (export->page_count - 1) % export->pages_per_sheet;
+					if (export->page_set == GTK_PAGE_SET_ALL ||
+						(export->page_set == GTK_PAGE_SET_EVEN && export->sheet % 2 == 0) ||
+						(export->page_set == GTK_PAGE_SET_ODD && export->sheet % 2 == 1) ) {
+						ev_file_exporter_end_page (EV_FILE_EXPORTER (op->document));
+					}
+					ev_document_doc_mutex_unlock ();
+					export->sheet = 1 + (export->page_count - 1) / export->pages_per_sheet;
+				}
+
 				if (export->uncollated == export->uncollated_copies)
 					return FALSE;
 
@@ -682,8 +714,12 @@ export_print_inc_page (EvPrintOperationExport *export)
 			find_range (export);
 			export->page = export->start;
 		}
-	} while ((export->page_set == GTK_PAGE_SET_EVEN && (export->page / export->pages_per_sheet) % 2 == 0) ||
-		 (export->page_set == GTK_PAGE_SET_ODD && (export->page  / export->pages_per_sheet) % 2 == 1));
+
+	/* in/decrement the page number until we reach the first page on the next EVEN or ODD sheet
+	 * if we're not collating, we have to make sure that this is done only once! */
+	} while ( export->collate == 1 &&
+		((export->page_set == GTK_PAGE_SET_EVEN && export->sheet % 2 == 1) ||
+		(export->page_set == GTK_PAGE_SET_ODD && export->sheet % 2 == 0)));
 
 	return TRUE;
 }
@@ -881,7 +917,12 @@ export_job_finished (EvJobExport            *job,
 {
 	EvPrintOperation *op = EV_PRINT_OPERATION (export);
 
-	if (export->pages_per_sheet == 1 || (export->total + export->blank) % export->pages_per_sheet == 0 ) {
+	if (export->pages_per_sheet == 1 ||
+	   ( export->page_count % export->pages_per_sheet == 0 &&
+	   ( export->page_set == GTK_PAGE_SET_ALL ||
+	   ( export->page_set == GTK_PAGE_SET_EVEN && export->sheet % 2 == 0 ) ||
+	   ( export->page_set == GTK_PAGE_SET_ODD && export->sheet % 2 == 1 ) ) ) ) {
+
 		ev_document_doc_mutex_lock ();
 		ev_file_exporter_end_page (EV_FILE_EXPORTER (op->document));
 		ev_document_doc_mutex_unlock ();
@@ -950,28 +991,16 @@ export_print_page (EvPrintOperationExport *export)
 
 	if (!export->temp_file)
 		return FALSE; /* cancelled */
-	
+
 	export->total++;
 	export->collated++;
 
-	/* when printing multiple collated copies & multiple pages per sheet we want to
-	   prevent the next copy bleeding into the last sheet of the previous one
-	   we therefore check whether we've reached the last page in a document
-	   if that is the case and the given sheet is not filled with pages,
-	   we introduce a few blank pages to finish off the sheet
-	   to make sure nothing goes wrong, the final condition ensures that
-	   we're not at the end of a sheet, otherwise we'd introduce a blank sheet! */
-
-	if (export->collate == 1 && export->total > 1 && export->pages_per_sheet > 1 &&
-	    (export->page + 1) % export->n_pages == 0 && (export->total - 1 + export->blank) % export->pages_per_sheet != 0) {
-		ev_document_doc_mutex_lock ();
-		ev_file_exporter_end_page (EV_FILE_EXPORTER (op->document));
-		/* keep track of how many blank pages have been added */
-		export->blank += export->pages_per_sheet - (export->total - 1 + export->blank) % export->pages_per_sheet;
-		ev_document_doc_mutex_unlock ();
+	/* note: when collating, page_count is increased in export_print_inc_page */
+	if (!export->collate) {
+		export->page_count++;
+		export->sheet = 1 + (export->page_count - 1) / export->pages_per_sheet;
 	}
 
-
 	if (export->collated == export->collated_copies) {
 		export->collated = 0;
 		if (!export_print_inc_page (export)) {
@@ -988,12 +1017,49 @@ export_print_page (EvPrintOperationExport *export)
 		}
 	}
 
-	if (export->pages_per_sheet == 1 || (export->total + export->blank) % export->pages_per_sheet == 1) {
+	/* we're not collating and we've reached a sheet from the wrong sheet set */
+	if (!export->collate &&
+	    ((export->page_set == GTK_PAGE_SET_EVEN && export->sheet % 2 != 0) ||
+	    (export->page_set == GTK_PAGE_SET_ODD && export->sheet % 2 != 1))) {
+
+		do {
+			export->page_count++;
+			export->collated++;
+			export->sheet = 1 + (export->page_count - 1) / export->pages_per_sheet;
+
+			if (export->collated == export->collated_copies) {
+				export->collated = 0;
+
+				if (!export_print_inc_page (export)) {
+					ev_document_doc_mutex_lock ();
+					ev_file_exporter_end (EV_FILE_EXPORTER (op->document));
+					ev_document_doc_mutex_unlock ();
+
+					close (export->fd);
+					export->fd = -1;
+
+					update_progress (export);
+
+					export_print_done (export);
+					return FALSE;
+				}
+			}
+
+		} while ((export->page_set == GTK_PAGE_SET_EVEN && export->sheet % 2 != 0) ||
+	    		  (export->page_set == GTK_PAGE_SET_ODD && export->sheet % 2 != 1));
+
+	}
+
+	if (export->pages_per_sheet == 1 ||
+	    (export->page_count % export->pages_per_sheet == 1 &&
+	    (export->page_set == GTK_PAGE_SET_ALL ||
+	    (export->page_set == GTK_PAGE_SET_EVEN && export->sheet % 2 == 0) ||
+	    (export->page_set == GTK_PAGE_SET_ODD && export->sheet % 2 == 1)))) {
 		ev_document_doc_mutex_lock ();
 		ev_file_exporter_begin_page (EV_FILE_EXPORTER (op->document));
 		ev_document_doc_mutex_unlock ();
 	}
-	
+
 	if (!export->job_export) {
 		export->job_export = ev_job_export_new (op->document);
 		g_signal_connect (export->job_export, "finished",
@@ -1344,6 +1410,8 @@ ev_print_operation_export_finalize (GObject *object)
 static void
 ev_print_operation_export_init (EvPrintOperationExport *export)
 {
+	/* sheets are counted from 1 to be physical */
+	export->sheet = 1;
 }
 
 static GObject *