From 7f82890157a60bafd2242e2d06f1716c885ef462 Mon Sep 17 00:00:00 2001
From: mounaiban <29518031+mounaiban@users.noreply.github.com>
Date: Tue, 23 Aug 2022 22:52:36 +1000
Subject: [PATCH 1/2] Don't use fprintf() in do_cancel()

fprintf() is not re-entrant
---
 src/rastertocapt.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/src/rastertocapt.c b/src/rastertocapt.c
index 894d523..0711734 100644
--- a/src/rastertocapt.c
+++ b/src/rastertocapt.c
@@ -208,7 +208,6 @@ static void send_page_data(struct printer_state_s *state, const struct cached_pa
 static void do_cancel(int s)
 {
 	(void) s;
-	fprintf(stderr, "DEBUG: CAPT: begin job cancellation cleanup\n");
 
 	if (ops)
 		ops->cancel_cleanup(state);
@@ -228,7 +227,6 @@ static void do_cancel(int s)
 	if (state)
 		free_state();
 
-	fprintf(stderr, "DEBUG: CAPT: job cancellation cleanup complete\n");
 	exit(1);
 }
 

From 104f414d072bcd9c6e0fa7bcc422088a70d19aea Mon Sep 17 00:00:00 2001
From: mounaiban <29518031+mounaiban@users.noreply.github.com>
Date: Wed, 24 Aug 2022 05:10:15 +1000
Subject: [PATCH 2/2] Add manual duplex mode

Printer will wait on user to feed the last printed sheet back into the input tray to print on the other side; press the button to continue
---
 src/canon-lbp.drv  | 6 +++++-
 src/paper.c        | 1 +
 src/paper.h        | 1 +
 src/rastertocapt.c | 4 ++++
 4 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/canon-lbp.drv b/src/canon-lbp.drv
index 40d1641..c14e116 100644
--- a/src/canon-lbp.drv
+++ b/src/canon-lbp.drv
@@ -16,7 +16,7 @@ Copyright "(C)2020 Moses Chong"
 ColorModel "Gray/Grayscale" k chunky 2
 Filter application/vnd.cups-raster 1 rastertocapt
 *Manufacturer "Canon Inc"
-Version 0.1.3
+Version 0.1.4
 {
 	Font *
 
@@ -25,6 +25,10 @@ Version 0.1.3
         *Choice False/Disabled "<</cupsInteger0 0>>setpagedevice"
         Choice True/Enabled    "<</cupsInteger0 1>>setpagedevice"
 
+	Option "captManualDuplex/Manual Duplex" Boolean AnySetup 10
+	*Choice False/Disabled	"<</cupsInteger2 0>>setpagedevice"
+	Choice True/Enabled	"<</cupsInteger2 1>>setpagedevice"
+
 	{
                 *Resolution k 1 70 592 0 "600dpi/600 DPI"
 
diff --git a/src/paper.c b/src/paper.c
index 17dcd9d..dc6b5e6 100644
--- a/src/paper.c
+++ b/src/paper.c
@@ -29,6 +29,7 @@ void page_set_dims(struct page_dims_s *dims, const struct cups_page_header2_s *h
 	dims->paper_height = header->cupsHeight; //header->PageSize[1] * header->HWResolution[1] / 72;
 	dims->toner_save = header->cupsInteger[0];
 	dims->ink_k = header->cupsInteger[1];
+	dims->manual_duplex = header->cupsInteger[2];
 	dims->line_size = header->PageSize[0];
 	dims->num_lines = header->cupsHeight;
 	dims->band_size = header->cupsRowCount;
diff --git a/src/paper.h b/src/paper.h
index 11f558e..2aca392 100644
--- a/src/paper.h
+++ b/src/paper.h
@@ -31,6 +31,7 @@ struct page_dims_s {
 	unsigned paper_width;
 	unsigned paper_height;
 	unsigned toner_save;
+	unsigned manual_duplex;
 	unsigned ink_k;
 	unsigned margin_height;
 	unsigned margin_width;
diff --git a/src/rastertocapt.c b/src/rastertocapt.c
index 0711734..09f890d 100644
--- a/src/rastertocapt.c
+++ b/src/rastertocapt.c
@@ -278,6 +278,10 @@ static void do_print(int fd)
 
 		fprintf(stderr, "DEBUG: CAPT: rastertocapt: start page %u\n", state->ipage);
 		if (ops->page_prologue) {
+			if (cached_page->dims.manual_duplex && state->ipage > 1) {
+				fprintf(stderr, "DEBUG: CAPT: rastertocapt: manual duplex: press button to continue\n");
+				ops->wait_user(state);
+			}
 			bool ok = ops->page_prologue(state, &cached_page->dims);
 			if (! ok) {
 				fprintf(stderr, "DEBUG: CAPT: rastertocapt: can't start page\n");