From 3da30304fc1225ab55ab7c5e791870fec1b0b3c3 Mon Sep 17 00:00:00 2001
From: Mathieu Malaterre <mathieu.malaterre@gmail.com>
Date: Wed, 26 Feb 2014 11:03:55 +0000
Subject: [PATCH] [trunk] Import patch from sumatrapdf team. This adds alpha
 handling. This patch changes ABI.

Update issue 225
---
 src/lib/openjp2/jp2.c      | 9 ++++++++-
 src/lib/openjp2/openjpeg.h | 2 ++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/lib/openjp2/jp2.c b/src/lib/openjp2/jp2.c
index d3f7515b..9dde2e97 100644
--- a/src/lib/openjp2/jp2.c
+++ b/src/lib/openjp2/jp2.c
@@ -995,7 +995,12 @@ void opj_jp2_apply_cdef(opj_image_t *image, opj_jp2_color_t *color)
 	for(i = 0; i < n; ++i)
 	{
 		/* WATCH: acn = asoc - 1 ! */
-		if((asoc = info[i].asoc) == 0) continue;
+		if((asoc = info[i].asoc) == 0)
+                {
+                    if (i < image->numcomps)
+                        image->comps[i].alpha = info[i].typ;
+                    continue;
+                }
 
 		cn = info[i].cn; 
         acn = asoc - 1;
@@ -1011,6 +1016,8 @@ void opj_jp2_apply_cdef(opj_image_t *image, opj_jp2_color_t *color)
 			info[i].asoc = cn + 1;
 			info[acn].asoc = info[acn].cn + 1;
 		}
+
+		image->comps[cn].alpha = info[i].typ;
 	}
 
 	if(color->jp2_cdef->info) opj_free(color->jp2_cdef->info);
diff --git a/src/lib/openjp2/openjpeg.h b/src/lib/openjp2/openjpeg.h
index bbc74577..4792433a 100644
--- a/src/lib/openjp2/openjpeg.h
+++ b/src/lib/openjp2/openjpeg.h
@@ -538,6 +538,8 @@ typedef struct opj_image_comp {
 	OPJ_UINT32 factor;
 	/** image component data */
 	OPJ_INT32 *data;
+  /** alpha channel */
+  OPJ_UINT16 alpha;
 } opj_image_comp_t;
 
 /**