From cf5153c518045027f286e08af36809237a76a7df Mon Sep 17 00:00:00 2001
From: Antonin Descampe <antonin@gmail.com>
Date: Mon, 3 Nov 2014 14:12:01 +0000
Subject: [PATCH] [trunk] add a cdef box when alpha component is present (fixes
 issue 416)

---
 src/bin/jp2/convert.c |   5 +-
 src/lib/openjp2/jp2.c | 143 +++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 144 insertions(+), 4 deletions(-)

diff --git a/src/bin/jp2/convert.c b/src/bin/jp2/convert.c
index 606238d1..6af7b7ab 100644
--- a/src/bin/jp2/convert.c
+++ b/src/bin/jp2/convert.c
@@ -3364,7 +3364,10 @@ opj_image_t *pngtoimage(const char *read_idf, opj_cparameters_t * params)
     r = image->comps[0].data;
     g = image->comps[1].data;
     b = image->comps[2].data;
-    if(has_alpha) a = image->comps[3].data;
+    if(has_alpha) {
+        a = image->comps[3].data;
+        image->comps[3].alpha = 1;
+    }
 
     for(i = 0; i < height; ++i)
     {
diff --git a/src/lib/openjp2/jp2.c b/src/lib/openjp2/jp2.c
index bce8813c..219278fe 100644
--- a/src/lib/openjp2/jp2.c
+++ b/src/lib/openjp2/jp2.c
@@ -108,6 +108,17 @@ static OPJ_BOOL opj_jp2_read_cdef(	opj_jp2_t * jp2,
 
 static void opj_jp2_apply_cdef(opj_image_t *image, opj_jp2_color_t *color);
 
+/**
+ * Writes the Channel Definition box.
+ *
+ * @param jp2					jpeg2000 file codec.
+ * @param p_nb_bytes_written	pointer to store the nb of bytes written by the function.
+ *
+ * @return	the data being copied.
+ */
+static OPJ_BYTE * opj_jp2_write_cdef(   opj_jp2_t *jp2,
+																		 OPJ_UINT32 * p_nb_bytes_written );
+
 /**
  * Writes the Colour Specification box.
  *
@@ -680,6 +691,55 @@ OPJ_BOOL opj_jp2_read_bpcc( opj_jp2_t *jp2,
 
 	return OPJ_TRUE;
 }
+static OPJ_BYTE * opj_jp2_write_cdef(opj_jp2_t *jp2, OPJ_UINT32 * p_nb_bytes_written)
+{
+	/* room for 8 bytes for box, 2 for n */
+	OPJ_UINT32 l_cdef_size = 10;
+	OPJ_BYTE * l_cdef_data,* l_current_cdef_ptr;
+	OPJ_UINT32 l_value;
+	OPJ_UINT16 i;
+
+	/* preconditions */
+	assert(jp2 != 00);
+	assert(p_nb_bytes_written != 00);
+	assert(jp2->color.jp2_cdef != 00);
+	assert(jp2->color.jp2_cdef->info != 00);
+	assert(jp2->color.jp2_cdef->n > 0U);
+
+	l_cdef_size += 6 * jp2->color.jp2_cdef->n;
+
+	l_cdef_data = (OPJ_BYTE *) opj_malloc(l_cdef_size);
+	if (l_cdef_data == 00) {
+		return 00;
+	}
+
+	l_current_cdef_ptr = l_cdef_data;
+	
+	opj_write_bytes(l_current_cdef_ptr,l_cdef_size,4);			/* write box size */
+	l_current_cdef_ptr += 4;
+
+	opj_write_bytes(l_current_cdef_ptr,JP2_CDEF,4);					/* BPCC */
+	l_current_cdef_ptr += 4;
+
+	l_value = jp2->color.jp2_cdef->n;
+	opj_write_bytes(l_current_cdef_ptr,l_value,2);					/* N */
+	l_current_cdef_ptr += 2;
+
+	for (i = 0U; i < jp2->color.jp2_cdef->n; ++i) {
+		l_value = jp2->color.jp2_cdef->info[i].cn;
+		opj_write_bytes(l_current_cdef_ptr,l_value,2);					/* Cni */
+		l_current_cdef_ptr += 2;
+		l_value = jp2->color.jp2_cdef->info[i].typ;
+		opj_write_bytes(l_current_cdef_ptr,l_value,2);					/* Typi */
+		l_current_cdef_ptr += 2;
+		l_value = jp2->color.jp2_cdef->info[i].asoc;
+		opj_write_bytes(l_current_cdef_ptr,l_value,2);					/* Asoci */
+		l_current_cdef_ptr += 2;
+	}
+	*p_nb_bytes_written = l_cdef_size;
+
+	return l_cdef_data;
+}
 
 OPJ_BYTE * opj_jp2_write_colr(  opj_jp2_t *jp2,
 							    OPJ_UINT32 * p_nb_bytes_written
@@ -688,7 +748,7 @@ OPJ_BYTE * opj_jp2_write_colr(  opj_jp2_t *jp2,
 	/* room for 8 bytes for box 3 for common data and variable upon profile*/
 	OPJ_UINT32 l_colr_size = 11;
 	OPJ_BYTE * l_colr_data,* l_current_colr_ptr;
-	
+
 	/* preconditions */
 	assert(jp2 != 00);
 	assert(p_nb_bytes_written != 00);
@@ -1385,7 +1445,7 @@ OPJ_BOOL opj_jp2_write_jp2h(opj_jp2_t *jp2,
                             opj_event_mgr_t * p_manager
                             )
 {
-	opj_jp2_img_header_writer_handler_t l_writers [3];
+	opj_jp2_img_header_writer_handler_t l_writers [4];
 	opj_jp2_img_header_writer_handler_t * l_current_writer;
 
 	OPJ_INT32 i, l_nb_pass;
@@ -1415,6 +1475,11 @@ OPJ_BOOL opj_jp2_write_jp2h(opj_jp2_t *jp2,
 		l_writers[1].handler = opj_jp2_write_colr;
 	}
 	
+	if (jp2->color.jp2_cdef != NULL) {
+		l_writers[l_nb_pass].handler = opj_jp2_write_cdef;
+		l_nb_pass++;
+	}
+	
 	/* write box header */
 	/* write JP2H type */
 	opj_write_bytes(l_jp2h_data+4,JP2_JP2H,4);
@@ -1614,9 +1679,13 @@ OPJ_BOOL opj_jp2_setup_encoder(	opj_jp2_t *jp2,
                             opj_image_t *image,
                             opj_event_mgr_t * p_manager)
 {
-    OPJ_UINT32 i;
+	OPJ_UINT32 i;
 	OPJ_UINT32 depth_0;
   OPJ_UINT32 sign;
+	OPJ_UINT32 alpha_count;
+	OPJ_UINT32 color_channels;
+	OPJ_UINT32 alpha_channel;
+	
 
 	if(!jp2 || !parameters || !image)
 		return OPJ_FALSE;
@@ -1697,6 +1766,74 @@ OPJ_BOOL opj_jp2_setup_encoder(	opj_jp2_t *jp2,
             jp2->enumcs = 18;	/* YUV */
     }
 
+	/* Channel Definition box */
+	/* FIXME not provided by parameters */
+	/* We try to do what we can... */
+	alpha_count = 0U;
+	for (i = 0; i < image->numcomps; i++) {
+		if (image->comps[i].alpha != 0) {
+			alpha_count++;
+			alpha_channel = i;
+		}
+	}
+	if (alpha_count == 1U) { /* no way to deal with more than 1 alpha channel */
+		switch (jp2->enumcs) {
+			case 16:
+			case 18:
+				color_channels = 3;
+				break;
+			case 17:
+				color_channels = 1;
+				break;
+			default:
+				alpha_count = 0U;
+				break;
+		}
+		if (alpha_count == 0U) {
+			opj_event_msg(p_manager, EVT_WARNING, "Alpha channel specified but unknown enumcs. No cdef box will be created.\n");
+		} else if (image->numcomps < (color_channels+1)) {
+			opj_event_msg(p_manager, EVT_WARNING, "Alpha channel specified but not enough image components for an automatic cdef box creation.\n");
+			alpha_count = 0U;
+		} else if ((OPJ_UINT32)alpha_channel < color_channels) {
+			opj_event_msg(p_manager, EVT_WARNING, "Alpha channel position conflicts with color channel. No cdef box will be created.\n");
+			alpha_count = 0U;
+		}
+	} else if (alpha_count > 1) {
+		opj_event_msg(p_manager, EVT_WARNING, "Multiple alpha channels specified. No cdef box will be created.\n");
+	}
+	if (alpha_count == 1U) { /* if here, we know what we can do */
+		jp2->color.jp2_cdef = (opj_jp2_cdef_t*)opj_malloc(sizeof(opj_jp2_cdef_t));
+		if(!jp2->color.jp2_cdef) {
+			opj_event_msg(p_manager, EVT_ERROR, "Not enough memory to setup the JP2 encoder\n");
+			return OPJ_FALSE;
+		}
+		/* no memset needed, all values will be overwritten except if jp2->color.jp2_cdef->info allocation fails, */
+		/* in which case jp2->color.jp2_cdef->info will be NULL => valid for destruction */
+		jp2->color.jp2_cdef->info = (opj_jp2_cdef_info_t*) opj_malloc(image->numcomps * sizeof(opj_jp2_cdef_info_t));
+		if (!jp2->color.jp2_cdef->info) {
+			/* memory will be freed by opj_jp2_destroy */
+			opj_event_msg(p_manager, EVT_ERROR, "Not enough memory to setup the JP2 encoder\n");
+			return OPJ_FALSE;
+		}
+		jp2->color.jp2_cdef->n = (OPJ_UINT16) image->numcomps; /* cast is valid : image->numcomps [1,16384] */
+		for (i = 0U; i < color_channels; i++) {
+			jp2->color.jp2_cdef->info[i].cn = (OPJ_UINT16)i; /* cast is valid : image->numcomps [1,16384] */
+			jp2->color.jp2_cdef->info[i].typ = 0U;
+			jp2->color.jp2_cdef->info[i].asoc = (OPJ_UINT16)(i+1U); /* No overflow + cast is valid : image->numcomps [1,16384] */
+		}
+		for (; i < image->numcomps; i++) {
+			if (image->comps[i].alpha != 0) { /* we'll be here exactly once */
+				jp2->color.jp2_cdef->info[i].cn = (OPJ_UINT16)i; /* cast is valid : image->numcomps [1,16384] */
+				jp2->color.jp2_cdef->info[i].typ = 1U; /* Opacity channel */
+				jp2->color.jp2_cdef->info[i].asoc = 0U; /* Apply alpha channel to the whole image */
+			} else {
+				/* Unknown channel */
+				jp2->color.jp2_cdef->info[i].cn = (OPJ_UINT16)i; /* cast is valid : image->numcomps [1,16384] */
+				jp2->color.jp2_cdef->info[i].typ = 65535U;
+				jp2->color.jp2_cdef->info[i].asoc = 65535U;
+			}
+		}
+	}
 
 	jp2->precedence = 0;	/* PRECEDENCE */
 	jp2->approx = 0;		/* APPROX */