Add capability to decode only a subset of all components of an image.

This adds a opj_set_decoded_components(opj_codec_t *p_codec,
OPJ_UINT32 numcomps, const OPJ_UINT32* comps_indices) function,
and equivalent "opj_decompress -c compno[,compno]*" option.

When specified, neither the MCT transform nor JP2 channel transformations
will be applied.

Tests added for various combinations of whole image vs tiled-based decoding,
full or reduced resolution, use of decode area or not.

1 files changed, 33 insertions, 0 deletions

diff --git a/src/lib/openjp2/openjpeg.c b/src/lib/openjp2/openjpeg.c
index 4e649a74..5ba205e1 100644
--- a/src/lib/openjp2/openjpeg.c
+++ b/src/lib/openjp2/openjpeg.c
@@ -245,6 +245,12 @@ opj_codec_t* OPJ_CALLCONV opj_create_decompress(OPJ_CODEC_FORMAT p_format)
                          OPJ_UINT32 res_factor,
                          struct opj_event_mgr * p_manager)) opj_j2k_set_decoded_resolution_factor;
 
+        l_codec->m_codec_data.m_decompression.opj_set_decoded_components =
+            (OPJ_BOOL(*)(void * p_codec,
+                         OPJ_UINT32 numcomps,
+                         const OPJ_UINT32 * comps_indices,
+                         struct opj_event_mgr * p_manager)) opj_j2k_set_decoded_components;
+
         l_codec->opj_set_threads =
             (OPJ_BOOL(*)(void * p_codec, OPJ_UINT32 num_threads)) opj_j2k_set_threads;
 
@@ -327,6 +333,12 @@ opj_codec_t* OPJ_CALLCONV opj_create_decompress(OPJ_CODEC_FORMAT p_format)
                          OPJ_UINT32 res_factor,
                          opj_event_mgr_t * p_manager)) opj_jp2_set_decoded_resolution_factor;
 
+        l_codec->m_codec_data.m_decompression.opj_set_decoded_components =
+            (OPJ_BOOL(*)(void * p_codec,
+                         OPJ_UINT32 numcomps,
+                         const OPJ_UINT32 * comps_indices,
+                         struct opj_event_mgr * p_manager)) opj_jp2_set_decoded_components;
+
         l_codec->opj_set_threads =
             (OPJ_BOOL(*)(void * p_codec, OPJ_UINT32 num_threads)) opj_jp2_set_threads;
 
@@ -426,6 +438,27 @@ OPJ_BOOL OPJ_CALLCONV opj_read_header(opj_stream_t *p_stream,
     return OPJ_FALSE;
 }
 
+
+OPJ_BOOL OPJ_CALLCONV opj_set_decoded_components(opj_codec_t *p_codec,
+        OPJ_UINT32 numcomps,
+        const OPJ_UINT32* comps_indices)
+{
+    if (p_codec) {
+        opj_codec_private_t * l_codec = (opj_codec_private_t *) p_codec;
+
+        if (! l_codec->is_decompressor) {
+            return OPJ_FALSE;
+        }
+
+        return  l_codec->m_codec_data.m_decompression.opj_set_decoded_components(
+                    l_codec->m_codec,
+                    numcomps,
+                    comps_indices,
+                    &(l_codec->m_event_mgr));
+    }
+    return OPJ_FALSE;
+}
+
 OPJ_BOOL OPJ_CALLCONV opj_decode(opj_codec_t *p_codec,
                                  opj_stream_t *p_stream,
                                  opj_image_t* p_image)