== Sequencer ==

Fixes Fix for [#25713] VSE shows and renders wrong straight alpha gradient even after convert to pr
(see revision: 34540, fix by Janne)

By not breaking the seqcache interface API.

Added comments to header file, so that it is easier to understand, how the
cache API is supposed to work.

3 files changed, 26 insertions, 12 deletions

diff --git a/source/blender/blenkernel/BKE_sequencer.h b/source/blender/blenkernel/BKE_sequencer.h
index 33bff1cd6a7..42786e1c9be 100644
--- a/source/blender/blenkernel/BKE_sequencer.h
+++ b/source/blender/blenkernel/BKE_sequencer.h
@@ -217,9 +217,16 @@ void seq_stripelem_cache_destruct(void);
 
 void seq_stripelem_cache_cleanup(void);
 
+/* returned ImBuf is properly refed and has to be freed */
 struct ImBuf * seq_stripelem_cache_get(
 	SeqRenderData context, struct Sequence * seq, 
 	float cfra, seq_stripelem_ibuf_t type);
+
+/* passed ImBuf is properly refed, so ownership is *not* 
+   transfered to the cache.
+   you can pass the same ImBuf multiple times to the cache without problems.
+*/
+   
 void seq_stripelem_cache_put(
 	SeqRenderData context, struct Sequence * seq, 
 	float cfra, seq_stripelem_ibuf_t type, struct ImBuf * nval);
diff --git a/source/blender/blenkernel/intern/seqcache.c b/source/blender/blenkernel/intern/seqcache.c
index e698402c538..00f88fb6202 100644
--- a/source/blender/blenkernel/intern/seqcache.c
+++ b/source/blender/blenkernel/intern/seqcache.c
@@ -237,9 +237,7 @@ void seq_stripelem_cache_put(
 	key->cfra = cfra - seq->start;
 	key->type = type;
 
-	/* Normally we want our own version, but start and end stills are duplicates of the original. */
-	if(ELEM(type, SEQ_STRIPELEM_IBUF_STARTSTILL, SEQ_STRIPELEM_IBUF_ENDSTILL)==0)
-		IMB_refImBuf(i);
+	IMB_refImBuf(i);
 
 	e = (seqCacheEntry*) BLI_mempool_alloc(entrypool);
 
diff --git a/source/blender/blenkernel/intern/sequencer.c b/source/blender/blenkernel/intern/sequencer.c
index 7a6eb1adc9f..a765c9ee8f0 100644
--- a/source/blender/blenkernel/intern/sequencer.c
+++ b/source/blender/blenkernel/intern/sequencer.c
@@ -1720,16 +1720,25 @@ static ImBuf * copy_from_ibuf_still(SeqRenderData context, Sequence * seq,
 static void copy_to_ibuf_still(SeqRenderData context, Sequence * seq, float nr,
 			       ImBuf * ibuf)
 {
-	if (nr == 0) {
-		seq_stripelem_cache_put(
-			context, seq, seq->start, 
-			SEQ_STRIPELEM_IBUF_STARTSTILL, IMB_dupImBuf(ibuf));
-	} 
+	if (nr == 0 || nr == seq->len - 1) {
+		/* we have to store a copy, since the passed ibuf
+		   could be preprocessed afterwards (thereby silently
+		   changing the cached image... */
+		ibuf = IMB_dupImBuf(ibuf);
 
-	if (nr == seq->len - 1) {
-		seq_stripelem_cache_put(
-			context, seq, seq->start, 
-			SEQ_STRIPELEM_IBUF_ENDSTILL, IMB_dupImBuf(ibuf));
+		if (nr == 0) {
+			seq_stripelem_cache_put(
+				context, seq, seq->start, 
+				SEQ_STRIPELEM_IBUF_STARTSTILL, ibuf);
+		} 
+
+		if (nr == seq->len - 1) {
+			seq_stripelem_cache_put(
+				context, seq, seq->start, 
+				SEQ_STRIPELEM_IBUF_ENDSTILL, ibuf);
+		}
+
+		IMB_freeImBuf(ibuf);
 	}
 }