commit 69c32ef7e51a46442ab68ccba9eee8a4e37a241a
author Wan-Teh Chang <wtc@google.com> Fri Dec 18 12:16:42 2020 -0800
committer Joe Drago <joedrago@gmail.com> Fri Dec 18 12:59:51 2020 -0800
tree 308c099e4540e7981fe034e7c77d6c31600cda89
parent 00cbb7788aa083356e705770dfc94ef44f19c278

Fix two bugs in alpha in grid image encoding

Set the gridCols and gridRows fields of gridAlphaItem.

Pass cellIndex, not 0, as the last argument to the
avifEncoderDataCreateItem(encoder->data, "av01", "Alpha", 6, 0) call.

src/write.c

diff --git a/src/write.c b/src/write.c
index f45afcd..7082851 100644
--- a/src/write.c
+++ b/src/write.c
@@ -512,11 +512,13 @@
                 gridAlphaItem->alpha = AVIF_TRUE;
                 gridAlphaItem->irefToID = encoder->data->primaryItemID;
                 gridAlphaItem->irefType = "auxl";
+                gridAlphaItem->gridCols = gridCols;
+                gridAlphaItem->gridRows = gridRows;
                 gridAlphaID = gridAlphaItem->id;
             }
 
             for (uint32_t cellIndex = 0; cellIndex < cellCount; ++cellIndex) {
-                avifEncoderItem * item = avifEncoderDataCreateItem(encoder->data, "av01", "Alpha", 6, 0);
+                avifEncoderItem * item = avifEncoderDataCreateItem(encoder->data, "av01", "Alpha", 6, cellIndex);
                 item->codec = avifCodecCreate(encoder->codecChoice, AVIF_CODEC_FLAG_CAN_ENCODE);
                 if (!item->codec) {
                     return AVIF_RESULT_NO_CODEC_AVAILABLE;