commit ae834f57818c138a79e3f35ad106a491f80237b5
author Leon Scroggins III <scroggo@google.com> Tue Dec 10 14:24:18 2019 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Tue Dec 10 21:41:10 2019 +0000
tree e528dde6e3dc28ef88884134a4c05082233c8ad7
parent aebc5f8bd7340e1ec7683ec82fafa7281025ca4a

SkWebpCodec: enable a loop count of 1

Commit 557fbb added animation support to SkWebpCodec, with the intent to
match Chromium. This was during the ~1.5 year period between
crbug.com/592735 and crbug.com/649264 when Chromium attempted to align
WebP with GIF, and play the animation once more than the stored number
(see crbug.com/592735). This was later reverted, because it means that a
WebP is unable to play an animation a single time (see
crbug.com/649264). This commit catches SkWebpCodec up with Chromium.

Add a legacy build flag (SK_LEGACY_WEBP_LOOP_COUNT) so we can stage the
change on Android.

Change-Id: If07e00d5e070847ceeb9ce27cd78a846974cdb4d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/259161
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

src/codec/SkWebpCodec.cpp

diff --git a/src/codec/SkWebpCodec.cpp b/src/codec/SkWebpCodec.cpp
index a90d452..9e2dead 100644
--- a/src/codec/SkWebpCodec.cpp
+++ b/src/codec/SkWebpCodec.cpp
@@ -220,12 +220,15 @@
         return 0;
     }
 
-    const int repCount = WebPDemuxGetI(fDemux.get(), WEBP_FF_LOOP_COUNT);
-    if (0 == repCount) {
+    int loopCount = WebPDemuxGetI(fDemux.get(), WEBP_FF_LOOP_COUNT);
+    if (0 == loopCount) {
         return kRepetitionCountInfinite;
     }
 
-    return repCount;
+#ifndef SK_LEGACY_WEBP_LOOP_COUNT
+    loopCount--;
+#endif
+    return loopCount;
 }
 
 int SkWebpCodec::onGetFrameCount() {

tests/CodecAnimTest.cpp

diff --git a/tests/CodecAnimTest.cpp b/tests/CodecAnimTest.cpp
index 6e895f7..44446bc 100644
--- a/tests/CodecAnimTest.cpp
+++ b/tests/CodecAnimTest.cpp
@@ -155,13 +155,22 @@
         { "images/blendBG.webp", 7,
             { 0, kNoFrame, kNoFrame, kNoFrame, 4, 4 },
             { kOpaque, kOpaque, kUnpremul, kOpaque, kUnpremul, kUnpremul },
-            { 525, 500, 525, 437, 609, 729, 444 }, 7,
+            { 525, 500, 525, 437, 609, 729, 444 },
+#ifdef SK_LEGACY_WEBP_LOOP_COUNT
+            7,
+#else
+            6,
+#endif
             { kKeep, kKeep, kKeep, kKeep, kKeep, kKeep, kKeep } },
         { "images/required.webp", 7,
             { 0, 1, 1, kNoFrame, 4, 4 },
             { kOpaque, kUnpremul, kUnpremul, kOpaque, kOpaque, kOpaque },
             { 100, 100, 100, 100, 100, 100, 100 },
+#ifdef SK_LEGACY_WEBP_LOOP_COUNT
             1,
+#else
+            0,
+#endif
             { kKeep, kRestoreBG, kKeep, kKeep, kKeep, kRestoreBG, kKeep } },
     };