BatchRenderer: do not prune cached frames next to the current one

there is no any reason to drop frames that would be re-evaluated
just a few ticks later

Change-Id: Ieda6cf5784319fe6b35e82ee520ee4abddaab703
Reviewed-by: Rebecca Worledge <rebecca.worledge@theqtcompany.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/imports/rasterrenderer/batchrenderer.cpp b/src/imports/rasterrenderer/batchrenderer.cpp
index 2a6f373..84e5a2f 100644
--- a/src/imports/rasterrenderer/batchrenderer.cpp
+++ b/src/imports/rasterrenderer/batchrenderer.cpp
@@ -140,11 +140,13 @@ bool BatchRenderer::gotoFrame(LottieAnimation *animator, int frame)
 void BatchRenderer::pruneFrameCache(Entry* e)
 {
     QHash<int, BMBase*>::iterator it = e->frameCache.begin();
-
     while (it != e->frameCache.end()) {
-        if (it.key() == e->currentFrame) {
+        int frame = it.key();
+        if ((frame - e->currentFrame) * e->animDir >= 0) { // same frame or same direction
             ++it;
         } else {
+            qCDebug(lcLottieQtBodymovinRenderThread) << "Animator:" << static_cast<void*>(e->animator)
+                                                     << "Remove frame from cache" << frame;
             delete it.value();
             it = e->frameCache.erase(it);
         }