From cb72736f528f23d3a7ba1770a4524a43e7c781eb Mon Sep 17 00:00:00 2001
From: itsmattkc <itsmattkc@gmail.com>
Date: Thu, 21 May 2020 03:09:39 +1000
Subject: [PATCH] viewer: keep track of request order and ignore old requests

Prevents visual confusion with frames that were requested before the most recent
but arrived after.
---
 app/widget/viewer/viewer.cpp | 15 +++++++++++++--
 app/widget/viewer/viewer.h   |  2 ++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/app/widget/viewer/viewer.cpp b/app/widget/viewer/viewer.cpp
index 1371aaf64..66ec98831 100644
--- a/app/widget/viewer/viewer.cpp
+++ b/app/widget/viewer/viewer.cpp
@@ -421,6 +421,8 @@ void ViewerWidget::UpdateTextureFromNode(const rational& time)
           this,
           &ViewerWidget::RendererGeneratedFrame);
 
+  nonqueue_watchers_.append(watcher);
+
   watcher->setFuture(GetFrame(time, true, true));
 }
 
@@ -695,9 +697,18 @@ void ViewerWidget::RendererGeneratedFrame()
 {
   QFutureWatcher<FramePtr>* watcher = static_cast<QFutureWatcher<FramePtr>*>(sender());
   FramePtr frame = watcher->result();
-  watcher->deleteLater();
 
-  SetDisplayImage(frame, false);
+  if (nonqueue_watchers_.contains(watcher)) {
+    while (!nonqueue_watchers_.isEmpty()) {
+      if (nonqueue_watchers_.takeFirst() == watcher) {
+        break;
+      }
+    }
+
+    SetDisplayImage(frame, false);
+  }
+
+  watcher->deleteLater();
 }
 
 void ViewerWidget::RendererGeneratedFrameForQueue()
diff --git a/app/widget/viewer/viewer.h b/app/widget/viewer/viewer.h
index 41f4a9d66..d7b65109d 100644
--- a/app/widget/viewer/viewer.h
+++ b/app/widget/viewer/viewer.h
@@ -231,6 +231,8 @@ private:
 
   bool prequeuing_;
 
+  QList< QFutureWatcher<FramePtr>* > nonqueue_watchers_;
+
 private slots:
   void PlaybackTimerUpdate();