From ec023ac66004fdfbda9a4de7a414157626e0e6b6 Mon Sep 17 00:00:00 2001
From: baldurk <baldurk@baldurk.org>
Date: Wed, 2 Sep 2020 15:37:58 +0100
Subject: [PATCH] Avoid unnecessary re-layouts when populating thumbnails

---
 qrenderdoc/Widgets/ResourcePreview.h  |  6 ++----
 qrenderdoc/Widgets/ThumbnailStrip.cpp | 22 ++++++++++++++++------
 qrenderdoc/Windows/TextureViewer.cpp  |  3 +++
 3 files changed, 21 insertions(+), 10 deletions(-)

diff --git a/qrenderdoc/Widgets/ResourcePreview.h b/qrenderdoc/Widgets/ResourcePreview.h
index 927689cce..c11a0dcb1 100644
--- a/qrenderdoc/Widgets/ResourcePreview.h
+++ b/qrenderdoc/Widgets/ResourcePreview.h
@@ -58,10 +58,8 @@ public:
   void setActive(bool b)
   {
     m_Active = b;
-    if(b)
-      show();
-    else
-      hide();
+    // we unconditionally hide the preview, the thumbnail strip will show it
+    hide();
   }
   bool isActive() { return m_Active; }
   void setSize(QSize s);
diff --git a/qrenderdoc/Widgets/ThumbnailStrip.cpp b/qrenderdoc/Widgets/ThumbnailStrip.cpp
index 7214bfa89..e2fe7fd31 100644
--- a/qrenderdoc/Widgets/ThumbnailStrip.cpp
+++ b/qrenderdoc/Widgets/ThumbnailStrip.cpp
@@ -77,6 +77,9 @@ void ThumbnailStrip::showEvent(QShowEvent *event)
 
 void ThumbnailStrip::refreshLayout()
 {
+  if(updatesEnabled())
+    setUpdatesEnabled(false);
+
   QRect avail = geometry();
   avail.adjust(6, 6, -6, -6);
 
@@ -97,9 +100,7 @@ void ThumbnailStrip::refreshLayout()
     ui->scrollArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
 
     delete layout;
-    layout = new QHBoxLayout(ui->scrollAreaWidgetContents);
-    for(ResourcePreview *w : m_Thumbnails)
-      layout->addWidget(w);
+    layout = new QHBoxLayout();
     layout->setSpacing(6);
     layout->setContentsMargins(6, 6, 6, 6);
     layout->setAlignment(Qt::AlignTop);
@@ -139,9 +140,7 @@ void ThumbnailStrip::refreshLayout()
     ui->scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
 
     delete layout;
-    layout = new QVBoxLayout(ui->scrollAreaWidgetContents);
-    for(ResourcePreview *w : m_Thumbnails)
-      layout->addWidget(w);
+    layout = new QVBoxLayout();
     layout->setSpacing(6);
     layout->setContentsMargins(6, 6, 6, 6);
     layout->setAlignment(Qt::AlignTop);
@@ -172,4 +171,15 @@ void ThumbnailStrip::refreshLayout()
         c->setSize(QSize(avail.width(), aspectHeight));
     }
   }
+
+  for(ResourcePreview *w : m_Thumbnails)
+    layout->addWidget(w);
+
+  for(ResourcePreview *w : m_Thumbnails)
+    if(w->isActive())
+      w->show();
+
+  ui->scrollAreaWidgetContents->setLayout(layout);
+
+  setUpdatesEnabled(true);
 }
diff --git a/qrenderdoc/Windows/TextureViewer.cpp b/qrenderdoc/Windows/TextureViewer.cpp
index 60bf96448..9a37cbba6 100644
--- a/qrenderdoc/Windows/TextureViewer.cpp
+++ b/qrenderdoc/Windows/TextureViewer.cpp
@@ -3013,6 +3013,9 @@ void TextureViewer::OnEventChanged(uint32_t eventId)
   int outIndex = 0;
   int inIndex = 0;
 
+  ui->outputThumbs->setUpdatesEnabled(false);
+  ui->inputThumbs->setUpdatesEnabled(false);
+
   bool copy = false, clear = false, compute = false;
   Following::GetDrawContext(m_Ctx, copy, clear, compute);