From 61dd75a2ed0cff39e0f007feb9736848aaf41504 Mon Sep 17 00:00:00 2001
From: itsmattkc <itsmattkc@gmail.com>
Date: Tue, 28 Apr 2020 23:55:40 +1000
Subject: [PATCH] scopes: only update if visible

Updating scopes can require heavy processing so we limit updates to only
when the scope is visible
---
 app/widget/scope/histogram/histogram.cpp | 11 ++++++++++-
 app/widget/scope/histogram/histogram.h   |  2 ++
 app/widget/scope/waveform/waveform.cpp   |  9 ++++++++-
 app/widget/scope/waveform/waveform.h     |  2 ++
 4 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/app/widget/scope/histogram/histogram.cpp b/app/widget/scope/histogram/histogram.cpp
index ab7cb66e1..b9028f85a 100644
--- a/app/widget/scope/histogram/histogram.cpp
+++ b/app/widget/scope/histogram/histogram.cpp
@@ -49,7 +49,9 @@ void HistogramScope::SetBuffer(Frame* frame)
 {
   buffer_ = frame;
 
-  StartUpdate();
+  if (isVisible()) {
+    StartUpdate();
+  }
 }
 
 void HistogramScope::FinishedProcessing(QVector<double> red, QVector<double> green, QVector<double> blue)
@@ -111,6 +113,13 @@ void HistogramScope::StartUpdate()
   }
 }
 
+void HistogramScope::showEvent(QShowEvent* e)
+{
+  ManagedDisplayWidget::showEvent(e);
+
+  StartUpdate();
+}
+
 HistogramScopeWorker::HistogramScopeWorker() :
   cancelled_(false)
 {
diff --git a/app/widget/scope/histogram/histogram.h b/app/widget/scope/histogram/histogram.h
index ea5175726..3efad3919 100644
--- a/app/widget/scope/histogram/histogram.h
+++ b/app/widget/scope/histogram/histogram.h
@@ -78,6 +78,8 @@ protected:
 
   virtual void ColorProcessorChangedEvent() override;
 
+  virtual void showEvent(QShowEvent* e) override;
+
 private:
   void StartUpdate();
 
diff --git a/app/widget/scope/waveform/waveform.cpp b/app/widget/scope/waveform/waveform.cpp
index d8f6b6e71..21ef63dc3 100644
--- a/app/widget/scope/waveform/waveform.cpp
+++ b/app/widget/scope/waveform/waveform.cpp
@@ -49,6 +49,13 @@ void WaveformScope::SetBuffer(Frame *frame)
   UploadTextureFromBuffer();
 }
 
+void WaveformScope::showEvent(QShowEvent* e)
+{
+  ManagedDisplayWidget::showEvent(e);
+
+  UploadTextureFromBuffer();
+}
+
 void WaveformScope::initializeGL()
 {
   ManagedDisplayWidget::initializeGL();
@@ -93,7 +100,7 @@ void WaveformScope::paintGL()
 
 void WaveformScope::UploadTextureFromBuffer()
 {
-  if (!buffer_) {
+  if (!buffer_ || !isVisible()) {
     return;
   }
 
diff --git a/app/widget/scope/waveform/waveform.h b/app/widget/scope/waveform/waveform.h
index dd9d40452..6d2e808f5 100644
--- a/app/widget/scope/waveform/waveform.h
+++ b/app/widget/scope/waveform/waveform.h
@@ -45,6 +45,8 @@ protected:
 
   virtual void paintGL() override;
 
+  virtual void showEvent(QShowEvent* e) override;
+
 private:
   void UploadTextureFromBuffer();