Throttle flex layout calculation calls to improve performance (#268)

* Throttling multiple calls to setGeometry

* Lint

CMakeLists.txt

@@ -83,6 +83,7 @@ add_library(${CORE_WIDGETS_ADDON} SHARED
     "${PROJECT_SOURCE_DIR}/src/cpp/lib/core/FlexLayout/flexlayout_wrap.cpp"
     # Custom widgets (include them for automoc since they contain Q_OBJECT)
     "${PROJECT_SOURCE_DIR}/src/cpp/include/nodegui/QtCore/QObject/nobject.hpp"
+    "${PROJECT_SOURCE_DIR}/src/cpp/include/nodegui/core/FlexLayout/flexlayout.hpp"
     "${PROJECT_SOURCE_DIR}/src/cpp/include/nodegui/QtGui/QMovie/nmovie.hpp"
     "${PROJECT_SOURCE_DIR}/src/cpp/include/nodegui/QtWidgets/QWidget/nwidget.hpp"
     "${PROJECT_SOURCE_DIR}/src/cpp/include/nodegui/QtWidgets/QLabel/nlabel.hpp"

src/cpp/include/nodegui/Extras/Utils/nutils.h

@@ -5,7 +5,7 @@
 #include <QPointer>
 #include <QVariant>
 
-#include "core/FlexLayout/flexlayout.h"
+#include "core/FlexLayout/flexlayout.hpp"
 #include "core/FlexLayout/flexutils.h"
 namespace extrautils {
 

src/cpp/include/nodegui/core/FlexLayout/flexlayout.hpp

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <QLayout>
+#include <QTimer>
 
 #include "core/Events/eventwidget_macro.h"
 #include "deps/yoga/YGNode.h"
@@ -19,6 +20,7 @@ YGNodeNew(); FlexLayout * flayout = new FlexLayout(container,root);
  */
 
 class FlexLayout : public QLayout, public EventWidget {
+  Q_OBJECT
  private:
   YGNodeRef node;
   YGNodeRef getRootNode(YGNodeRef node) const;
@@ -26,6 +28,13 @@ class FlexLayout : public QLayout, public EventWidget {
   void restoreNodeMinStyle(YGValue &previousMinWidth,
                            YGValue &previousMinHeight);
 
+  // performance memebers
+  QTimer throttleTimer;
+  QRect cachedRect;
+  // end of performance memeber
+ private slots:
+  void performLayout();
+
  public:
   FlexLayout(QWidget *parentWidget = nullptr, YGNodeRef parentNode = nullptr);
   ~FlexLayout() override;
@@ -45,3 +54,5 @@ class FlexLayout : public QLayout, public EventWidget {
 
   EVENTWIDGET_IMPLEMENTATIONS(QLayout)
 };
+
+// class FlexLayoutWorker: public Q

src/cpp/include/nodegui/core/FlexLayout/flexlayout_wrap.h

@@ -6,7 +6,7 @@
 #include <QPointer>
 
 #include "QtWidgets/QLayout/qlayout_macro.h"
-#include "flexlayout.h"
+#include "flexlayout.hpp"
 
 class FlexLayoutWrap : public Napi::ObjectWrap<FlexLayoutWrap> {
  private:

src/cpp/lib/core/FlexLayout/flexlayout.cpp

@@ -1,8 +1,9 @@
-#include "core/FlexLayout/flexlayout.h"
+#include "core/FlexLayout/flexlayout.hpp"
 
 #include <QDebug>
 #include <QWidget>
 
+#include "Extras/Utils/nutils.h"
 #include "core/FlexLayout/flexitem.h"
 #include "core/FlexLayout/flexutils.h"
 #include "core/YogaWidget/yogawidget.h"
@@ -10,6 +11,12 @@
 FlexLayout::FlexLayout(QWidget* parentWidget, YGNodeRef parentNode)
     : QLayout(parentWidget) {
   this->node = parentNode;
+  // Throttle the setGeometry calls that may happen when dealing with huge
+  // lists.
+  this->throttleTimer.setTimerType(Qt::PreciseTimer);
+  this->throttleTimer.setSingleShot(true);
+  QObject::connect(&this->throttleTimer, &QTimer::timeout, this,
+                   &FlexLayout::performLayout);
 }
 
 FlexLayout::~FlexLayout() {
@@ -147,9 +154,19 @@ QSize FlexLayout::minimumSize() const {
 }
 
 void FlexLayout::setGeometry(const QRect& rect) {
+  this->cachedRect = rect;
+  if (this->throttleTimer.isActive()) {
+    return;
+  }
+  this->throttleTimer.start(10);
+  // This will call performLayout and throttle requests between 10ms.
+}
+
+void FlexLayout::performLayout() {
   if (!this->node) {
     return;
   }
+  QRect rect = this->cachedRect;
   if (!rect.isValid() || rect != geometry()) {
     bool isSizeControlled = flexutils::isFlexNodeSizeControlled(this->node);
     YGValue prevStyleMinWidth = YGNodeStyleGetMinWidth(this->node);