From ccaedc3987e1c7d664584ad3220c601373f63fd2 Mon Sep 17 00:00:00 2001
From: kornes <28986062+kornes@users.noreply.github.com>
Date: Fri, 13 Oct 2023 17:19:52 +0000
Subject: [PATCH] perf: reduce repaints amount caused by selection (#4889)

Co-authored-by: nerix <nero.9@hotmail.de>
Co-authored-by: Rasmus Karlsson <rasmus.karlsson@pajlada.com>
---
 CHANGELOG.md                       |  1 +
 src/messages/Selection.hpp         | 12 +++++++-
 src/widgets/helper/ChannelView.cpp | 46 +++++++++---------------------
 src/widgets/helper/ChannelView.hpp |  1 -
 4 files changed, 26 insertions(+), 34 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 99074077f..af1f47a88 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -39,6 +39,7 @@
 - Dev: Add a compile-time flag `USE_SYSTEM_MINIAUDIO` which can be turned on to use the system miniaudio. (#4867)
 - Dev: Update vcpkg to use Qt6. (#4872)
 - Dev: Replace `boost::optional` with `std::optional`. (#4877)
+- Dev: Improve performance by reducing repaints caused by selections. (#4889)
 
 ## 2.4.6
 
diff --git a/src/messages/Selection.hpp b/src/messages/Selection.hpp
index 6563ff9e2..5af3612bc 100644
--- a/src/messages/Selection.hpp
+++ b/src/messages/Selection.hpp
@@ -38,7 +38,7 @@ struct SelectionItem {
 
     bool operator!=(const SelectionItem &b) const
     {
-        return this->operator==(b);
+        return !this->operator==(b);
     }
 };
 
@@ -62,6 +62,16 @@ struct Selection {
         }
     }
 
+    bool operator==(const Selection &b) const
+    {
+        return this->start == b.start && this->end == b.end;
+    }
+
+    bool operator!=(const Selection &b) const
+    {
+        return !this->operator==(b);
+    }
+
     bool isEmpty() const
     {
         return this->start == this->end;
diff --git a/src/widgets/helper/ChannelView.cpp b/src/widgets/helper/ChannelView.cpp
index 31272e601..de185eb62 100644
--- a/src/widgets/helper/ChannelView.cpp
+++ b/src/widgets/helper/ChannelView.cpp
@@ -1091,18 +1091,13 @@ void ChannelView::resizeEvent(QResizeEvent *)
 void ChannelView::setSelection(const SelectionItem &start,
                                const SelectionItem &end)
 {
-    // selections
-    if (!this->selecting_ && start != end)
+    auto newSelection = Selection(start, end);
+    if (this->selection_ != newSelection)
     {
-        // this->messagesAddedSinceSelectionPause_ = 0;
-
-        this->selecting_ = true;
-        // this->pausedBySelection_ = true;
+        this->selection_ = newSelection;
+        this->selectionChanged.invoke();
+        this->update();
     }
-
-    this->selection_ = Selection(start, end);
-
-    this->selectionChanged.invoke();
 }
 
 MessageElementFlags ChannelView::getFlags() const
@@ -1520,13 +1515,10 @@ void ChannelView::mouseMoveEvent(QMouseEvent *event)
     // is selecting
     if (this->isLeftMouseDown_)
     {
-        // this->pause(PauseReason::Selecting, 300);
         auto index = layout->getSelectionIndex(relativePos);
 
         this->setSelection(this->selection_.start,
                            SelectionItem(messageIndex, index));
-
-        this->queueUpdate();
     }
 
     // message under cursor is collapsed
@@ -1980,6 +1972,15 @@ void ChannelView::mouseReleaseEvent(QMouseEvent *event)
             {
                 return;
             }
+
+            // Triple-clicking a message selects the whole message
+            if (foundElement && this->clickTimer_->isActive() &&
+                (fabsf(distanceBetweenPoints(this->lastDClickPosition_,
+                                             event->screenPos())) < 10.f))
+            {
+                this->selectWholeMessage(layout.get(), messageIndex);
+                return;
+            }
         }
         else
         {
@@ -2061,15 +2062,6 @@ void ChannelView::mouseReleaseEvent(QMouseEvent *event)
 
     const MessageLayoutElement *hoverLayoutElement =
         layout->getElementAt(relativePos);
-    // Triple-clicking a message selects the whole message
-    if (this->clickTimer_->isActive() && this->selecting_)
-    {
-        if (fabsf(distanceBetweenPoints(this->lastDClickPosition_,
-                                        event->screenPos())) < 10.f)
-        {
-            this->selectWholeMessage(layout.get(), messageIndex);
-        }
-    }
 
     // handle the click
     this->handleMouseClick(event, hoverLayoutElement, layout);
@@ -2084,16 +2076,6 @@ void ChannelView::handleMouseClick(QMouseEvent *event,
     switch (event->button())
     {
         case Qt::LeftButton: {
-            if (this->selecting_)
-            {
-                // this->pausedBySelection = false;
-                this->selecting_ = false;
-                // this->pauseTimeout.stop();
-                // this->pausedTemporarily = false;
-
-                this->queueLayout();
-            }
-
             if (hoveredElement == nullptr)
             {
                 return;
diff --git a/src/widgets/helper/ChannelView.hpp b/src/widgets/helper/ChannelView.hpp
index a728920cb..27ae83cfe 100644
--- a/src/widgets/helper/ChannelView.hpp
+++ b/src/widgets/helper/ChannelView.hpp
@@ -330,7 +330,6 @@ private:
     } cursors_;
 
     Selection selection_;
-    bool selecting_ = false;
 
     const Context context_;