From 0f306550bf19e09c9d74f5139e58555055032f09 Mon Sep 17 00:00:00 2001
From: itsmattkc <itsmattkc@gmail.com>
Date: Thu, 7 May 2020 03:04:40 +1000
Subject: [PATCH] slider: use custom dragging code on mac

The slider dragging implementation used for other platforms caused issues on
macOS. We now have a custom Mac implementation that doesn't cause problems, and
is arguably better than the other implementation anyway.
---
 app/CMakeLists.txt                |  6 ++++
 app/widget/slider/sliderlabel.cpp | 50 ++++++++++++++++++++-----------
 app/widget/slider/sliderlabel.h   |  2 ++
 3 files changed, 41 insertions(+), 17 deletions(-)

diff --git a/app/CMakeLists.txt b/app/CMakeLists.txt
index b22b69ced..2bcbd2de3 100644
--- a/app/CMakeLists.txt
+++ b/app/CMakeLists.txt
@@ -155,6 +155,12 @@ if (WIN32)
     PRIVATE
     DbgHelp
   )
+elseif (APPLE)
+  target_link_libraries(
+    ${OLIVE_TARGET}
+    PRIVATE
+    "-framework ApplicationServices"
+  )
 endif()
 
 set(OLIVE_TS_FILES
diff --git a/app/widget/slider/sliderlabel.cpp b/app/widget/slider/sliderlabel.cpp
index a54a54cf0..aee4a8409 100644
--- a/app/widget/slider/sliderlabel.cpp
+++ b/app/widget/slider/sliderlabel.cpp
@@ -22,6 +22,11 @@
 
 #include <QApplication>
 #include <QMouseEvent>
+#include <QDebug>
+
+#ifdef Q_OS_MAC
+#include <ApplicationServices/ApplicationServices.h>
+#endif
 
 OLIVE_NAMESPACE_ENTER
 
@@ -48,40 +53,51 @@ SliderLabel::SliderLabel(QWidget *parent) :
   setFocusPolicy(Qt::TabFocus);
 }
 
-void SliderLabel::mousePressEvent(QMouseEvent *ev)
+void SliderLabel::mousePressEvent(QMouseEvent *)
 {
-  QLabel::mousePressEvent(ev);
+  emit drag_start();
 
+#if defined(Q_OS_MAC)
+  CGAssociateMouseAndMouseCursorPosition(false);
+  CGDisplayHideCursor(kCGDirectMainDisplay);
+  CGGetLastMouseDelta(nullptr, nullptr);
+#else
   drag_start_ = QCursor::pos();
 
   static_cast<QGuiApplication*>(QApplication::instance())->setOverrideCursor(Qt::BlankCursor);
-
-  emit drag_start();
+#endif
 }
 
-void SliderLabel::mouseMoveEvent(QMouseEvent *ev)
+void SliderLabel::mouseMoveEvent(QMouseEvent *)
 {
-  QLabel::mouseMoveEvent(ev);
-
-  QPoint current_pos = QCursor::pos();
-
-  int x_mvmt = current_pos.x() - drag_start_.x();
-  int y_mvmt = drag_start_.y() - current_pos.y();
-
-  emit dragged(x_mvmt + y_mvmt);
+  int32_t x_mvmt, y_mvmt;
 
   // Keep cursor in the same position
+#if defined(Q_OS_MAC)
+  CGGetLastMouseDelta(&x_mvmt, &y_mvmt);
+#else
+  QPoint current_pos = QCursor::pos();
+
+  x_mvmt = current_pos.x() - drag_start_.x();
+  y_mvmt = drag_start_.y() - current_pos.y();
+
   QCursor::setPos(drag_start_);
+#endif
+
+  emit dragged(x_mvmt + y_mvmt);
 }
 
-void SliderLabel::mouseReleaseEvent(QMouseEvent *ev)
+void SliderLabel::mouseReleaseEvent(QMouseEvent *)
 {
-  QWidget::mouseReleaseEvent(ev);
+#if defined(Q_OS_MAC)
+  CGAssociateMouseAndMouseCursorPosition(true);
+  CGDisplayShowCursor(kCGDirectMainDisplay);
+#else
+  static_cast<QGuiApplication*>(QApplication::instance())->restoreOverrideCursor();
+#endif
 
   // Emit a clicked signal
   emit drag_stop();
-
-  static_cast<QGuiApplication*>(QApplication::instance())->restoreOverrideCursor();
 }
 
 void SliderLabel::focusInEvent(QFocusEvent *event)
diff --git a/app/widget/slider/sliderlabel.h b/app/widget/slider/sliderlabel.h
index 92771e669..c83e86bfc 100644
--- a/app/widget/slider/sliderlabel.h
+++ b/app/widget/slider/sliderlabel.h
@@ -54,6 +54,8 @@ signals:
 private:
   QPoint drag_start_;
 
+  bool cancel_mm_event_;
+
 };
 
 OLIVE_NAMESPACE_EXIT