From 49e96d857a252c61ad3272d39b3ec842d598336f Mon Sep 17 00:00:00 2001
From: Ilya Fedin <fedin-ilja2010@ya.ru>
Date: Tue, 13 Oct 2020 00:37:55 +0400
Subject: [PATCH] Add drag distance for move-by-titlebar to process double
 click right

---
 .../SourceFiles/window/window_title_qt.cpp    | 38 +++++++++++++++----
 Telegram/SourceFiles/window/window_title_qt.h |  5 ++-
 2 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/Telegram/SourceFiles/window/window_title_qt.cpp b/Telegram/SourceFiles/window/window_title_qt.cpp
index 01aaca62b5..71cb2118a2 100644
--- a/Telegram/SourceFiles/window/window_title_qt.cpp
+++ b/Telegram/SourceFiles/window/window_title_qt.cpp
@@ -20,6 +20,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 
 #include <QtGui/QGuiApplication>
 #include <QtGui/QWindow>
+#include <QtWidgets/QApplication>
 
 namespace Window {
 namespace {
@@ -231,17 +232,26 @@ void TitleWidgetQt::resizeEvent(QResizeEvent *e) {
 
 void TitleWidgetQt::mousePressEvent(QMouseEvent *e) {
 	if (e->button() == Qt::LeftButton) {
-		startMove();
+		if ((crl::now() - _pressedForMoveTime)
+			< QApplication::doubleClickInterval()) {
+			if (_maximizedState) {
+				window()->setWindowState(Qt::WindowNoState);
+			} else {
+				window()->setWindowState(Qt::WindowMaximized);
+			}
+		} else {
+			_pressedForMove = true;
+			_pressedForMoveTime = crl::now();
+			_pressedForMovePoint = e->windowPos().toPoint();
+		}
 	} else if (e->button() == Qt::RightButton) {
 		Platform::ShowWindowMenu(window()->windowHandle());
 	}
 }
 
-void TitleWidgetQt::mouseDoubleClickEvent(QMouseEvent *e) {
-	if (_maximizedState) {
-		window()->setWindowState(Qt::WindowNoState);
-	} else {
-		window()->setWindowState(Qt::WindowMaximized);
+void TitleWidgetQt::mouseReleaseEvent(QMouseEvent *e) {
+	if (e->button() == Qt::LeftButton) {
+		_pressedForMove = false;
 	}
 }
 
@@ -250,14 +260,26 @@ bool TitleWidgetQt::eventFilter(QObject *obj, QEvent *e) {
 		|| e->type() == QEvent::MouseButtonPress) {
 		if (window()->isAncestorOf(static_cast<QWidget*>(obj))) {
 			const auto mouseEvent = static_cast<QMouseEvent*>(e);
-			const auto edges = edgesFromPos(
-				mouseEvent->windowPos().toPoint());
+			const auto currentPoint = mouseEvent->windowPos().toPoint();
+			const auto edges = edgesFromPos(currentPoint);
+			const auto dragDistance = QApplication::startDragDistance();
 
 			if (e->type() == QEvent::MouseMove
 				&& mouseEvent->buttons() == Qt::NoButton) {
+				if (_pressedForMove) {
+					_pressedForMove = false;
+				}
+
 				updateCursor(edges);
 			}
 
+			if (e->type() == QEvent::MouseMove
+				&& _pressedForMove
+				&& ((currentPoint - _pressedForMovePoint).manhattanLength()
+					>= dragDistance)) {
+				return startMove();
+			}
+
 			if (e->type() == QEvent::MouseButtonPress
 				&& mouseEvent->button() == Qt::LeftButton
 				&& !_maximizedState) {
diff --git a/Telegram/SourceFiles/window/window_title_qt.h b/Telegram/SourceFiles/window/window_title_qt.h
index 40f823b0b6..126711e954 100644
--- a/Telegram/SourceFiles/window/window_title_qt.h
+++ b/Telegram/SourceFiles/window/window_title_qt.h
@@ -39,7 +39,7 @@ protected:
 	void paintEvent(QPaintEvent *e) override;
 	void resizeEvent(QResizeEvent *e) override;
 	void mousePressEvent(QMouseEvent *e) override;
-	void mouseDoubleClickEvent(QMouseEvent *e) override;
+	void mouseReleaseEvent(QMouseEvent *e) override;
 
 	bool eventFilter(QObject *obj, QEvent *e) override;
 
@@ -73,6 +73,9 @@ private:
 	bool _windowWasFrameless = false;
 	bool _cursorOverriden = false;
 	bool _extentsSet = false;
+	bool _pressedForMove = false;
+	crl::time _pressedForMoveTime = 0;
+	QPoint _pressedForMovePoint;
 
 };