Improve window extension by third column.

Telegram/SourceFiles/auth_session.cpp

@@ -78,6 +78,7 @@ QByteArray AuthSessionData::serialize() const {
 			0,
 			1000000));
 		stream << qint32(_variables.thirdColumnWidth.current());
+		stream << qint32(_variables.thirdSectionExtendedBy);
 	}
 	return result;
 }
@@ -101,6 +102,7 @@ void AuthSessionData::constructFromSerialized(const QByteArray &serialized) {
 	qint32 smallDialogsList = 0;
 	float64 dialogsWidthRatio = _variables.dialogsWidthRatio.current();
 	int thirdColumnWidth = _variables.thirdColumnWidth.current();
+	int thirdSectionExtendedBy = _variables.thirdSectionExtendedBy;
 	stream >> selectorTab;
 	stream >> lastSeenWarningSeen;
 	if (!stream.atEnd()) {
@@ -145,6 +147,9 @@ void AuthSessionData::constructFromSerialized(const QByteArray &serialized) {
 
 		stream >> value;
 		thirdColumnWidth = value;
+
+		stream >> value;
+		thirdSectionExtendedBy = value;
 	}
 	if (stream.status() != QDataStream::Ok) {
 		LOG(("App Error: Bad data for AuthSessionData::constructFromSerialized()"));
@@ -179,6 +184,7 @@ void AuthSessionData::constructFromSerialized(const QByteArray &serialized) {
 	_variables.smallDialogsList = smallDialogsList;
 	_variables.dialogsWidthRatio = dialogsWidthRatio;
 	_variables.thirdColumnWidth = thirdColumnWidth;
+	_variables.thirdSectionExtendedBy = thirdSectionExtendedBy;
 	if (_variables.thirdSectionInfoEnabled) {
 		_variables.tabbedSelectorSectionEnabled = false;
 	}

Telegram/SourceFiles/auth_session.h

@@ -170,6 +170,12 @@ public:
 		return _thirdSectionInfoEnabledValue.events_starting_with(
 			thirdSectionInfoEnabled());
 	}
+	int thirdSectionExtendedBy() const {
+		return _variables.thirdSectionExtendedBy;
+	}
+	void setThirdSectionExtendedBy(int savedValue) {
+		_variables.thirdSectionExtendedBy = savedValue;
+	}
 	bool tabbedReplacedWithInfo() const {
 		return _tabbedReplacedWithInfo;
 	}
@@ -342,6 +348,7 @@ private:
 		base::flat_set<PeerId> groupStickersSectionHidden;
 		bool thirdSectionInfoEnabled = true; // per-window
 		bool smallDialogsList = false; // per-window
+		int thirdSectionExtendedBy = -1; // per-window
 		rpl::variable<float64> dialogsWidthRatio
 			= kDefaultDialogsWidthRatio; // per-window
 		rpl::variable<int> thirdColumnWidth

Telegram/SourceFiles/window/main_window.cpp

@@ -369,20 +369,35 @@ void MainWindow::showRightColumn(object_ptr<TWidget> widget) {
 	}
 }
 
-bool MainWindow::canExtendWidthBy(int addToWidth) {
+int MainWindow::maximalExtendBy() const {
 	auto desktop = QDesktopWidget().availableGeometry(this);
-	return (width() + addToWidth) <= desktop.width();
+	return std::max(desktop.width() - geometry().width(), 0);
 }
 
-void MainWindow::tryToExtendWidthBy(int addToWidth) {
+bool MainWindow::canExtendNoMove(int extendBy) const {
 	auto desktop = QDesktopWidget().availableGeometry(this);
-	auto newWidth = qMin(width() + addToWidth, desktop.width());
-	auto newLeft = qMin(x(), desktop.x() + desktop.width() - newWidth);
-	if (x() != newLeft || width() != newWidth) {
-		setGeometry(newLeft, y(), newWidth, height());
+	auto inner = geometry();
+	auto innerRight = (inner.x() + inner.width() + extendBy);
+	auto desktopRight = (desktop.x() + desktop.width());
+	return innerRight <= desktopRight;
+}
+
+int MainWindow::tryToExtendWidthBy(int addToWidth) {
+	auto desktop = QDesktopWidget().availableGeometry(this);
+	auto inner = geometry();
+	accumulate_min(
+		addToWidth,
+		std::max(desktop.width() - inner.width(), 0));
+	auto newWidth = inner.width() + addToWidth;
+	auto newLeft = std::min(
+		inner.x(),
+		desktop.x() + desktop.width() - newWidth);
+	if (inner.x() != newLeft || inner.width() != newWidth) {
+		setGeometry(newLeft, inner.y(), newWidth, inner.height());
 	} else {
 		updateControlsGeometry();
 	}
+	return addToWidth;
 }
 
 void MainWindow::launchDrag(std::unique_ptr<QMimeData> data) {

Telegram/SourceFiles/window/main_window.h

@@ -76,8 +76,11 @@ public:
 	}
 
 	void showRightColumn(object_ptr<TWidget> widget);
-	bool canExtendWidthBy(int addToWidth);
-	void tryToExtendWidthBy(int addToWidth);
+	int maximalExtendBy() const;
+	bool canExtendNoMove(int extendBy) const;
+
+	// Returns how much could the window get extended.
+	int tryToExtendWidthBy(int addToWidth);
 
 	virtual void updateTrayMenu(bool force = false) {
 	}

Telegram/SourceFiles/window/window_controller.cpp

@@ -167,12 +167,9 @@ Controller::ShrinkResult Controller::shrinkDialogsAndThirdColumns(
 
 bool Controller::canShowThirdSection() const {
 	auto currentLayout = computeColumnLayout();
-	auto extendBy = minimalThreeColumnWidth()
+	auto minimalExtendBy = minimalThreeColumnWidth()
 		- currentLayout.bodyWidth;
-	if (extendBy <= 0) {
-		return true;
-	}
-	return window()->canExtendWidthBy(extendBy);
+	return (minimalExtendBy <= window()->maximalExtendBy());
 }
 
 bool Controller::canShowThirdSectionWithoutResize() const {
@@ -197,14 +194,35 @@ void Controller::resizeForThirdSection() {
 	Auth().data().setTabbedSelectorSectionEnabled(false);
 	Auth().data().setThirdSectionInfoEnabled(false);
 
-	auto extendBy = qMax(
-		minimalThreeColumnWidth() - layout.bodyWidth,
-		countThirdColumnWidthFromRatio(layout.bodyWidth));
-	auto newBodyWidth = layout.bodyWidth + extendBy;
-	auto currentRatio = Auth().data().dialogsWidthRatio();
-	Auth().data().setDialogsWidthRatio(
-		(currentRatio * layout.bodyWidth) / newBodyWidth);
-	window()->tryToExtendWidthBy(extendBy);
+	auto wanted = countThirdColumnWidthFromRatio(layout.bodyWidth);
+	auto minimal = st::columnMinimalWidthThird;
+	auto extendBy = wanted;
+	auto extendedBy = [&] {
+		// Best - extend by third column without moving the window.
+		// Next - extend by minimal third column without moving.
+		// Next - show third column inside the window without moving.
+		// Last - extend with moving.
+		if (window()->canExtendNoMove(wanted)) {
+			return window()->tryToExtendWidthBy(wanted);
+		} else if (window()->canExtendNoMove(minimal)) {
+			extendBy = minimal;
+			return window()->tryToExtendWidthBy(minimal);
+		} else if (layout.bodyWidth >= minimalThreeColumnWidth()) {
+			return 0;
+		}
+		return window()->tryToExtendWidthBy(minimal);
+	}();
+	if (extendedBy) {
+		if (extendBy != Auth().data().thirdColumnWidth()) {
+			Auth().data().setThirdColumnWidth(extendBy);
+		}
+		auto newBodyWidth = layout.bodyWidth + extendedBy;
+		auto currentRatio = Auth().data().dialogsWidthRatio();
+		Auth().data().setDialogsWidthRatio(
+			(currentRatio * layout.bodyWidth) / newBodyWidth);
+	}
+	auto savedValue = (extendedBy == extendBy) ? -1 : extendedBy;
+	Auth().data().setThirdSectionExtendedBy(savedValue);
 
 	Auth().data().setTabbedSelectorSectionEnabled(
 		tabbedSelectorSectionEnabled);
@@ -218,11 +236,16 @@ void Controller::closeThirdSection() {
 	if (layout.windowLayout == Adaptive::WindowLayout::ThreeColumn) {
 		auto noResize = window()->isFullScreen()
 			|| window()->isMaximized();
+		auto savedValue = Auth().data().thirdSectionExtendedBy();
+		auto extendedBy = (savedValue == -1)
+			? layout.thirdWidth
+			: savedValue;
 		auto newBodyWidth = noResize
 			? layout.bodyWidth
-			: (layout.bodyWidth - layout.thirdWidth);
+			: (layout.bodyWidth - extendedBy);
 		auto currentRatio = Auth().data().dialogsWidthRatio();
-		Auth().data().setDialogsWidthRatio((currentRatio * layout.bodyWidth) / newBodyWidth);
+		Auth().data().setDialogsWidthRatio(
+			(currentRatio * layout.bodyWidth) / newBodyWidth);
 		newWindowSize = QSize(
 			window()->width() + (newBodyWidth - layout.bodyWidth),
 			window()->height());