sola/qwindowkit.git

			@@ -1,46 +1,130 @@
			#include "widgetwindowagent_p.h"

			#include <QtCore/QDebug>
			#include <QtCore/QDateTime>
			#include <QtGui/QPainter>

			#include <QWKCore/private/eventobserver_p.h>
			#include <QWKCore/qwindowkit_windows.h>

			namespace QWK {

			class WidgetBorderHandler : public QObject, public EventObserver {
			Q_OBJECT
			#if QWINDOWKIT_CONFIG(ENABLE_WINDOWS_SYSTEM_BORDERS)
			// https://github.com/qt/qtbase/blob/e26a87f1ecc40bc8c6aa5b889fce67410a57a702/src/plugins/platforms/windows/qwindowsbackingstore.cpp#L42
			// In QtWidgets applications, when repainting happens, QPA at the last calls
			// QWindowsBackingStore::flush() to draw the contents of the buffer to the screen, we need to
			// call GDI drawing the top border after that.

			// After debugging, we know that there are two situations that will lead to redrawing.
			//
			// 1. Windows sends a WM_PAINT message, after which Qt immediately generates a QExposeEvent or
			// QResizeEvent and send it to the corresponding QWidgetWindow instance, calling "flush" at the
			// end of its handler.
			//
			// 2. When a timer or user input triggers Qt to redraw spontaneously, the corresponding
			// QWidget receives a QEvent::UpdateRequest event and also calls "flush" at the end of its
			// handler.
			//
			// The above two cases are mutually exclusive, so we just need to intercept the two events
			// separately and draw the border area after the "flush" is called.

			// https://github.com/qt/qtbase/blob/e26a87f1ecc40bc8c6aa5b889fce67410a57a702/src/plugins/platforms/windows/qwindowswindow.cpp#L2440
			// Note that we can not draw the border right after WM_PAINT comes or right before the WndProc
			// returns, because Qt calls BeginPaint() and EndPaint() itself. We should make sure that we
			// draw the top border between these two calls, otherwise some display exceptions may arise.

			class WidgetBorderHandler : public QObject, public NativeEventFilter, public SharedEventFilter {
			public:
			explicit WidgetBorderHandler(QWidget widget, AbstractWindowContext ctx,
			QObject *parent = nullptr)
			: QObject(parent), widget(widget), ctx(ctx) {
			widget->installEventFilter(this);

			ctx->addObserver(this);
			// https://github.com/microsoft/terminal/blob/71a6f26e6ece656084e87de1a528c4a8072eeabd/src/cascadia/WindowsTerminal/NonClientIslandWindow.cpp#L940
			// Must extend top frame to client area
			static QVariant defaultMargins = QVariant::fromValue(QMargins(0, 1, 0, 0));
			ctx->setWindowAttribute(QStringLiteral("extra-margins"), defaultMargins);

			// Enable dark mode by default, otherwise the frame borders are white
			ctx->setWindowAttribute(QStringLiteral("dark-mode"), true);

			ctx->installNativeEventFilter(this);
			ctx->installSharedEventFilter(this);

			updateGeometry();
			}

			void updateGeometry() {
			if (widget->windowState() & (Qt::WindowMaximized \| Qt::WindowFullScreen)) {
			widget->setContentsMargins({});
			inline bool isNormalWindow() const {
			return !(widget->windowState() &
			(Qt::WindowMinimized \| Qt::WindowMaximized \| Qt::WindowFullScreen));
			}

			inline void updateGeometry() {
			if (isNormalWindow()) {
			widget->setContentsMargins(
			{0, ctx->windowAttribute(QStringLiteral("border-thickness")).toInt(), 0, 0});
			} else {
			widget->setContentsMargins({
			0,
			ctx->property("borderThickness").toInt(),
			0,
			0,
			});
			widget->setContentsMargins({});
			}
			}

			inline void resumeWidgetEvent(QWidget w, QEvent event) {
			// Friend class helping to call `event`
			class HackedWidget : public QWidget {
			public:
			friend class QWK::WidgetBorderHandler;
			};

			// Let the widget paint first
			static_cast<HackedWidget *>(w)->event(event);

			// Due to the timer or user action, Qt will redraw some regions spontaneously,
			// even if there is no WM_PAINT message, we must wait for it to finish redrawing
			// and then update the top border area.
			ctx->virtual_hook(AbstractWindowContext::DrawWindows10BorderHook2, nullptr);
			}

			inline void resumeWindowEvent(QWindow window, QEvent event) {
			// Friend class helping to call `event`
			class HackedWindow : public QWindow {
			public:
			friend class QWK::WidgetBorderHandler;
			};

			// Let Qt paint first
			static_cast<HackedWindow *>(window)->event(event);

			// Upon receiving the WM_PAINT message, Qt will redraw the entire view, and we
			// must wait for it to finish redrawing before drawing this top border area.
			ctx->virtual_hook(AbstractWindowContext::DrawWindows10BorderHook2, nullptr);
			}

			protected:
			bool observe(QEvent *event) override {
			switch (event->type()) {
			case QEvent::UpdateLater: {
			widget->update();
			bool nativeEventFilter(const QByteArray &eventType, void *message,
			QT_NATIVE_EVENT_RESULT_TYPE *result) override {
			Q_UNUSED(eventType)
			const auto msg = static_cast<const MSG *>(message);
			switch (msg->message) {
			case WM_DPICHANGED: {
			updateGeometry();
			break;
			}

			case QEvent::ScreenChangeInternal: {
			updateGeometry();
			case WM_ACTIVATE: {
			if (LOWORD(msg->wParam) == WA_INACTIVE) {
			// https://github.com/microsoft/terminal/blob/71a6f26e6ece656084e87de1a528c4a8072eeabd/src/cascadia/WindowsTerminal/NonClientIslandWindow.cpp#L904
			// When the window is inactive, there is a transparency bug in the top
			// border, and we need to extend the non-client area to the whole title
			// bar.
			QRect frame =
			ctx->windowAttribute(QStringLiteral("title-bar-rect")).toRect();
			QMargins margins{0, -frame.top(), 0, 0};
			ctx->setWindowAttribute(QStringLiteral("extra-margins"),
			QVariant::fromValue(margins));
			} else {
			// Restore margins when the window is active
			static QVariant defaultMargins = QVariant::fromValue(QMargins(0, 1, 0, 0));
			ctx->setWindowAttribute(QStringLiteral("extra-margins"), defaultMargins);
			}
			break;
			}

			@@ -50,23 +134,36 @@
			return false;
			}

			bool sharedEventFilter(QObject obj, QEvent event) override {
			Q_UNUSED(obj)

			auto window = widget->windowHandle();

			// Qt will absolutely send a QExposeEvent or QResizeEvent to the QWindow when it
			// receives a WM_PAINT message. When the control flow enters the expose handler, Qt
			// must have already called BeginPaint() and it's the best time for us to draw the
			// top border.

			// Since a QExposeEvent will be sent immediately after the QResizeEvent, we can simply
			// ignore it.
			if (event->type() == QEvent::Expose) {
			auto ee = static_cast<QExposeEvent *>(event);
			if (window->isExposed() && isNormalWindow() && !ee->region().isNull()) {
			resumeWindowEvent(window, event);
			return true;
			}
			}

			return false;
			}

			bool eventFilter(QObject obj, QEvent event) override {
			Q_UNUSED(obj)
			switch (event->type()) {
			case QEvent::Paint: {
			if (widget->windowState() & (Qt::WindowMaximized \| Qt::WindowFullScreen))
			case QEvent::UpdateRequest: {
			if (!isNormalWindow())
			break;

			auto paintEvent = static_cast<QPaintEvent *>(event);
			auto rect = paintEvent->rect();
			auto region = paintEvent->region();

			QPainter painter(widget);
			void *args[] = {
			&painter,
			&rect,
			&region,
			};
			ctx->virtual_hook(AbstractWindowContext::DrawWindows10BorderHook, args);
			resumeWidgetEvent(widget, event);
			return true;
			}

			@@ -94,11 +191,10 @@
			void WidgetWindowAgentPrivate::setupWindows10BorderWorkaround() {
			// Install painting hook
			auto ctx = context.get();
			if (ctx->property("needBorderPainter").toBool()) {
			std::ignore = new WidgetBorderHandler(hostWidget, ctx, ctx);
			if (ctx->windowAttribute(QStringLiteral("win10-border-needed")).toBool()) {
			borderHandler = std::make_unique<WidgetBorderHandler>(hostWidget, ctx);
			}
			}
			#endif

			}

			#include "widgetwindowagent_win.moc"