Sine Striker
2024-01-01 8517f5b133f1aceff893a1a01417157136fe0715
src/widgets/widgetwindowagent_win.cpp
@@ -1,3 +1,6 @@
// Copyright (C) 2023-2024 Stdware Collections
// SPDX-License-Identifier: Apache-2.0
#include "widgetwindowagent_p.h"
#include <QtCore/QDebug>
@@ -5,6 +8,7 @@
#include <QtGui/QPainter>
#include <QWKCore/qwindowkit_windows.h>
#include <QWKCore/private/qwkglobal_p.h>
namespace QWK {
@@ -14,13 +18,13 @@
    // 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.
    // After debugging, we know that there are two situations that will lead to repaint.
    //
    // 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
    // 2. When a timer or user input triggers Qt to repaint spontaneously, the corresponding
    // QWidget receives a QEvent::UpdateRequest event and also calls "flush" at the end of its
    // handler.
    //
@@ -44,7 +48,7 @@
            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
            // Enable dark mode by default, otherwise the system borders are white
            ctx->setWindowAttribute(QStringLiteral("dark-mode"), true);
            ctx->installNativeEventFilter(this);
@@ -67,64 +71,57 @@
            }
        }
        inline void resumeWidgetEvent(QWidget *w, QEvent *event) {
            // Friend class helping to call `event`
            class HackedWidget : public QWidget {
            public:
                friend class QWK::WidgetBorderHandler;
            };
        inline void resumeWidgetEventAndDraw(QWidget *w, QEvent *event) {
            // Let the widget paint first
            static_cast<HackedWidget *>(w)->event(event);
            Private::ObjectHelper::sendEvent(w, 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
            // Due to the timer or user action, Qt will repaint some regions spontaneously,
            // even if there is no WM_PAINT message, we must wait for it to finish painting
            // 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;
            };
        inline void resumeWindowEventAndDraw(QWindow *window, QEvent *event) {
            // Let Qt paint first
            static_cast<HackedWindow *>(window)->event(event);
            Private::ObjectHelper::sendEvent(window, 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.
            // Upon receiving the WM_PAINT message, Qt will repaint the entire view, and we
            // must wait for it to finish painting before drawing this top border area.
            ctx->virtual_hook(AbstractWindowContext::DrawWindows10BorderHook2, nullptr);
        }
        inline void updateExtraMargins(bool windowActive) {
            if (windowActive) {
                // Restore margins when the window is active
                static QVariant defaultMargins = QVariant::fromValue(QMargins(0, 1, 0, 0));
                ctx->setWindowAttribute(QStringLiteral("extra-margins"), defaultMargins);
                return;
            }
            // 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("window-rect")).toRect();
            QMargins margins{0, -frame.top(), 0, 0};
            ctx->setWindowAttribute(QStringLiteral("extra-margins"), QVariant::fromValue(margins));
        }
    protected:
        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();
                    updateExtraMargins(widget->isActiveWindow());
                    break;
                }
                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);
                    }
                    updateExtraMargins(LOWORD(msg->wParam) != WA_INACTIVE);
                    break;
                }
@@ -149,7 +146,7 @@
            if (event->type() == QEvent::Expose) {
                auto ee = static_cast<QExposeEvent *>(event);
                if (window->isExposed() && isNormalWindow() && !ee->region().isNull()) {
                    resumeWindowEvent(window, event);
                    resumeWindowEventAndDraw(window, event);
                    return true;
                }
            }
@@ -159,11 +156,12 @@
        bool eventFilter(QObject *obj, QEvent *event) override {
            Q_UNUSED(obj)
            switch (event->type()) {
                case QEvent::UpdateRequest: {
                    if (!isNormalWindow())
                        break;
                    resumeWidgetEvent(widget, event);
                    resumeWidgetEventAndDraw(widget, event);
                    return true;
                }