Adjust paint event handler

Sine Striker

2023-12-23 f3721da17996168489778327459084dd227690d6

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#include "widgetwindowagent_p.h"
 
#include <QtGui/QPainter>
 
#include <QWKCore/qwindowkit_windows.h>
#include <QWKCore/qwkconfig.h>
#include <QWKCore/private/nativeeventfilter_p.h>
 
namespace QWK {
 
#if QWINDOWKIT_CONFIG(ENABLE_WINDOWS_SYSTEM_BORDER)
 
    class WidgetBorderHandler;
 
    class WidgetBorderHandler : public QObject, public NativeEventFilter {
    public:
        explicit WidgetBorderHandler(QWidget *widget, AbstractWindowContext *ctx)
            : QObject(ctx), widget(widget), ctx(ctx) {
            widget->installEventFilter(this);
 
            ctx->installNativeEventFilter(this);
            updateGeometry();
        }
 
        void updateGeometry() {
            if (widget->windowState() & (Qt::WindowMaximized | Qt::WindowFullScreen)) {
                widget->setContentsMargins({});
            } else {
                widget->setContentsMargins({
                    0,
                    ctx->property("borderThickness").toInt(),
                    0,
                    0,
                });
            }
        }
 
    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();
                    break;
                }
 
                case WM_THEMECHANGED:
                case WM_SYSCOLORCHANGE:
                case WM_DWMCOLORIZATIONCOLORCHANGED: {
                    widget->update();
                    break;
                }
 
                case WM_SETTINGCHANGE: {
                    if (!msg->wParam && msg->lParam &&
                        std::wcscmp(reinterpret_cast<LPCWSTR>(msg->lParam), L"ImmersiveColorSet") ==
                            0) {
                        widget->update();
                    }
                    break;
                }
 
                default:
                    break;
            }
            return false;
        }
 
        bool eventFilter(QObject *obj, QEvent *event) override {
            Q_UNUSED(obj)
            switch (event->type()) {
                case QEvent::Paint: {
                    if (widget->windowState() &
                        (Qt::WindowMinimized | Qt::WindowMaximized | Qt::WindowFullScreen))
                        break;
 
                    // Friend class helping to call `event`
                    class HackedWidget : public QWidget {
                    public:
                        friend class WidgetBorderHandler;
                    };
 
                    // Let the widget paint first
                    static_cast<HackedWidget *>(widget)->event(event);
 
                    // Draw border
                    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);
                    return true;
                }
 
                case QEvent::WindowStateChange: {
                    updateGeometry();
                    break;
                }
 
                case QEvent::WindowActivate:
                case QEvent::WindowDeactivate: {
                    widget->update();
                    break;
                }
 
                default:
                    break;
            }
            return false;
        }
 
        QWidget *widget;
        AbstractWindowContext *ctx;
    };
#endif
 
    void WidgetWindowAgentPrivate::setupWindows10BorderWorkaround() {
#if QWINDOWKIT_CONFIG(ENABLE_WINDOWS_SYSTEM_BORDER)
        // Install painting hook
        auto ctx = context.get();
        if (ctx->property("needBorderPainter").toBool()) {
            std::ignore = new WidgetBorderHandler(hostWidget, ctx);
        }
#endif
    }
 
}