feat(Screenshot): Add Freedesktop portal screenshot support.

This uses the system implementation of a screenshot grabber, which works
in sandboxes and on wayland. On systems with a desktop environment, this
will fix issues with dual-screen, wayland, and Flatpak. On more
barebones systems, this should make no difference.

CMakeLists.txt

@@ -447,6 +447,9 @@ set(${PROJECT_NAME}_SOURCES
     src/platform/desktop_notifications/desktopnotifybackend.h
     src/platform/posixsignalnotifier.cpp
     src/platform/posixsignalnotifier.h
+    src/platform/screenshot_dbus.cpp
+    src/platform/screenshot.cpp
+    src/platform/screenshot.h
     src/platform/stacktrace.cpp
     src/platform/stacktrace.h
     src/platform/timer.h
@@ -578,6 +581,8 @@ set(${PROJECT_NAME}_SOURCES
     src/widget/splitterrestorer.h
     src/widget/style.cpp
     src/widget/style.h
+    src/widget/tool/abstractscreenshotgrabber.cpp
+    src/widget/tool/abstractscreenshotgrabber.h
     src/widget/tool/activatedialog.cpp
     src/widget/tool/activatedialog.h
     src/widget/tool/adjustingscrollarea.cpp

src/BUILD.bazel

@@ -60,6 +60,7 @@ qt_moc(
         "platform/desktop_notifications/desktopnotify.h",
         "platform/desktop_notifications/desktopnotifybackend.h",
         "platform/posixsignalnotifier.h",
+        "platform/screenshot_dbus.h",
         "video/camerasource.h",
         "video/corevideosource.h",
         "video/netcamview.h",
@@ -110,6 +111,7 @@ qt_moc(
         "widget/qrwidget.h",
         "widget/searchform.h",
         "widget/style.h",
+        "widget/tool/abstractscreenshotgrabber.h",
         "widget/tool/activatedialog.h",
         "widget/tool/adjustingscrollarea.h",
         "widget/tool/callconfirmwidget.h",

src/platform/screenshot.cpp

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright © 2025 The TokTok team.
+ */
+
+#include "screenshot.h"
+
+#include "screenshot_dbus.h"
+#include "src/widget/tool/abstractscreenshotgrabber.h"
+
+AbstractScreenshotGrabber* Platform::createScreenshotGrabber(QWidget* parent)
+{
+#if QT_CONFIG(dbus)
+    return DBusScreenshotGrabber::create(parent);
+#else
+    std::ignore = parent;
+    return nullptr;
+#endif
+}

src/platform/screenshot.h

@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright © 2025 The TokTok team.
+ */
+
+#pragma once
+
+class AbstractScreenshotGrabber;
+class QWidget;
+
+namespace Platform {
+/**
+ * @brief Create a platform-dependent screenshot grabber.
+ *
+ * If no platform-specific screenshot grabber is available, this function returns nullptr.
+ * The caller should then create a default screenshot grabber.
+ *
+ * @param parent The parent widget for the screenshot grabber.
+ */
+AbstractScreenshotGrabber* createScreenshotGrabber(QWidget* parent);
+} // namespace Platform

src/platform/screenshot_dbus.cpp

@@ -0,0 +1,162 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright © 2025 The TokTok team.
+ */
+
+#include "screenshot_dbus.h"
+
+#include <QtGlobal>
+
+#if QT_CONFIG(dbus)
+#include <QDBusConnection>
+#include <QDBusInterface>
+#include <QDBusMessage>
+#include <QDebug>
+#include <QGuiApplication>
+#include <QPixmap>
+#include <QRect>
+#include <QUrl>
+#include <QWidget>
+
+#include <memory>
+
+namespace {
+const QString PORTAL_DBUS_NAME = QStringLiteral("org.freedesktop.portal.Desktop");
+const QString PORTAL_DBUS_CORE_OBJECT = QStringLiteral("/org/freedesktop/portal/desktop");
+const QString PORTAL_DBUS_REQUEST_INTERFACE = QStringLiteral("org.freedesktop.portal.Request");
+const QString PORTAL_DBUS_SCREENSHOT_INTERFACE =
+    QStringLiteral("org.freedesktop.portal.Screenshot");
+
+QString winIdString(WId winId)
+{
+    // If we're wayland, return wayland:$id.
+    if (QGuiApplication::platformName() == QStringLiteral("wayland")) {
+        return QStringLiteral("wayland:%1").arg(winId);
+    }
+    if (QGuiApplication::platformName() == QStringLiteral("xcb")) {
+        return QStringLiteral("x11:0x%1").arg(winId, 0, 16);
+    }
+    qWarning() << "Unknown platform:" << QGuiApplication::platformName() << "cannot take screenshots";
+    return {};
+}
+} // namespace
+
+struct DBusScreenshotGrabber::Data
+{
+    QDBusInterface portal;
+    WId winId;
+    QString path;
+
+    explicit Data(QWidget* parent)
+        : portal(PORTAL_DBUS_NAME, PORTAL_DBUS_CORE_OBJECT, PORTAL_DBUS_SCREENSHOT_INTERFACE,
+                 QDBusConnection::sessionBus(), parent)
+        , winId{parent->topLevelWidget()->winId()}
+    {
+    }
+
+    QString grabScreen()
+    {
+        if (!portal.connection().isConnected()) {
+            qWarning() << "DBus connection failed";
+            return {};
+        }
+
+        if (!portal.isValid()) {
+            qWarning() << "Failed to connect to org.freedesktop.portal.Screenshot";
+            return {};
+        }
+
+        const QString wid = winIdString(winId);
+        if (wid.isEmpty()) {
+            return {};
+        }
+
+        const QDBusMessage reply = portal.call(QStringLiteral("Screenshot"), wid,
+                                               QVariantMap{
+                                                   {"modal", true},
+                                                   {"interactive", true},
+                                                   {"handle_token", "1"},
+                                               });
+
+        if (reply.type() == QDBusMessage::ErrorMessage) {
+            qWarning() << "Failed to take screenshot:" << reply.errorMessage();
+            return {};
+        }
+
+        return reply.arguments().value(0).value<QDBusObjectPath>().path();
+    }
+};
+
+DBusScreenshotGrabber::DBusScreenshotGrabber(QWidget* parent)
+    : AbstractScreenshotGrabber(parent)
+    , d(std::make_unique<Data>(parent))
+{
+}
+
+DBusScreenshotGrabber::~DBusScreenshotGrabber() = default;
+
+DBusScreenshotGrabber* DBusScreenshotGrabber::create(QWidget* parent)
+{
+    auto grabber = std::make_unique<DBusScreenshotGrabber>(parent);
+    if (!grabber->isValid()) {
+        return nullptr;
+    }
+
+    const QString path = grabber->d->grabScreen();
+    if (path.isEmpty()) {
+        // Some connection problem or unsupported platform. We're not trying this again.
+        return nullptr;
+    }
+
+    qDebug() << "Opened screenshot dialog; waiting for response on" << path;
+    QDBusConnection::sessionBus().connect(
+        // org.freedesktop.portal.Request::Response
+        PORTAL_DBUS_NAME, path, PORTAL_DBUS_REQUEST_INTERFACE, QStringLiteral("Response"),
+        grabber.get(), SLOT(screenshotResponse(uint, QVariantMap)));
+
+    return grabber.release();
+}
+
+bool DBusScreenshotGrabber::isValid() const
+{
+    return d->portal.isValid();
+}
+
+void DBusScreenshotGrabber::showGrabber()
+{
+    // Nothing to do here. We've done everything in create().
+}
+
+/**
+ * https://docs.flatpak.org/en/latest/portal-api-reference.html#gdbus-signal-org-freedesktop-portal-Request.Response
+ *
+ * Emitted when the user interaction for a portal request is over.
+ *
+ * The response indicates how the user interaction ended:
+ *
+ * 0: Success, the request is carried out
+ * 1: The user cancelled the interaction
+ * 2: The user interaction was ended in some other way
+ */
+void DBusScreenshotGrabber::screenshotResponse(uint response, QVariantMap results)
+{
+    switch (response) {
+    case 0: {
+        const QUrl uri{results[QStringLiteral("uri")].toString()};
+        qDebug() << "Screenshot taken:" << uri.toString();
+        emit screenshotTaken(QPixmap(uri.toLocalFile()));
+        break;
+    }
+    case 1:
+        qDebug() << "User cancelled screenshot request";
+        emit rejected();
+        break;
+    default:
+        qWarning() << "Screenshot request failed:" << response;
+        emit rejected();
+        break;
+    }
+
+    // We're done, clean up.
+    deleteLater();
+}
+#endif // QT_CONFIG(dbus)

src/platform/screenshot_dbus.h

@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright © 2025 The TokTok team.
+ */
+
+#pragma once
+
+#include "src/widget/tool/abstractscreenshotgrabber.h"
+
+#include <QVariantMap>
+
+#include <memory>
+
+#if QT_CONFIG(dbus)
+/** @brief Grabs screenshot using org.freedesktop.portal.Screenshot.
+ *
+ * https://docs.flatpak.org/en/latest/portal-api-reference.html#gdbus-org.freedesktop.portal.Screenshot
+ */
+class DBusScreenshotGrabber : public AbstractScreenshotGrabber
+{
+    Q_OBJECT
+
+public:
+    // Don't use these directly, use create() instead.
+    explicit DBusScreenshotGrabber(QWidget* parent);
+    ~DBusScreenshotGrabber() override;
+
+    // Create a screenshot grabber. Returns nullptr if no DBus connection could be established.
+    static DBusScreenshotGrabber* create(QWidget* parent);
+
+    bool isValid() const;
+    void showGrabber() override;
+
+private slots:
+    void screenshotResponse(uint response, QVariantMap results);
+
+private:
+    struct Data;
+    std::unique_ptr<Data> d;
+};
+#endif // QT_CONFIG(dbus)

src/widget/form/chatform.cpp

@@ -4,7 +4,6 @@
  */
 
 #include "chatform.h"
-#include "src/chatlog/chatlinecontentproxy.h"
 #include "src/chatlog/chatmessage.h"
 #include "src/chatlog/chatwidget.h"
 #include "src/chatlog/content/filetransferwidget.h"
@@ -16,17 +15,17 @@
 #include "src/model/status.h"
 #include "src/nexus.h"
 #include "src/persistence/history.h"
-#include "src/persistence/offlinemsgengine.h"
 #include "src/persistence/profile.h"
 #include "src/persistence/settings.h"
+#include "src/platform/screenshot.h"
 #include "src/video/netcamview.h"
 #include "src/widget/chatformheader.h"
 #include "src/widget/contentdialogmanager.h"
 #include "src/widget/form/loadhistorydialog.h"
 #include "src/widget/imagepreviewwidget.h"
-#include "src/widget/maskablepixmapwidget.h"
 #include "src/widget/searchform.h"
 #include "src/widget/style.h"
+#include "src/widget/tool/abstractscreenshotgrabber.h"
 #include "src/widget/tool/callconfirmwidget.h"
 #include "src/widget/tool/chattextedit.h"
 #include "src/widget/tool/croppinglabel.h"
@@ -36,6 +35,7 @@
 
 #include <QApplication>
 #include <QClipboard>
+#include <QDragEnterEvent>
 #include <QFileDialog>
 #include <QFileInfo>
 #include <QMessageBox>
@@ -567,11 +567,14 @@ void ChatForm::onScreenshotClicked()
     QTimer::singleShot(SCREENSHOT_GRABBER_OPENING_DELAY, this, &ChatForm::hideFileMenu);
 }
 
-void ChatForm::doScreenshot() const
+void ChatForm::doScreenshot()
 {
-    // note: grabber is self-managed and will destroy itself when done
-    ScreenshotGrabber* grabber = new ScreenshotGrabber;
-    connect(grabber, &ScreenshotGrabber::screenshotTaken, this, &ChatForm::previewImage);
+    // Note: grabber is self-managed and will destroy itself when done.
+    AbstractScreenshotGrabber* grabber = Platform::createScreenshotGrabber(this);
+    if (grabber == nullptr) {
+        grabber = new ScreenshotGrabber(this);
+    }
+    connect(grabber, &AbstractScreenshotGrabber::screenshotTaken, this, &ChatForm::previewImage);
     grabber->showGrabber();
 }
 

src/widget/form/chatform.h

@@ -16,7 +16,6 @@
 #include "src/model/status.h"
 #include "src/persistence/history.h"
 #include "src/video/netcamview.h"
-#include "src/widget/tool/screenshotgrabber.h"
 
 class CallConfirmWidget;
 class ContentDialogManager;
@@ -97,7 +96,7 @@ private slots:
     void previewImage(const QPixmap& pixmap);
     void cancelImagePreview();
     void sendImageFromPreview();
-    void doScreenshot() const;
+    void doScreenshot();
     void onCopyStatusMessage();
 
     void callUpdateFriendActivity();

src/widget/form/settings/avform.cpp

@@ -194,8 +194,11 @@ void AVForm::on_videoModesComboBox_currentIndexChanged(int index)
             open(devName, mode);
         };
 
-        // note: grabber is self-managed and will destroy itself when done
-        ScreenshotGrabber* screenshotGrabber = new ScreenshotGrabber;
+        // We're not using the platform-specific grabber here, because all we want is a rectangle
+        // selection. We don't actually need a screenshot to be taken.
+        //
+        // Note: grabber is self-managed and will destroy itself when done.
+        ScreenshotGrabber* screenshotGrabber = new ScreenshotGrabber(this);
 
         connect(screenshotGrabber, &ScreenshotGrabber::regionChosen, this, onGrabbed,
                 Qt::QueuedConnection);

src/widget/tool/abstractscreenshotgrabber.cpp

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later
+ * Copyright © 2015-2019 by The qTox Project Contributors
+ * Copyright © 2024-2025 The TokTok team.
+ */
+
+#include "abstractscreenshotgrabber.h"
+
+AbstractScreenshotGrabber::AbstractScreenshotGrabber(QObject* parent)
+    : QObject(parent)
+{
+}
+
+AbstractScreenshotGrabber::~AbstractScreenshotGrabber() = default;