Windows: Global "take screenshot" shortcut (flameshot-org#4556)

* Enable QHotkey on Windows to define global shortcut for taking screenshot

* Check if Windows forces PrntScr for its snipping tool; provide the option to change corresponding registry key by Flameshot

* Option to register Flameshot as MS-SCREENCLIP application

* clang-format

* Default shortcut

* Minor: Move MsScreenclip initialization to separate function

* Minor: Move MsScreenclip initialization to separate function

Author: ElTh0r0

CMakeLists.txt

@@ -20,6 +20,10 @@ set(QT_DEFAULT_MAJOR_VERSION 6 CACHE STRING "")
 set(QT_VERSION_MAJOR 6 CACHE STRING "")
 #BUILD_SHARED_LIBS used by QHotkey and QtColorWidgets
 option(BUILD_SHARED_LIBS OFF)
+#QHOTKEY_INSTALL used by QHotkey; must be disabled on Windows
+if(WIN32)
+set(QHOTKEY_INSTALL OFF CACHE BOOL "qHotkey install")
+endif()
 
 #Needed due to linker error with QtColorWidget
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
@@ -134,7 +138,7 @@ endif()
 # ToDo: Check if this is used anywhere
 option(BUILD_STATIC_LIBS ON)
 
-if(APPLE)
+if(WIN32 OR APPLE)
   FetchContent_Declare(
     qHotKey
     GIT_REPOSITORY https://github.com/flameshot-org/QHotkey

README.md

@@ -237,9 +237,9 @@ These shortcuts are available in GUI mode:
 
 ### Global
 
-Flameshot uses <kbd>Print screen</kbd> (Windows) and <kbd>cmd</kbd>-<kbd>shift</kbd>-<kbd>x</kbd> (macOS) as default global hotkeys.
-
-On Linux, Flameshot doesn't yet support <kbd>Prt Sc</kbd> out of the box, but with a bit of configuration you can set this up:
+- Windows: <kbd>Prt Sc</kbd> (fixed, cannot be changed) and <kbd>Win</kbd> + <kbd>Shift</kbd> + <kbd>X</kbd> (can be changed in the settings)
+- macOS: <kbd>cmd</kbd> + <kbd>Shift</kbd> + <kbd>X</kbd> (can be changed in the settings)
+- Linux: Flameshot doesn't yet support <kbd>Prt Sc</kbd> out of the box, but you can set this up with a bit of configuration:
 
 #### On KDE Plasma desktop
 

src/CMakeLists.txt

@@ -296,6 +296,11 @@ if (WIN32)
     if (NOT USE_OPENSSL)
         message(WARNING "OpenSSL is required to upload screenshots")
     endif ()
+
+    target_link_libraries(
+            flameshot
+            qhotkey
+    )
 endif ()
 
 # Choose default color palette (small or large)

src/config/setshortcutwidget.cpp

@@ -8,6 +8,7 @@
 #include <QLabel>
 #include <QLayout>
 #include <QPixmap>
+#include <QTimer>
 
 SetShortcutDialog::SetShortcutDialog(QDialog* parent,
                                      const QString& shortcutName)
@@ -34,7 +35,7 @@ SetShortcutDialog::SetShortcutDialog(QDialog* parent,
     m_layout->addWidget(infoIcon);
 
     QString msg = "";
-#if defined(Q_OS_MAC)
+#if defined(Q_OS_MACOS)
     msg = tr(
       "Press Esc to cancel or ⌘+Backspace to disable the keyboard shortcut.");
 #else
@@ -58,6 +59,15 @@ SetShortcutDialog::SetShortcutDialog(QDialog* parent,
     infoBottom->setMargin(10);
     infoBottom->setAlignment(Qt::AlignCenter);
     m_layout->addWidget(infoBottom);
+
+    // 0ms Delay: Event loop waits until after show(); widget fully initialized
+    QTimer::singleShot(0, this, &SetShortcutDialog::startCapture);
+}
+
+void SetShortcutDialog::startCapture()
+{
+    grabKeyboard(); // Call AFTER show()!
+    setFocus();
 }
 
 const QKeySequence& SetShortcutDialog::shortcut()
@@ -67,16 +77,19 @@ const QKeySequence& SetShortcutDialog::shortcut()
 
 void SetShortcutDialog::keyPressEvent(QKeyEvent* ke)
 {
-    if (ke->modifiers() & Qt::ShiftModifier) {
+    Qt::KeyboardModifiers mods = ke->modifiers();
+
+    if (mods & Qt::ShiftModifier) {
         m_modifier += "Shift+";
     }
-    if (ke->modifiers() & Qt::ControlModifier) {
+    if (mods & Qt::ControlModifier) {
         m_modifier += "Ctrl+";
     }
-    if (ke->modifiers() & Qt::AltModifier) {
+    if (mods & Qt::AltModifier) {
         m_modifier += "Alt+";
     }
-    if (ke->modifiers() & Qt::MetaModifier) {
+    // ke->key() == Qt::Key_Meta required on Windows to grab Win key
+    if (ke->modifiers() & Qt::MetaModifier || ke->key() == Qt::Key_Meta) {
         m_modifier += "Meta+";
     }
 
@@ -91,3 +104,15 @@ void SetShortcutDialog::keyReleaseEvent(QKeyEvent* event)
     }
     accept();
 }
+
+void SetShortcutDialog::accept()
+{
+    releaseKeyboard();
+    QDialog::accept();
+}
+
+void SetShortcutDialog::reject()
+{
+    releaseKeyboard();
+    QDialog::reject();
+}

src/config/setshortcutwidget.h

@@ -19,12 +19,16 @@ class SetShortcutDialog : public QDialog
     const QKeySequence& shortcut();
 
 public:
-    void keyPressEvent(QKeyEvent*);
-    void keyReleaseEvent(QKeyEvent* event);
+    void keyPressEvent(QKeyEvent*) override;
+    void keyReleaseEvent(QKeyEvent* event) override;
 
-signals:
+private slots:
+    void accept() override;
+    void reject() override;
 
 private:
+    void startCapture();
+
     QVBoxLayout* m_layout;
     QString m_modifier;
     QKeySequence m_ks;

src/config/shortcutswidget.cpp

@@ -7,11 +7,14 @@
 #include "src/core/qguiappcurrentscreen.h"
 #include "src/utils/globalvalues.h"
 #include "toolfactory.h"
+#include <QCheckBox>
 #include <QCursor>
+#include <QDir>
 #include <QHeaderView>
 #include <QIcon>
 #include <QKeyEvent>
 #include <QLabel>
+#include <QMessageBox>
 #include <QRect>
 #include <QScreen>
 #include <QStringList>
@@ -34,11 +37,20 @@ ShortcutsWidget::ShortcutsWidget(QWidget* parent)
     m_layout = new QVBoxLayout(this);
     m_layout->setAlignment(Qt::AlignHCenter | Qt::AlignVCenter);
 
+#if defined(Q_OS_WIN)
+    checkPrintScreenForcesSnipping();
+#endif
+
     initInfoTable();
     connect(ConfigHandler::getInstance(),
             &ConfigHandler::fileChanged,
             this,
             &ShortcutsWidget::populateInfoTable);
+
+#if defined(Q_OS_WIN)
+    initMsScreenclipCheckbox();
+#endif
+
     show();
 }
 
@@ -202,13 +214,15 @@ void ShortcutsWidget::loadShortcuts()
     appendShortcut("SCREENSHOT_HISTORY", tr("Screenshot history"));
 #endif
 #elif defined(Q_OS_WIN)
-
+    if (this->isPrintScreenKeyForSnippingDisabled()) {
+        m_shortcuts << (QStringList() << "" << QObject::tr("Capture screen")
+                                      << "Print Screen");
+    }
+    appendShortcut("TAKE_SCREENSHOT", tr("Capture screen"));
 #ifdef ENABLE_IMGUR
     m_shortcuts << (QStringList() << "" << QObject::tr("Screenshot history")
                                   << "Shift+Print Screen");
 #endif
-    m_shortcuts << (QStringList()
-                    << "" << QObject::tr("Capture screen") << "Print Screen");
 #else
     // TODO - Linux doesn't support global shortcuts for (XServer and Wayland),
     // possibly it will be solved in the QHotKey library later. So it is
@@ -241,3 +255,195 @@ const QString& ShortcutsWidget::nativeOSHotKeyText(const QString& text)
     return m_res;
 }
 #endif
+
+#if defined(Q_OS_WIN)
+void ShortcutsWidget::checkPrintScreenForcesSnipping()
+{
+    if (!isPrintScreenKeyForSnippingDisabled() &&
+        !ConfigHandler().ignorePrntScrForcesSnipping()) {
+        QMessageBox msgBox;
+        msgBox.setWindowTitle("Flameshot");
+        msgBox.setIcon(QMessageBox::Question);
+        msgBox.setText(tr("It seems, that Windows forces to open its screenshot"
+                          " tool when the 'Print Screen' key is pressed. Would "
+                          "you like to disable this so that Flameshot can use "
+                          "the 'Print Screen' key?") +
+                       "\n\n" +
+                       tr("Flameshot must be restarted for changes to take "
+                          "effect."));
+        QPushButton* yesBtn = msgBox.addButton(QMessageBox::Yes);
+        QPushButton* noBtn = msgBox.addButton(QMessageBox::No);
+        QPushButton* noDontAskAgainBtn =
+          new QPushButton(tr("No, don't ask again"));
+        msgBox.addButton(noDontAskAgainBtn, QMessageBox::RejectRole);
+        msgBox.setDefaultButton(yesBtn);
+        msgBox.exec();
+
+        if (msgBox.clickedButton() == yesBtn) {
+            if (!disablePrintScreenKeyForSnipping()) {
+                QMessageBox::warning(
+                  this, "Flameshot", tr("The registry could not be changed!"));
+            }
+        } else if (msgBox.clickedButton() == noDontAskAgainBtn) {
+            ConfigHandler().setIgnorePrntScrForcesSnipping(true);
+        }
+    }
+}
+
+bool ShortcutsWidget::isPrintScreenKeyForSnippingDisabled()
+{
+    QSettings PrintKeyForSnipping("HKEY_CURRENT_USER\\Control Panel\\Keyboard",
+                                  QSettings::NativeFormat);
+    return PrintKeyForSnipping.value("PrintScreenKeyForSnippingEnabled", 1)
+             .toInt() == 0;
+}
+
+bool ShortcutsWidget::disablePrintScreenKeyForSnipping()
+{
+    QSettings PrintKeyForSnipping("HKEY_CURRENT_USER\\Control Panel\\Keyboard",
+                                  QSettings::NativeFormat);
+    PrintKeyForSnipping.setValue("PrintScreenKeyForSnippingEnabled", 0);
+    PrintKeyForSnipping.sync();
+    if (QSettings::AccessError == PrintKeyForSnipping.status()) {
+        return false;
+    }
+    return this->isPrintScreenKeyForSnippingDisabled();
+}
+
+void ShortcutsWidget::initMsScreenclipCheckbox()
+{
+    m_registerMsScreenclip =
+      new QCheckBox(tr("Register Flameshot as MS-SCREENCLIP application "
+                       "(administrator privileges required)"),
+                    this);
+    m_registerMsScreenclip->setToolTip(
+      tr("After registering, you can select Flameshot as the default "
+         "screenshot application in Windows Settings."));
+    m_registerMsScreenclip->setChecked(isMsScreenclipRegistered());
+    m_layout->addWidget(m_registerMsScreenclip);
+
+    connect(
+      m_registerMsScreenclip, &QCheckBox::clicked, this, [this](bool checked) {
+          if (checked) {
+              if (!registerMsScreenclip()) {
+                  QMessageBox::warning(
+                    this,
+                    "Flameshot",
+                    tr("The registry could not be changed!") + "\n" +
+                      tr("You may start Flameshot as administrator ONCE and "
+                         "try again!"));
+                  m_registerMsScreenclip->setChecked(false);
+              }
+          } else {
+              if (!unregisterMsScreenclip()) {
+                  QMessageBox::warning(
+                    this,
+                    "Flameshot",
+                    tr("The registry could not be changed!") + "\n" +
+                      tr("You may start Flameshot as administrator ONCE and "
+                         "try again!"));
+                  m_registerMsScreenclip->setChecked(true);
+              }
+          }
+      });
+}
+
+bool ShortcutsWidget::isMsScreenclipRegistered()
+{
+    QSettings URLAssociations(
+      "HKEY_LOCAL_MACHINE\\SOFTWARE\\Flameshot\\Capabilities\\URLAssociations",
+      QSettings::NativeFormat);
+    QString value = URLAssociations.value("ms-screenclip", "").toString();
+    if (value.toLower() != "flameshot")
+        return false;
+
+    QSettings RegisteredApplications(
+      "HKEY_LOCAL_MACHINE\\SOFTWARE\\RegisteredApplications",
+      QSettings::NativeFormat);
+    value = RegisteredApplications.value("Flameshot", "").toString();
+    if (value.toLower() !=
+        QString("SOFTWARE\\Flameshot\\Capabilities").toLower())
+        return false;
+
+    QSettings FlameshotShellCmd(
+      "HKEY_CURRENT_USER\\Software\\Classes\\Flameshot\\Shell\\Open\\command",
+      QSettings::NativeFormat);
+    value = FlameshotShellCmd.value(".").toString();
+    if (value.toLower() != QString("\"" +
+                                   QDir::toNativeSeparators(
+                                     QCoreApplication::applicationFilePath()) +
+                                   "\" gui")
+                             .toLower())
+        return false;
+
+    return true; // All registry entries found
+}
+
+bool ShortcutsWidget::registerMsScreenclip()
+{
+    QSettings URLAssociations(
+      "HKEY_LOCAL_MACHINE\\SOFTWARE\\Flameshot\\Capabilities\\URLAssociations",
+      QSettings::NativeFormat);
+    URLAssociations.setValue("ms-screenclip", "Flameshot");
+    URLAssociations.sync();
+    if (QSettings::AccessError == URLAssociations.status()) {
+        return false;
+    }
+
+    QSettings RegisteredApplications(
+      "HKEY_LOCAL_MACHINE\\SOFTWARE\\RegisteredApplications",
+      QSettings::NativeFormat);
+    RegisteredApplications.setValue("Flameshot",
+                                    "SOFTWARE\\Flameshot\\Capabilities");
+    RegisteredApplications.sync();
+    if (QSettings::AccessError == RegisteredApplications.status()) {
+        return false;
+    }
+
+    QSettings FlameshotShellCmd(
+      "HKEY_CURRENT_USER\\Software\\Classes\\Flameshot\\Shell\\Open\\command",
+      QSettings::NativeFormat);
+    FlameshotShellCmd.setValue(
+      ".",
+      "\"" + QDir::toNativeSeparators(QCoreApplication::applicationFilePath()) +
+        "\" gui");
+    FlameshotShellCmd.sync();
+    if (QSettings::AccessError == FlameshotShellCmd.status()) {
+        return false;
+    }
+
+    return isMsScreenclipRegistered();
+}
+
+bool ShortcutsWidget::unregisterMsScreenclip()
+{
+    QSettings FlameshotShellCmd("HKEY_CURRENT_USER\\Software\\Classes",
+                                QSettings::NativeFormat);
+    FlameshotShellCmd.remove("Flameshot");
+    FlameshotShellCmd.sync();
+    if (QSettings::AccessError == FlameshotShellCmd.status()) {
+        return false;
+    }
+
+    QSettings RegisteredApplications(
+      "HKEY_LOCAL_MACHINE\\SOFTWARE\\RegisteredApplications",
+      QSettings::NativeFormat);
+    RegisteredApplications.remove("Flameshot");
+    RegisteredApplications.sync();
+    if (QSettings::AccessError == RegisteredApplications.status()) {
+        return false;
+    }
+
+    QSettings URLAssociations(
+      "HKEY_LOCAL_MACHINE\\SOFTWARE\\Flameshot\\Capabilities\\URLAssociations",
+      QSettings::NativeFormat);
+    URLAssociations.remove("ms-screenclip");
+    URLAssociations.sync();
+    if (QSettings::AccessError == URLAssociations.status()) {
+        return false;
+    }
+
+    return !isMsScreenclipRegistered();
+}
+
+#endif