File indexing completed on 2024-04-28 15:51:42

 /*
     SPDX-FileCopyrightText: 2020 David Hurka <david.hurka@mailbox.org>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #include "cursorwraphelper.h"
 
 #include <QCursor>
 #include <QGuiApplication>
 #include <QRect>
 #include <QScreen>
 
 QPointer<QScreen> CursorWrapHelper::s_lastScreen;
 QPoint CursorWrapHelper::s_lastCursorPosition;
 QPoint CursorWrapHelper::s_lastWrapOperation;
 
 QPoint CursorWrapHelper::wrapCursor(QPoint eventPosition, Qt::Edges edges)
 {
     QScreen *screen = getScreen();
     if (!screen) {
         return QPoint();
     }
 
     // Step 1: Generate wrap operations.
     // Assuming screen->geometry() is larger than 10x10.
     const QRect screenGeometry = screen->geometry();
     const QPoint screenCursorPos = QCursor::pos(screen);
 
     if (edges & Qt::LeftEdge && screenCursorPos.x() < screenGeometry.left() + 4) {
         QCursor::setPos(screen, screenCursorPos + QPoint(screenGeometry.width() - 10, 0));
         s_lastWrapOperation.setX(screenGeometry.width() - 10);
     } else if (edges & Qt::RightEdge && screenCursorPos.x() > screenGeometry.right() - 4) {
         QCursor::setPos(screen, screenCursorPos + QPoint(-screenGeometry.width() + 10, 0));
         s_lastWrapOperation.setX(-screenGeometry.width() + 10);
     }
 
     if (edges & Qt::TopEdge && screenCursorPos.y() < screenGeometry.top() + 4) {
         QCursor::setPos(screen, screenCursorPos + QPoint(0, screenGeometry.height() - 10));
         s_lastWrapOperation.setY(screenGeometry.height() - 10);
     } else if (edges & Qt::BottomEdge && screenCursorPos.y() > screenGeometry.bottom() - 4) {
         QCursor::setPos(screen, screenCursorPos + QPoint(0, -screenGeometry.height() + 10));
         s_lastWrapOperation.setY(-screenGeometry.height() + 10);
     }
 
     // Step 2: Catch wrap movements.
     // We observe the cursor movement since the last call of wrapCursor().
     // If the cursor moves in the same magnitude as the last wrap operation,
     // we return the value of this wrap operation with appropriate sign.
     const QPoint cursorMovement = eventPosition - s_lastCursorPosition;
     s_lastCursorPosition = eventPosition;
 
     QPoint ret_wrapDistance;
 
     qreal horizontalMagnitude = qAbs(qreal(s_lastWrapOperation.x()) / qreal(cursorMovement.x()));
     int horizontalSign = cursorMovement.x() > 0 ? 1 : -1;
     if (0.5 < horizontalMagnitude && horizontalMagnitude < 2.0) {
         ret_wrapDistance.setX(qAbs(s_lastWrapOperation.x()) * horizontalSign);
     }
 
     qreal verticalMagnitude = qAbs(qreal(s_lastWrapOperation.y()) / qreal(cursorMovement.y()));
     int verticalSign = cursorMovement.y() > 0 ? 1 : -1;
     if (0.5 < verticalMagnitude && verticalMagnitude < 2.0) {
         ret_wrapDistance.setY(qAbs(s_lastWrapOperation.y()) * verticalSign);
     }
 
     return ret_wrapDistance;
 }
 
 void CursorWrapHelper::startDrag()
 {
     s_lastWrapOperation.setX(0);
     s_lastWrapOperation.setY(0);
 }
 
 QScreen *CursorWrapHelper::getScreen()
 {
     const QPoint cursorPos = QCursor::pos();
 
     if (s_lastScreen && s_lastScreen->geometry().contains(cursorPos)) {
         return s_lastScreen;
     }
 
     const QList<QScreen *> screens = QGuiApplication::screens();
     for (QScreen *screen : screens) {
         if (screen->geometry().contains(cursorPos)) {
             s_lastScreen = screen;
             return screen;
         }
     }
     // Corner case: cursor already pushed against an edge.
     for (QScreen *screen : screens) {
         if (screen->geometry().adjusted(-5, -5, 5, 5).contains(cursorPos)) {
             s_lastScreen = screen;
             return screen;
         }
     }
 
     return nullptr;
 }