Sketcher: New flexible DSH Architecture

=======================================

Rewrite of the architecture to accomodate on-view parameters and to enable code reuse
between the default widget and custom widgets.

src/Mod/Sketcher/Gui/DrawSketchKeyboardManager.cpp

@@ -0,0 +1,129 @@
+/***************************************************************************
+ *   Copyright (c) 2023 Abdullah Tahiri <abdullah.tahiri.yo@gmail.com>     *
+ *                                                                         *
+ *   This file is part of the FreeCAD CAx development system.              *
+ *                                                                         *
+ *   This library is free software; you can redistribute it and/or         *
+ *   modify it under the terms of the GNU Library General Public           *
+ *   License as published by the Free Software Foundation; either          *
+ *   version 2 of the License, or (at your option) any later version.      *
+ *                                                                         *
+ *   This library  is distributed in the hope that it will be useful,      *
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+ *   GNU Library General Public License for more details.                  *
+ *                                                                         *
+ *   You should have received a copy of the GNU Library General Public     *
+ *   License along with this library; see the file COPYING.LIB. If not,    *
+ *   write to the Free Software Foundation, Inc., 59 Temple Place,         *
+ *   Suite 330, Boston, MA  02111-1307, USA                                *
+ *                                                                         *
+ ***************************************************************************/
+
+
+#include "PreCompiled.h"
+
+#ifndef _PreComp_
+#include <Inventor/events/SoKeyboardEvent.h>
+#include <QApplication>
+#include <QEvent>
+#include <QRegularExpression>
+#include <QRegularExpressionMatch>
+#endif
+
+#include "ViewProviderSketch.h"
+
+#include "DrawSketchKeyboardManager.h"
+
+using namespace SketcherGui;
+
+
+DrawSketchKeyboardManager::DrawSketchKeyboardManager()
+    : QObject(nullptr)
+    , keyMode(KeyboardEventHandlingMode::DSHControl)
+{
+    // get the active viewer, so that we can send it key events
+    auto doc = Gui::Application::Instance->activeDocument();
+
+    if (doc) {
+        auto temp = dynamic_cast<Gui::View3DInventor*>(doc->getActiveView());
+        if (temp) {
+            vpViewer = temp->getViewer();
+            keyMode = KeyboardEventHandlingMode::ViewProvider;
+        }
+    }
+
+    timer.setSingleShot(true);
+
+    QObject::connect(&timer, &QTimer::timeout, [this]() {
+        onTimeOut();
+    });
+}
+
+bool DrawSketchKeyboardManager::isMode(KeyboardEventHandlingMode mode)
+{
+    return mode == keyMode;
+}
+
+DrawSketchKeyboardManager::KeyboardEventHandlingMode DrawSketchKeyboardManager::getMode()
+{
+    return keyMode;
+}
+
+bool DrawSketchKeyboardManager::eventFilter(QObject* object, QEvent* event)
+{
+    Q_UNUSED(object);
+
+    if (event->type() == QEvent::KeyPress || event->type() == QEvent::KeyRelease) {
+        /*If a key shortcut is required to work on sketcher when a tool using ui controls is being
+         * used, then you have to add this key to the below section such that the spinbox doesn't
+         * keep the keypress event for itself. Note if you want the event to be handled by the
+         * spinbox too, you can return false.*/
+
+        auto keyEvent = static_cast<QKeyEvent*>(event);
+
+        detectKeyboardEventHandlingMode(keyEvent);  // determine the handler
+
+        if (vpViewer && isMode(KeyboardEventHandlingMode::ViewProvider)) {
+            return QApplication::sendEvent(vpViewer, keyEvent);
+        }
+
+        return false;  // do not intercept the event and feed it to the widget
+    }
+
+    return false;
+}
+
+void DrawSketchKeyboardManager::detectKeyboardEventHandlingMode(QKeyEvent* keyEvent)
+{
+    QRegularExpression rx(QStringLiteral("^[0-9]$"));
+    auto match = rx.match(keyEvent->text());
+    if (keyEvent->key() == Qt::Key_Enter || keyEvent->key() == Qt::Key_Return
+        || keyEvent->key() == Qt::Key_Tab || keyEvent->key() == Qt::Key_Backtab
+        || keyEvent->key() == Qt::Key_Backspace || keyEvent->key() == Qt::Key_Delete
+        || keyEvent->key() == Qt::Key_Minus || keyEvent->key() == Qt::Key_Period
+        || keyEvent->key() == Qt::Key_Comma || match.hasMatch()) {
+        keyMode = KeyboardEventHandlingMode::DSHControl;
+        timer.start(timeOutValue);
+    }
+}
+
+void DrawSketchKeyboardManager::onTimeOut()
+{
+    keyMode = KeyboardEventHandlingMode::ViewProvider;
+}
+
+/// sets the timeout to the amount of milliseconds.
+void DrawSketchKeyboardManager::setTimeOut(int milliseconds)
+{
+    timeOutValue = milliseconds;
+}
+
+// returns the current timeout amount
+int DrawSketchKeyboardManager::timeOut()
+{
+    return timeOutValue;
+}
+
+
+#include "moc_DrawSketchKeyboardManager.cpp"