cursors: Split out mouse dragging logic into Cursor class

cursor.cpp

@@ -0,0 +1,75 @@
+/*
+ *  Copyright (C) 2016, Mike Walters <mike@flomp.net>
+ *
+ *  This file is part of inspectrum.
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <QDebug>
+#include <QMouseEvent>
+#include "cursor.h"
+
+Cursor::Cursor(QObject * parent) : QObject::QObject(parent)
+{
+
+}
+
+bool Cursor::pointOverCursor(QPoint point)
+{
+    const int margin = 5;
+    range_t<int> range = {cursorPosition - margin, cursorPosition + margin};
+    return range.contains(point.x());
+}
+
+bool Cursor::eventFilter(QObject *obj, QEvent *event)
+{
+    // Start dragging on left mouse button press, if over a cursor
+    if (event->type() == QEvent::MouseButtonPress) {
+        QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
+        if (mouseEvent->button() == Qt::LeftButton) {
+            if (pointOverCursor(mouseEvent->pos())) {
+                dragging = true;
+                return true;
+            }
+        }
+
+    // Update current cursor positon if we're dragging
+    } else if (event->type() == QEvent::MouseMove) {
+        QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
+        if (dragging) {
+            cursorPosition = mouseEvent->pos().x();
+            emit posChanged();
+        }
+
+    // Stop dragging on left mouse button release
+    } else if (event->type() == QEvent::MouseButtonRelease) {
+        QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
+        if (mouseEvent->button() == Qt::LeftButton) {
+            dragging = false;
+            return true;
+        }
+    }
+    return false;
+}
+
+int Cursor::pos()
+{
+    return cursorPosition;
+}
+
+void Cursor::setPos(int newPos)
+{
+    cursorPosition = newPos;
+}