checkpoint: array visualizer.

src/QZoomChartView.cpp

@@ -0,0 +1,133 @@
+#include "QZoomChartView.h"
+#include <QtGui/QMouseEvent>
+#include <QtGui/QGuiApplication>
+#include <QtWidgets/QApplication>
+#include <QtCore/QDebug>
+
+QZoomChartView::QZoomChartView (QWidget* parent) : QChartView(parent) {
+
+    _isDragging = false;
+
+    setRubberBand(QChartView::RectangleRubberBand);
+}
+
+QZoomChartView::QZoomChartView (QChart* chart, QWidget* parent) : QChartView(chart, parent) {
+
+    _isDragging = false;
+
+    setRubberBand(QChartView::RectangleRubberBand);
+}
+
+bool QZoomChartView::viewportEvent (QEvent* event) {
+
+    return QChartView::viewportEvent(event);
+}
+
+void QZoomChartView::mousePressEvent (QMouseEvent* event) {
+
+    if (event->button() == Qt::LeftButton) {
+
+        _keyboardModifiers = QGuiApplication::keyboardModifiers();
+
+        if (_keyboardModifiers == Qt::ShiftModifier) {
+
+            QApplication::setOverrideCursor(QCursor(Qt::SizeAllCursor));
+            setRubberBand(QChartView::NoRubberBand);
+
+            _lastMousePos = event->pos();
+            _isDragging   = true;
+
+            event->accept();
+
+        }else{
+            setRubberBand(QChartView::RectangleRubberBand);
+        }
+    }
+
+    QChartView::mousePressEvent(event);
+}
+
+void QZoomChartView::mouseMoveEvent (QMouseEvent* event) {
+
+    // pan the chart with a left mouse drag
+    if (event->buttons() & Qt::LeftButton) {
+
+        if (_keyboardModifiers == Qt::ShiftModifier) {
+
+            auto dPos = event->pos() - _lastMousePos;
+
+            chart()->scroll(-dPos.x(), dPos.y());
+
+            _lastMousePos = event->pos();
+
+            event->accept();
+        }
+    }
+
+    QChartView::mouseMoveEvent(event);
+}
+
+void QZoomChartView::mouseReleaseEvent (QMouseEvent* event) {
+
+    if (_isDragging) {
+        QApplication::restoreOverrideCursor();
+        _isDragging = false;
+    }
+
+    QChartView::mouseReleaseEvent(event);
+}
+
+void QZoomChartView::wheelEvent (QWheelEvent* event) {
+
+    // https://stackoverflow.com/questions/48623595/scale-x-axis-of-qchartview-using-mouse-wheel
+
+    qreal factor = event->angleDelta().y() > 0 ? 0.5 : 2.0;
+
+    chart()->zoom(factor);
+
+    event->accept();
+
+    QChartView::wheelEvent(event);
+}
+
+void QZoomChartView::keyPressEvent (QKeyEvent* event) {
+
+    switch (event->key()) {
+        case Qt::Key_Plus:
+            chart()->zoomIn();
+            break;
+        case Qt::Key_Minus:
+            chart()->zoomOut();
+            break;
+        case Qt::Key_Escape:
+            chart()->zoomReset();
+            break;
+        case Qt::Key_Left:
+            chart()->scroll(-10, 0);
+            break;
+        case Qt::Key_Right:
+            chart()->scroll(10, 0);
+            break;
+        case Qt::Key_Up:
+            chart()->scroll(0, 10);
+            break;
+        case Qt::Key_Down:
+            chart()->scroll(0, -10);
+            break;
+        default:
+            QGraphicsView::keyPressEvent(event);
+            break;
+    }
+}
+
+void QZoomChartView::enterEvent (QEvent* event) {
+
+    Q_UNUSED(event);
+
+    setFocus();
+}
+
+void QZoomChartView::leaveEvent (QEvent* event) {
+    Q_UNUSED(event);
+}
+