Added roi resize with mouse

ResizeHelper.cpp

@@ -0,0 +1,81 @@
+#include "ResizeHelper.h"
+
+/// The set of edges intersecting a rectangle of given pen width
+QFlags<Qt::Edge> edgesAt(const QPointF & p, const QRectF & r, qreal w) {
+    QFlags<Qt::Edge> edges;
+    auto hw = w / 2.0;
+    if (QRectF(r.x()-hw, r.y()-hw, w, r.height()+w).contains(p)) edges |= Qt::LeftEdge;
+    if (QRectF(r.x()+r.width()-hw, r.y()-hw, w, r.height()+w).contains(p)) edges |= Qt::RightEdge;
+    if (QRectF(r.x()-hw, r.y()-hw, r.width()+w, w).contains(p)) edges |= Qt::TopEdge;
+    if (QRectF(r.x()-hw, r.y()+r.height()-hw, r.width()+w, w).contains(p)) edges |= Qt::BottomEdge;
+    return edges;
+}
+
+ResizeHelper::ResizeHelper(QObject *parent) {
+    setAcceptedMouseButtons(Qt::LeftButton);
+    m_pen.setColor(QColor(255, 0, 0, 128));
+    m_pen.setStyle(Qt::SolidLine);
+}
+
+QRectF ResizeHelper::boundingRect() const {
+    auto hWidth = m_pen.widthF()/2.0;
+    return m_rect.adjusted(-hWidth, -hWidth, hWidth, hWidth);
+}
+
+void ResizeHelper::selectionChanged() {
+    if (!scene()) { setVisible(false); return; }
+    auto sel = scene()->selectedItems();
+    if (sel.isEmpty() || sel.size() > 1) { setVisible(false); return; }
+    auto item = sel.at(0);
+    if (! traits.isGraphicsItemResizeable(item)) { setVisible(false); return; }
+    setParentItem(item);
+    newGeometry();
+    setVisible(true);
+}
+
+void ResizeHelper::paint(QPainter * p, const QStyleOptionGraphicsItem *, QWidget *) {
+    p->setPen(m_pen);
+    p->drawRect(m_rect);
+}
+
+void ResizeHelper::mousePressEvent(QGraphicsSceneMouseEvent * ev) {
+    m_edges = edgesAt(ev->pos(), m_rect, m_pen.widthF());
+    if (!m_edges){ /*Moving: Store click location
+        //ev->ignore(); /*Ignore if moved*/
+        clickPos = ev->pos();
+    }
+    ev->accept();
+}
+
+void ResizeHelper::mouseMoveEvent(QGraphicsSceneMouseEvent * ev) {
+    auto pos = mapToItem(parentItem(), ev->pos());
+    auto rect = traits.rectFor(parentItem());
+
+    if (m_edges & Qt::LeftEdge) rect.setLeft(pos.x());
+    if (m_edges & Qt::TopEdge) rect.setTop(pos.y());
+    if (m_edges & Qt::RightEdge) rect.setRight(pos.x());
+    if (m_edges & Qt::BottomEdge) rect.setBottom(pos.y());
+    if (!!m_edges) {
+        traits.setRectOn(parentItem(), rect);
+        newGeometry();
+    }else{ /*Moving*/
+        QPointF d = clickPos - ev->pos();
+        rect.setLeft(rect.left()-d.x());
+        rect.setTop(rect.top()-d.y());
+        rect.setRight(rect.right()-d.x());
+        rect.setBottom(rect.bottom()-d.y());
+        traits.setRectOn(parentItem(), rect);
+        newGeometry();
+        clickPos = ev->pos();
+    }
+}
+
+void ResizeHelper::newGeometry() {
+    prepareGeometryChange();
+    auto parentRect = traits.rectFor(parentItem());
+    m_rect.setTopLeft(mapFromParent(parentRect.topLeft()));
+    m_rect.setBottomRight(mapFromParent(parentRect.bottomRight()));
+    m_pen.setWidthF(std::min(m_rect.width(), m_rect.height()) * 0.1);
+    m_pen.setJoinStyle(Qt::MiterJoin);
+    emit(itemChanged(parentItem()));
+}

ResizeHelper.h

@@ -0,0 +1,35 @@
+#ifndef ResizeHelper_H
+#define ResizeHelper_H
+
+#include <QObject>
+#include <QGraphicsObject>
+#include <QPen>
+#include <QPainter>
+#include <QGraphicsScene>
+#include <QGraphicsSceneMouseEvent>
+#include <ResizeTraits.h>
+#include <QDebug>
+
+class ResizeHelper : public QGraphicsObject
+{
+    Q_OBJECT
+
+public:
+    ResizeTraits traits;
+    QRectF m_rect;
+    QPen m_pen;
+    QPointF clickPos;
+    QFlags<Qt::Edge> m_edges;
+    ResizeHelper(QObject *parent = 0);
+    QRectF boundingRect() const Q_DECL_OVERRIDE;
+    void newGeometry();
+    void paint(QPainter * p, const QStyleOptionGraphicsItem *, QWidget *);
+    void mousePressEvent(QGraphicsSceneMouseEvent * ev) Q_DECL_OVERRIDE;
+    void mouseMoveEvent(QGraphicsSceneMouseEvent * ev) Q_DECL_OVERRIDE;
+signals:
+    void itemChanged(QGraphicsItem* item);
+public slots:
+    void selectionChanged();
+};
+
+#endif // ResizeHelper_H

ResizeTraits.cpp

@@ -0,0 +1,39 @@
+#include "ResizeTraits.h"
+
+/// Determines whether an item is manually resizeable.
+bool ResizeTraits::isGraphicsItemResizeable(QGraphicsItem * item) {
+    auto resizeableItem1 = dynamic_cast<QGraphicsEllipseItem*>(item);
+    if(resizeableItem1){
+        return resizeableItem1;
+    }
+    auto resizeableItem2 = dynamic_cast<QGraphicsRectItem*>(item);
+    if(resizeableItem2){
+        return resizeableItem2;
+    }
+    return false;
+}
+
+/// Gives the rectangle one can base the resize operations on for an item
+QRectF ResizeTraits::rectFor(QGraphicsItem * item) {
+    auto resizeableItem1 = dynamic_cast<QGraphicsEllipseItem*>(item);
+    if(resizeableItem1){
+        return resizeableItem1->rect();
+    }
+    auto resizeableItem2 = dynamic_cast<QGraphicsRectItem*>(item);
+    if(resizeableItem2){
+        return resizeableItem2->rect();
+    }
+    return QRectF();
+}
+
+/// Sets a new rectangle on the item
+void ResizeTraits::setRectOn(QGraphicsItem * item, const QRectF & rect) {
+    auto resizeableItem1 = dynamic_cast<QGraphicsEllipseItem*>(item);
+    if (resizeableItem1){
+        return resizeableItem1->setRect(rect);
+    }
+    auto resizeableItem2 = dynamic_cast<QGraphicsRectItem*>(item);
+    if (resizeableItem2){
+        return resizeableItem2->setRect(rect);
+    }
+}

ResizeTraits.h

@@ -0,0 +1,15 @@
+#ifndef SIMPLETRAITS_H
+#define SIMPLETRAITS_H
+#include <QGraphicsItem>
+#include <QRectF>
+
+class SimpleTraits
+{
+public:
+    static bool isGraphicsItemResizeable(QGraphicsItem * item);
+    static QRectF rectFor(QGraphicsItem * item);
+    static void setRectOn(QGraphicsItem * item, const QRectF & rect);
+
+};
+
+#endif // SIMPLETRAITS_H