1 files changed, 102 insertions, 0 deletions
diff --git a/demos/callout/callout.cpp b/demos/callout/callout.cpp
new file mode 100644
index 00000000..9f1de8cc
--- /dev/null
+++ b/demos/callout/callout.cpp
@@ -0,0 +1,102 @@
+#include "callout.h"
+#include <QPainter>
+#include <QFontMetrics>
+#include <QGraphicsSceneMouseEvent>
+#include <QMouseEvent>
+
+Callout::Callout(QGraphicsItem * parent):
+    QGraphicsItem(parent)
+{
+}
+
+QRectF Callout::boundingRect() const
+{
+    QPointF anchor = mapFromParent(m_anchor);
+    QRectF rect;
+    rect.setLeft(qMin(m_textRect.left(), anchor.x()));
+    rect.setRight(qMax(m_textRect.right() + 8, anchor.x()));
+    rect.setTop(qMin(m_textRect.top(), anchor.y()));
+    rect.setBottom(qMax(m_textRect.bottom() + 8, anchor.y()));
+    return rect;
+}
+
+void Callout::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
+{
+    Q_UNUSED(option)
+    Q_UNUSED(widget)
+    QPainterPath path;
+    path.addRoundedRect(m_textRect, 5, 5);
+
+    QPointF anchor = mapFromParent(m_anchor);
+    if (!m_textRect.contains(anchor)) {
+        QPointF point1, point2;
+
+        // establish the position of the anchor point in relation to m_textRect
+        bool above = anchor.y() <= m_textRect.top();
+        bool aboveCenter = anchor.y() > m_textRect.top() && anchor.y() <= m_textRect.center().y();
+        bool belowCenter = anchor.y() > m_textRect.center().y() && anchor.y() <= m_textRect.bottom();
+        bool below = anchor.y() > m_textRect.bottom();
+
+        bool onLeft = anchor.x() <= m_textRect.left();
+        bool leftOfCenter = anchor.x() > m_textRect.left() && anchor.x() <= m_textRect.center().x();
+        bool rightOfCenter = anchor.x() > m_textRect.center().x() && anchor.x() <= m_textRect.right();
+        bool onRight = anchor.x() > m_textRect.right();
+
+        // get the nearest m_textRect corner.
+        qreal x = (onRight + rightOfCenter) * m_textRect.width();
+        qreal y = (below + belowCenter) * m_textRect.height();
+        bool cornerCase = (above && onLeft) || (above && onRight) || (below && onLeft) || (below && onRight);
+        bool vertical = qAbs(anchor.x() - x) > qAbs(anchor.y() - y);
+
+        qreal x1 = x + leftOfCenter * 10 - rightOfCenter * 20 + cornerCase * !vertical * (onLeft * 10 - onRight * 20);
+        qreal y1 = y + aboveCenter * 10 - belowCenter * 20 + cornerCase * vertical * (above * 10 - below * 20);;
+        point1.setX(x1);
+        point1.setY(y1);
+
+        qreal x2 = x + leftOfCenter * 20 - rightOfCenter * 10 + cornerCase * !vertical * (onLeft * 20 - onRight * 10);;
+        qreal y2 = y + aboveCenter * 20 - belowCenter * 10 + cornerCase * vertical * (above * 20 - below * 10);;
+        point2.setX(x2);
+        point2.setY(y2);
+
+        path.moveTo(point1);
+        path.lineTo(mapFromParent(m_anchor));
+        path.lineTo(point2);
+        path = path.simplified();
+    }
+    painter->setBrush(QColor(255, 255, 255));
+    painter->drawPath(path);
+    painter->drawText(m_textRect.adjusted(4, 4, 0, 0), m_text);
+}
+
+void Callout::mousePressEvent(QGraphicsSceneMouseEvent *event)
+{
+    if (m_textRect.contains(event->pos())) {
+        m_clickOffset = event->pos();
+        event->setAccepted(true);
+    } else {
+        event->setAccepted(false);
+    }
+}
+
+void Callout::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
+{
+    if (m_textRect.contains(event->pos())){
+        setPos(mapToParent(event->pos() - m_clickOffset));
+        event->setAccepted(true);
+    } else {
+        event->setAccepted(false);
+    }
+}
+
+void Callout::setText(const QString &text)
+{
+    m_text = text;
+    QFontMetrics metrics(m_font);
+    prepareGeometryChange();
+    m_textRect = metrics.boundingRect(QRect(0, 0, 150, 150), Qt::AlignLeft, m_text).adjusted(0, 0, 4, 4);
+}
+
+void Callout::setAnchor(QPointF point)
+{
+    m_anchor = point;
+}