qgraphicspathitem how to get the outline

[tf520]

2014-09-25 17_44_56 _______________.png 1.png 1.png

the color of semicircle changed when my mouse hover in half round area. But I want the color changed when my mouse right on the circle（outline） , not half round area.How to write the code?

[tf520]

My Code like this, how to edit it ?

#include "item.h"
 
Item::Item()
{
    hover = false;
    setAcceptHoverEvents(true);
}
 
QRectF Item::boundingRect() const
{
    qreal extra = (pen().width() + 20) / 2.0;
    return QRectF(path().boundingRect()).normalized().adjusted(-extra, -extra, extra, extra);
}
 
QPainterPath Item::shape() const
{
       QPainterPath path;
       QRectF rect(0, 0, 100, 100);
       path.arcMoveTo(rect, 0);
       path.arcTo(rect, 0, 180);
       return path;
}
 
void Item::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
 
    QPen mypen = pen();
    QBrush mybrush;
    mybrush.setStyle(Qt::NoBrush);
    mypen.setWidth(2);
    if(hover)
    {
        mypen.setColor(Qt::red);
    }
    else
    {
        mypen.setColor(Qt::black);
    }
    painter->setRenderHint(QPainter::Antialiasing,true);
    painter->setPen(mypen);
    painter->setBrush(mybrush);
    QPainterPath path;
 
    QRectF rect(0, 0, 100, 100);
    path.arcMoveTo(rect, 0);
    path.arcTo(rect, 0, 180);
 
    setPath(path);
    painter->drawPath(path);
}
 
void Item::hoverEnterEvent(QGraphicsSceneHoverEvent *)
{
    hover = true;
    update();
}
 
void Item::hoverLeaveEvent(QGraphicsSceneHoverEvent *)
{
    hover = false;
    update();
}

#include "item.h"

Item::Item()
{
    hover = false;
    setAcceptHoverEvents(true);
}

QRectF Item::boundingRect() const
{
    qreal extra = (pen().width() + 20) / 2.0;
    return QRectF(path().boundingRect()).normalized().adjusted(-extra, -extra, extra, extra);
}

QPainterPath Item::shape() const
{
       QPainterPath path;
       QRectF rect(0, 0, 100, 100);
       path.arcMoveTo(rect, 0);
       path.arcTo(rect, 0, 180);
       return path;
}

void Item::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{

    QPen mypen = pen();
    QBrush mybrush;
    mybrush.setStyle(Qt::NoBrush);
    mypen.setWidth(2);
    if(hover)
    {
        mypen.setColor(Qt::red);
    }
    else
    {
        mypen.setColor(Qt::black);
    }
    painter->setRenderHint(QPainter::Antialiasing,true);
    painter->setPen(mypen);
    painter->setBrush(mybrush);
    QPainterPath path;

    QRectF rect(0, 0, 100, 100);
    path.arcMoveTo(rect, 0);
    path.arcTo(rect, 0, 180);

    setPath(path);
    painter->drawPath(path);
}

void Item::hoverEnterEvent(QGraphicsSceneHoverEvent *)
{
    hover = true;
    update();
}

void Item::hoverLeaveEvent(QGraphicsSceneHoverEvent *)
{
    hover = false;
    update();
}

To copy to clipboard, switch view to plain text mode 

[wysota]

shape() is used for detecting collisions. So it is a matter of getting shape() implemented correctly. On the other hand hover events probably use the bounding rect, so you should check for shape collision in your hover events.