C++ QPolygon::isEmpty方法代码示例

//将位置转换成字符串
QwtText RectPicker::trackerTextF(const QPointF &pos) const
{
	QwtText text;

	const QPolygon points = selection();//选择的点
	if (!points.isEmpty())
	{
		QString num;
		QPoint point = points[0];
		QPointF point2 = invTransform(point);
		num = QString("(%1,%2),(,)").arg(point2.x()).arg(point2.y());
		QColor bg(Qt::white);
		bg.setAlpha(200);
		if (points.size() == 2)
		{

			QPointF point0 = invTransform(points[0]);
			QPointF point1 = invTransform(points[1]);
			num = QString("(%1,%2),(%3,%4)").arg(point0.x()).arg(point0.y()).arg(point1.x()).arg(point1.y());
		}
		text.setBackgroundBrush(QBrush(bg));
		text.setText(num);
	}
	return text;
}

void FreeRegionGrabber::grabRect()
{
    QPolygon pol = selection;
    if ( !pol.isEmpty() )
    {
	grabbing = true;

        int xOffset = pixmap.rect().x() - pol.boundingRect().x();
        int yOffset = pixmap.rect().y() - pol.boundingRect().y();
        QPolygon translatedPol = pol.translated(xOffset, yOffset);

        QPixmap pixmap2(pol.boundingRect().size());
        pixmap2.fill(Qt::transparent);

        QPainter pt;
        pt.begin(&pixmap2);
        if (pt.paintEngine()->hasFeature(QPaintEngine::PorterDuff)) {
            pt.setRenderHints(QPainter::Antialiasing | QPainter::HighQualityAntialiasing | QPainter::SmoothPixmapTransform, true);
            pt.setBrush(Qt::black);
            pt.setPen(QPen(QBrush(Qt::black), 0.5));
            pt.drawPolygon(translatedPol);
            pt.setCompositionMode(QPainter::CompositionMode_SourceIn);
        } else {
            pt.setClipRegion(QRegion(translatedPol));
            pt.setCompositionMode(QPainter::CompositionMode_Source);
        }

        pt.drawPixmap(pixmap2.rect(), pixmap, pol.boundingRect());
        pt.end();

        emit freeRegionUpdated(pol);
        emit freeRegionGrabbed(pixmap2);
    }
}

static void qDrawWinArrow(QPainter *p, Qt::ArrowType type, bool down,
                           int x, int y, int w, int h,
                           const QPalette &pal, bool enabled)
{
    QPolygon a;                                // arrow polygon
    switch (type) {
    case Qt::UpArrow:
        a.setPoints(7, -3,1, 3,1, -2,0, 2,0, -1,-1, 1,-1, 0,-2);
        break;
    case Qt::DownArrow:
        a.setPoints(7, -3,-1, 3,-1, -2,0, 2,0, -1,1, 1,1, 0,2);
        break;
    case Qt::LeftArrow:
        a.setPoints(7, 1,-3, 1,3, 0,-2, 0,2, -1,-1, -1,1, -2,0);
        break;
    case Qt::RightArrow:
        a.setPoints(7, -1,-3, -1,3, 0,-2, 0,2, 1,-1, 1,1, 2,0);
        break;
    default:
        break;
    }
    if (a.isEmpty())
        return;

    if (down) {
        x++;
        y++;
    }

    QPen savePen = p->pen();                        // save current pen
    if (down)
        p->setBrushOrigin(p->brushOrigin() + QPoint(1,1));
    p->fillRect(x, y, w, h, pal.brush(QPalette::Button));
    if (down)
        p->setBrushOrigin(p->brushOrigin() - QPoint(1,1));
    if (enabled) {
        a.translate(x+w/2, y+h/2);
        p->setPen(pal.foreground().color());
        p->drawLine(a.at(0), a.at(1));
        p->drawLine(a.at(2), a.at(2));
        p->drawPoint(a[6]);
    } else {
        a.translate(x+w/2+1, y+h/2+1);
        p->setPen(pal.light().color());
        p->drawLine(a.at(0), a.at(1));
        p->drawLine(a.at(2), a.at(2));
        p->drawPoint(a[6]);
        a.translate(-1, -1);
        p->setPen(pal.mid().color());
        p->drawLine(a.at(0), a.at(1));
        p->drawLine(a.at(2), a.at(2));
        p->drawPoint(a[6]);
    }
    p->setPen(savePen);                        // restore pen
}

    virtual QwtText trackerTextF( const QPointF &pos ) const
    {
        QwtText text;

        const QPolygon points = selection();
        if ( !points.isEmpty() )
        {
            QString num;
            num.setNum( QLineF( pos, invTransform( points[0] ) ).length() );

            QColor bg( Qt::green );
            bg.setAlpha( 200 );

            text.setBackgroundBrush( QBrush( bg ) );
            text.setText( num );
        }
        return text;
    }

void NodeElement::updateData()
{
	Element::updateData();
	if (!mMoving) {
		QPointF newpos = mGraphicalAssistApi.position(id());
		QPolygon newpoly = mGraphicalAssistApi.configuration(id());

		QRectF newRect; // Use default ((0,0)-(0,0))
		// QPolygon::boundingRect is buggy :-(
		if (!newpoly.isEmpty()) {
			int minx = newpoly[0].x();
			int miny = newpoly[0].y();
			int maxx = newpoly[0].x();
			int maxy = newpoly[0].y();
			for (int i = 1; i < newpoly.size(); ++i) {
				if (minx > newpoly[i].x()) {
					minx = newpoly[i].x();
				}
				if (maxx < newpoly[i].x()) {
					maxx = newpoly[i].x();
				}
				if (miny > newpoly[i].y()) {
					miny = newpoly[i].y();
				}
				if (maxy < newpoly[i].y()) {
					maxy = newpoly[i].y();
				}
			}
			newRect = QRectF(QPoint(minx, miny), QSize(maxx - minx, maxy - miny));
		}

		setGeometry(newRect.translated(newpos));
	}
	mElementImpl->updateData(this);
	updateLabels();
	update();
}

bool SeamCarver::iteration()
{
    QList<QPolygon *> listLignes;
    QPoint item;
    int strengthValue;
    QList<int> listStrengthValue;
    QList<int> listOrderedStrengthValue;
    QPolygon *polyg;
    bool route_bloquee;

    for(int h=0;h<imgOrigine->height();h++){
        route_bloquee=false;
        if (b_Pos_interdit[h][0] == false)
        {
            polyg = new QPolygon();
            item = QPoint(0,h);
            *polyg << item;
            strengthValue = getPointEnergy(h,0);
            for (int w=1; w<(imgOrigine->width()-1); w++) {
                item = leastRouteNextPointAt(item,strengthValue);
                if (item.y() < 0) //Cas 3 routes bloquées
                {
                    w=imgOrigine->width();
                    route_bloquee=true;

                } else
                    *polyg << item;
            }
            if (route_bloquee==false)
            {
                *polyg << QPoint(imgOrigine->width()-1,item.y());
                listStrengthValue << strengthValue;
                listOrderedStrengthValue << strengthValue;
                listLignes <<polyg;
            } else
                delete polyg;
        }
    }
    if (listOrderedStrengthValue.isEmpty())
        return false;
    qSort(listOrderedStrengthValue);
    int strLeast;
    int index=1;
    polyg = NULL;
    strLeast = listOrderedStrengthValue.takeFirst();
    index = listStrengthValue.indexOf(strLeast);
    listStrengthValue.takeAt(index);
    polyg = listLignes.takeAt(index);
    listLignesMostSuitable << polyg;
    if ((polyg != NULL) && (!polyg->isEmpty()))
    {
        QVectorIterator<QPoint> qit(*polyg);
        while (qit.hasNext())
        {
            item=qit.next();
            b_Pos_interdit[item.y()][item.x()]= true;
        }
    }
    qDeleteAll(listLignes);
    return true;
}