Method paintCtx

src/KDChart/Cartesian/KDChartCartesianAxis.cpp:639–911

}

void CartesianAxis::paintCtx(PaintContext *context)
{
    Q_ASSERT_X(d->diagram(), "CartesianAxis::paint",
               "Function call not allowed: The axis is not assigned to any diagram.");

    auto *plane = dynamic_cast<CartesianCoordinatePlane *>(context->coordinatePlane());
    Q_ASSERT_X(plane, "CartesianAxis::paint",
               "Bad function call: PaintContext::coordinatePlane() NOT a cartesian plane.");

    // note: Not having any data model assigned is no bug
    //       but we can not draw an axis then either.
    if (!d->diagram()->model()) {
        return;
    }

    const bool centerTicks = referenceDiagramNeedsCenteredAbscissaTicks(d->diagram()) && isAbscissa();

    XySwitch geoXy(d->isVertical());

    QPainter *const painter = context->painter();

    // determine the position of the axis (also required for labels) and paint it

    qreal transversePosition = signalingNaN; // in data space
    // the next one describes an additional shift in screen space; it is unfortunately required to
    // make axis sharing work, which uses the areaGeometry() to override the position of the axis.
    qreal transverseScreenSpaceShift = signalingNaN;
    {
        // determine the unadulterated position in screen space

        DataDimension dimX = plane->gridDimensionsList().first();
        DataDimension dimY = plane->gridDimensionsList().last();
        QPointF start(dimX.start, dimY.start);
        QPointF end(dimX.end, dimY.end);
        // consider this: you can turn a diagonal line into a horizontal or vertical line on any
        // edge by changing just one of its four coordinates.
        switch (position()) {
        case CartesianAxis::Bottom:
            end.setY(dimY.start);
            break;
        case CartesianAxis::Top:
            start.setY(dimY.end);
            break;
        case CartesianAxis::Left:
            end.setX(dimX.start);
            break;
        case CartesianAxis::Right:
            start.setX(dimX.end);
            break;
        }

        transversePosition = geoXy(start.y(), start.x());

        QPointF transStart = plane->translate(start);
        QPointF transEnd = plane->translate(end);

        // an externally set areaGeometry() moves the axis position transversally; the shift is
        // nonzero only when this is a shared axis