Sync charts with custom scale.

[Uwe]

The space, that is needed for the tick labels, has an effect on the position of the ticks. On the left side it is possible to move parts of the label below the left scale, but as there is none on the right ...
How to solve it depends on the details of your application: f.e you could choose an alignment like in the cpuplot example, where the part of the tick labels right from the tick is smaller, than the canvas margin.

Uwe

[giker]

I figured out from Qwt sources that grid drawing depends on QwtScaleMap object. So I decided to override "canvasMap" method of QwtPlot class and pass the scale widget of another plot with visible scale.

void OneAxisDisabledPlot::setDisabledAxis(int axisId, QwtScaleWidget* baseWidget)
{
    enableAxis(axisId, false);
    m_disabledAxis = axisId;
    m_baseScaleWidget = baseWidget;
}
 
bool OneAxisDisabledPlot::isAxisDisabled(int axisId) const
{
    return m_disabledAxis == axisId;
}
 
QwtScaleMap OneAxisDisabledPlot::canvasMap(int axisId) const
{
    QwtScaleMap map;
    if(!canvas())
        return map;
 
    map.setTransformation(axisScaleEngine(axisId)->transformation());
 
    const QwtScaleDiv &sd = axisScaleDiv(axisId);
    map.setScaleInterval(sd.lowerBound(), sd.upperBound());
    const QwtScaleWidget *s = isAxisDisabled(axisId) ? m_baseScaleWidget : axisWidget(axisId);
    if(axisEnabled(axisId) || isAxisDisabled(axisId))
    {        
        if(axisId == yLeft || axisId == yRight)
        {
            double y = s->y() + s->startBorderDist() - canvas()->y();
            double h = s->height() - s->startBorderDist() - s->endBorderDist();
            map.setPaintInterval(y + h, y);
        }
        else
        {
            double x = s->x() + s->startBorderDist() - canvas()->x();
            double w = s->width() - s->startBorderDist() - s->endBorderDist();
            map.setPaintInterval(x, x + w);
        }
    }
    else
    {
        const QRect &canvasRect = canvas()->contentsRect();
        if(axisId == yLeft || axisId == yRight)
        {
            int top = 0;
            if(!plotLayout()->alignCanvasToScale(xTop))
                top = plotLayout()->canvasMargin(xTop);
 
            int bottom = 0;
            if(!plotLayout()->alignCanvasToScale(xBottom))
                bottom = plotLayout()->canvasMargin(xBottom);
 
            map.setPaintInterval(canvasRect.bottom() - bottom,
                canvasRect.top() + top);
        }
        else
        {
            int left = 0;
            if(!plotLayout()->alignCanvasToScale(yLeft))
                left = plotLayout()->canvasMargin(yLeft);
 
            int right = 0;
            if(!plotLayout()->alignCanvasToScale(yRight))
                right = plotLayout()->canvasMargin(yRight);
 
            map.setPaintInterval(canvasRect.left() + left,
                canvasRect.right() - right);
        }
    }
 
    return map;
}

void OneAxisDisabledPlot::setDisabledAxis(int axisId, QwtScaleWidget* baseWidget)
{
    enableAxis(axisId, false);
    m_disabledAxis = axisId;
    m_baseScaleWidget = baseWidget;
}

bool OneAxisDisabledPlot::isAxisDisabled(int axisId) const
{
    return m_disabledAxis == axisId;
}

QwtScaleMap OneAxisDisabledPlot::canvasMap(int axisId) const
{
    QwtScaleMap map;
    if(!canvas())
        return map;

    map.setTransformation(axisScaleEngine(axisId)->transformation());

    const QwtScaleDiv &sd = axisScaleDiv(axisId);
    map.setScaleInterval(sd.lowerBound(), sd.upperBound());
    const QwtScaleWidget *s = isAxisDisabled(axisId) ? m_baseScaleWidget : axisWidget(axisId);
    if(axisEnabled(axisId) || isAxisDisabled(axisId))
    {        
        if(axisId == yLeft || axisId == yRight)
        {
            double y = s->y() + s->startBorderDist() - canvas()->y();
            double h = s->height() - s->startBorderDist() - s->endBorderDist();
            map.setPaintInterval(y + h, y);
        }
        else
        {
            double x = s->x() + s->startBorderDist() - canvas()->x();
            double w = s->width() - s->startBorderDist() - s->endBorderDist();
            map.setPaintInterval(x, x + w);
        }
    }
    else
    {
        const QRect &canvasRect = canvas()->contentsRect();
        if(axisId == yLeft || axisId == yRight)
        {
            int top = 0;
            if(!plotLayout()->alignCanvasToScale(xTop))
                top = plotLayout()->canvasMargin(xTop);

            int bottom = 0;
            if(!plotLayout()->alignCanvasToScale(xBottom))
                bottom = plotLayout()->canvasMargin(xBottom);

            map.setPaintInterval(canvasRect.bottom() - bottom,
                canvasRect.top() + top);
        }
        else
        {
            int left = 0;
            if(!plotLayout()->alignCanvasToScale(yLeft))
                left = plotLayout()->canvasMargin(yLeft);

            int right = 0;
            if(!plotLayout()->alignCanvasToScale(yRight))
                right = plotLayout()->canvasMargin(yRight);

            map.setPaintInterval(canvasRect.left() + left,
                canvasRect.right() - right);
        }
    }

    return map;
}

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