how to make the plot display the last curve drawn ??

[jesse_mark]

Hello guys,

How can i make the plot display the last curve i draw ??
for example, i draw curve 1 then i draw curve two in coodinate that far a way of curve one ... now i need to zoom and look for curve2 >>>

how can i make the plot show the last curve with out me looking for it.
and is there away where i can click on the legend and make it move to the clicked curve ??

Thanks

[Uwe]

Use autoscaling ( read about QwtPlot::setAxisAutoScale() ). All else you need to do is to set/unset the QwtPlotItem::AutoScale flags of your curves depending on your current context before calling replot.

Uwe

[jesse_mark]

I think i still doing something wrong,

I tried doing :

setAxisAutoScale(QwtPlot::xBottom);
 
     setAxisAutoScale(QwtPlot::yLeft);
 
  // before I call replot(), i set 
 
 myCurve->setItemAttribute(QwtPlotItem::AutoScale,true);

setAxisAutoScale(QwtPlot::xBottom);

     setAxisAutoScale(QwtPlot::yLeft);

  // before I call replot(), i set 

 myCurve->setItemAttribute(QwtPlotItem::AutoScale,true);

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but still i have to look for the curve on the plot, could you please tell me what is the the wrong thing im doing ?

Thanks

[Uwe]

myCurve1->setItemAttribute( QwtPlotItem::AutoScale, false );
myCurve2->setItemAttribute( QwtPlotItem::AutoScale, true );
plot->setAxisAutoScale(QwtPlot::xBottom);
plot->setAxisAutoScale(QwtPlot::yLeft);
plot->replot();

myCurve1->setItemAttribute( QwtPlotItem::AutoScale, false );
myCurve2->setItemAttribute( QwtPlotItem::AutoScale, true );
plot->setAxisAutoScale(QwtPlot::xBottom);
plot->setAxisAutoScale(QwtPlot::yLeft);
plot->replot();

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or

QRectF br = myCurve2->boundingRect();
plot->setAxisAutoScale(QwtPlot::xBottom, br.left(), br.right() );
plot->setAxisAutoScale(QwtPlot::yLeft, br.top(), br.bottom() );

QRectF br = myCurve2->boundingRect();
plot->setAxisAutoScale(QwtPlot::xBottom, br.left(), br.right() );
plot->setAxisAutoScale(QwtPlot::yLeft, br.top(), br.bottom() );

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Uwe

[jesse_mark]

thanks Uwe,

this exactlly what i need... but the second way when i use the boundingRect for the curve,

The method

plot->setAxisAutoScale(QwtPlot::xBottom, br.left(), br.right() );

plot->setAxisAutoScale(QwtPlot::xBottom, br.left(), br.right() );

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is not exist.

Is it in a new version of qwt ?

[Uwe]

No, of course it is: QwtPlot::setAxisScale.

Uwe

[jesse_mark]

using the Auto Scale works great, but there is affects other scales.

Let me elaborate it.

I am using

rescaler = new QwtPlotRescaler( myplot->canvas() );
    rescaler->setReferenceAxis( QwtPlot::xBottom );
    rescaler->setAspectRatio( QwtPlot::yLeft, 1.0 );
    rescaler->setAspectRatio( QwtPlot::yRight, 0.0 );
    rescaler->setAspectRatio( QwtPlot::xTop, 0.0 );
    rescaler->setAspectRatio( QwtPlot::xBottom, 1.0 );
    rescaler->setRescalePolicy( QwtPlotRescaler::Fixed );

rescaler = new QwtPlotRescaler( myplot->canvas() );
    rescaler->setReferenceAxis( QwtPlot::xBottom );
    rescaler->setAspectRatio( QwtPlot::yLeft, 1.0 );
    rescaler->setAspectRatio( QwtPlot::yRight, 0.0 );
    rescaler->setAspectRatio( QwtPlot::xTop, 0.0 );
    rescaler->setAspectRatio( QwtPlot::xBottom, 1.0 );
    rescaler->setRescalePolicy( QwtPlotRescaler::Fixed );

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this code to prevent the curve to be stretched and lose its real shape.
but when i use the AutoScale before i replot, the curve get stretched , where i have to zoom in and out so the rescaler works and the curve gets its "unstreached shape".

how can i fix this issue.

Thanks