Multiscale plot

[blelump]

Hi,

I am new on this forum and in Qt/Qwt as well.
I would like to know if is there any possibility to make a multiscale plot these days? By 'these days' I mean that I have seen this topic: http://www.qtcentre.org/forum/f-qwt-...ighlight=plots and Uwe wrote that it's not actually possible but it was 2 year's ago. So I'm asking now, can it be done? Multiscale plot has to be probably the most important feature in my project so I need to know that. Otherwise I have to write my own solution, but I'm getting headache when I'm thinking about it. Would be better to use the Qwt library.

Thank you in advance for any help.

[blelump]

I've actually found, let's say, a partial solution (the QwtPlotScaleItem class, which has been introduced in 5.1.0 version), but now I don't know how to change the colour of scale or the values. When I try methods such as setPalette or scaleDiv (which I think is for scale change) there is no effect.

[Uwe]

The scale item has its own palette, that is assigned with scaleItem->setPalette(). Backbone and ticks are painted with the foreground color, the labels are painted with the text color ( as long as YourScaleDraw::label doesn't return a text object with an individual color ).

Some time ago a user had sent me a patch that allows having 8 axes ( 2 in each direction ). I will have a look at it this weekend. If it can be ported to Qwt 5.1 I will add it to the patches section on the Qwt project page. I guess it should be possible to modify it to support more axes too.

Uwe

[blelump]

Thank you for your reply. It helped me a lot. I guess the QwtPlotScaleItem class will be enough for me for now.


Here's also a couple lines of code for those who might look for the solution:

QPalette *p = new QPalette();
p->setBrush(QPalette::Text, QBrush(Qt::red));
p->setBrush(QPalette::WindowText, QBrush(Qt::red));
QwtPlotScaleItem *scaleItem = new QwtPlotScaleItem();
scaleItem->setPalette(*p);
scaleItem->setFont(QFont (tr("blabla"), 10, 1, TRUE));
scaleItem->setScaleDivFromAxis(FALSE);
scaleItem->setScaleDiv((new QwtLinearScaleEngine())->divideScale(-28, 440, 5, 5));
scaleItem->setBorderDistance(2);
scaleItem->attach(myPlot);

QPalette *p = new QPalette();
p->setBrush(QPalette::Text, QBrush(Qt::red));
p->setBrush(QPalette::WindowText, QBrush(Qt::red));
QwtPlotScaleItem *scaleItem = new QwtPlotScaleItem();
scaleItem->setPalette(*p);
scaleItem->setFont(QFont (tr("blabla"), 10, 1, TRUE));
scaleItem->setScaleDivFromAxis(FALSE);
scaleItem->setScaleDiv((new QwtLinearScaleEngine())->divideScale(-28, 440, 5, 5));
scaleItem->setBorderDistance(2);
scaleItem->attach(myPlot);

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which generates a red scale with red labels from -28 to 440.

[blelump]

Some time ago a user had sent me a patch that allows having 8 axes ( 2 in each direction ). I will have a look at it this weekend. If it can be ported to Qwt 5.1 I will add it to the patches section on the Qwt project page. I guess it should be possible to modify it to support more axes too.

Uwe

I just would like to ask, how goes the thing with more than 2 scales per axis? I've checked the newest 5.1.1 version and I haven't seen any changes.

thanks in advance for info.

[Uwe]

The patch is available, but I don't know myself how useful it is.

Uwe

[blelump]

The patch is available, but I don't know myself how useful it is.

Uwe

Thanks for your reply, but I need some more infos.

The patch is for six new Y-axes and I reimplemented it for 10 new X-axes (because I need more X instead of Y) so there's 12 X-axes for now and it even works.
But there's a small bug cause when I try to enable some new axis, then every axis is in the same place (like on the stack). I suppose it is problem with computing new coordinates for axes. Could you tell me where I could find a method which computes coordinates for every axis or better how to fix this?