QwtPlot stretching

[jmsbc]

Hi,

I have a simple problem... I'm adding a QwtPlot to a QMainWindow's central widget. I was wondering how to keep the QwtPlot as a square (maintaining aspect ratio) instead of stretching whenever the mainWindow stretches?

Thank you

[Uwe]

Try QwtPlotRescaler from Qwt 5.2.

Uwe

[huseyinkozan]

Try QwtPlotRescaler from Qwt 5.2.

Uwe

And navigation example in the svn to learn how to use:
http://qwt.svn.sourceforge.net/viewv...34&view=markup


Hüseyin

[jmsbc]

Thanks for both of your help!

[hml]

I have tried with this code:

QApplication& appref = app;  
  QWidget window;   
  window.setWindowTitle("...");
 
  QwtPlot dataPlot(QwtText("..."), &window);
  dataPlot.setAxisTitle( QwtPlot::xBottom, "time" );
  dataPlot.setAxisTitle( QwtPlot::yLeft, "data" );
 
  QwtPlotRescaler dataPlotRescaler(dataPlot.canvas());
  dataPlotRescaler.setReferenceAxis(QwtPlot::xBottom);
  dataPlotRescaler.setAspectRatio(QwtPlot::yLeft, 1.0);
  dataPlotRescaler.setAspectRatio(QwtPlot::yRight, 0.0);
  dataPlotRescaler.setAspectRatio(QwtPlot::xTop, 0.0);
 
  window.connect(&dataPlot, SIGNAL(resized(double, double)), SLOT(showRatio(double, double)));
 
  QwtPlotCurve pc;
  Data data(d);
  pc.setData(data);      
  pc.attach(&dataPlot);
  dataPlot.replot();
  window.show();
  appref.exec();

QApplication& appref = app;  
  QWidget window;   
  window.setWindowTitle("...");

  QwtPlot dataPlot(QwtText("..."), &window);
  dataPlot.setAxisTitle( QwtPlot::xBottom, "time" );
  dataPlot.setAxisTitle( QwtPlot::yLeft, "data" );

  QwtPlotRescaler dataPlotRescaler(dataPlot.canvas());
  dataPlotRescaler.setReferenceAxis(QwtPlot::xBottom);
  dataPlotRescaler.setAspectRatio(QwtPlot::yLeft, 1.0);
  dataPlotRescaler.setAspectRatio(QwtPlot::yRight, 0.0);
  dataPlotRescaler.setAspectRatio(QwtPlot::xTop, 0.0);

  window.connect(&dataPlot, SIGNAL(resized(double, double)), SLOT(showRatio(double, double)));

  QwtPlotCurve pc;
  Data data(d);
  pc.setData(data);      
  pc.attach(&dataPlot);
  dataPlot.replot();
  window.show();
  appref.exec();

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This is taken from
http://qwt.svn.sourceforge.net/viewv...34&view=markup

which doesn't seem to exist in the examples in https://qwt.svn.sourceforge.net/svnr...anches/qwt-5.2

The window that comes out is big, but the plot is small, in the top left corner.
I wished to bind the plot to the whole window and resize the plot when I resize the window first. And then maybe change the scale of the axes when the plot is resized.

rds,

[Uwe]

You need to add a layout for your window, where you add the plot widget ( or overload resizeEvent of widget and resize the plot manually ). But this is basic Qt and has not much to do with Qwt.

The rescaler is responsible for adjusting the scales, when the plot is resized, but it doesn't resize the plot.

Uwe

[hml]

That is what i was suspecting. I am new to Qt as well.
Thanks very much for your answer,

[mqt]

Hi,
I am trying the same thing. I have inherited a class from QWTPlot and inside that I am calling

QwtPlotRescaler rescaler(canvas());
rescaler.setReferenceAxis(QwtPlot::xBottom);
rescaler.setAspectRatio(QwtPlot::yLeft, 1.0);

QwtPlotRescaler rescaler(canvas());
rescaler.setReferenceAxis(QwtPlot::xBottom);
rescaler.setAspectRatio(QwtPlot::yLeft, 1.0);

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Initially my plot X,Y axes have same range,0 to 1. But My data changes such that y axis range is -1 to 1 keeping x axis range 0 to 1, my aspect ratio is changed. I expected that the plot will become a rectangle of height=2*width. But it remains as a square and Y axis got shrunk. I need to dynamically change the Y axis range and need to maintain aspect ratio. What I need to do?