zooming when mouse hovers axis-label

[Andreas]

Hello,
I am new here and I also a newbie on programming with qwt.
Now I hope I can find help here and maybe I can help someone others.

I have a qwtPlot which works correct with zooming and panning.
My problem is, I want to zoom in an other way:
1. If my mouse is in the canvas, only the Y-axis should be zoomed.

- I think that shouldn't be a problem.

2. If my mouse is over the X-axis-label (time-label), only the X-axis should be zoomed.

- Here's my problem: How can I detect, that the mouse is hovering the X-axis-label?

Is this at all possible?
Are there any ideas for a workaround, if not?

Andreas

[Uwe]

1. If my mouse is in the canvas, only the Y-axis should be zoomed.

- I think that shouldn't be a problem.

For the panner use QwtPlotPanner::setAxisEnabled( bool ).
For the zoomer you need to have one x axis, but when you use only one of the simple assign the other one: f.e zoomer->setAxis( QwtPlot::xTop, ... );

2. If my mouse is over the X-axis-label (time-label), only the X-axis should be zoomed.

- Here's my problem: How can I detect, that the mouse is hovering the X-axis-label?

Install an event filter for the axis widget: plot->axisWidget( QwtPlot::xBottom )->installEventFilter( ... );

• plot->axisWidget( QwtPlot::xBottom )->scaleDiv() returns the values of the ticks ( labels are on the major ticks )
• plot->axisWidget( QwtPlot::xBottom )->scaleDraw()->labelRect() calculates the bounding rectangle of a labels.
• plot->axisWidget( QwtPlot::xBottom )->scaleDraw()->scaleMap() translates widget coordinates ( f.e mouse clicks ) into plot coordinates and v.v.

HTH,
Uwe

[Andreas]

Thanks a lot for fast answering Uwe.
I will try out your suggestion today or tomorrow and let you know, if this helps.

[Andreas]

Unfotunetelly I has to say, that there are some very urgent things which I has to do.
So I can't try out your proposal in the next few days.
But I thought a little bit about your post:
- When I install an eventfilter, I think I must not check where my mouse is.
I think QWT / QT handles it in the correct way.
Because I already installed an eventFilter in the canvas and it works without checking the mouse coordinates.

Is my assumption correct?

Thank you in advance