xBottom Scale Overide

[baray98]

Hi All,

How can i move scale 1 to the middle of 0 and 1?

(explaination)
I am plotting data from a sensor from each device ( say two devices in this case )

so in my plot I use xBottom scale as my device number and made sure that all sensor points (data) from device 1 will stay in 0 to 1 tick in my plot, and the data from device 2 will be ploted in 1 to 2 tick.

Now, I'd like to move the label to the middle of the block not at the edge. say number 1 the x scale should be drawn in between 0 and 1 tick.

hoping you understand what i am talking about,

baray98

[Uwe]

You want a label for the interval, not for a position ( on my TODO list since some time ). This is not possible with Qwt 5.x, but you can implement the following workaround:

With QwtPlot::setAxisScaleDiv you can assign scales with irregular tick positions. The labels are always below the major ticks.
Assign minor ticks at 0 and 1 and a major tick at 0.5. Then set the tick length for major ticks to 0 and increase the tick length for the minor ticks ( QwtScaleDraw::setTickLength() ).

HTH,
Uwe

[baray98]

Assign minor ticks at 0 and 1 and a major tick at 0.5.

Can you give a little snippets on how to do this on QwtScaleDiv. I did not really understand it

My devices are actually 128 and each devices will have a max sensor of 48. If there is a little something that i can start with QwtScaleDiv then I can figure out the rest.

baray98

[Uwe]

Its a class with the min/max values of your scale and 3 arrays with the values, where the ticks are. Nothing that could be misunderstood.

Uwe

[baray98]

Hi Uwe,

I got it running on single plot but when i tried to incorporate it to the "plot matrix" example where , x axis are sycnhronize, it did somehow went back ot its regular ticks. This only happens when i would play with the setAxisScale or change the axisScale on xBottom of the matrix.

Any hint of whats going on ? whos putting the regular ticks back?

baray98

p.s. thank you very much for your help

[frankiefrank]

I have a related question, on the same subject:

I can't seem to locate QwtScaleDraw::setTickLength() in the documentation and I also didn't understand the suggested use of this method as you described it.

Could anyone please explain what that method can be used for and how?

[bss]

how to getaxis scaling range.
i want to get the min and max range of the x-axis .How can we do that?

[d_stranz]

Don't ask a new question in an existing thread. Start a new one.

To answer your question:

double axisLeft = plot->axisScaleDiv( QwtPlot::xBottom )->lBound();
double axisRight = plot->axisScaleDiv( QwtPlot::xBottom )->hBound();

double axisLeft = plot->axisScaleDiv( QwtPlot::xBottom )->lBound();
double axisRight = plot->axisScaleDiv( QwtPlot::xBottom )->hBound();

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