qwt

Hi Ion,

> 1) I was not able to set the scale division for a logarithmical axis: I
> would like to set the start, end limits of the scale, the step and to
> revert it (or not). How can this be donewith the new API?

You should find all you had in Qwt 4x in QwtScaleEngine now. I=C2=B4m not a=
ware=20
that I have removed anything.

> 2) I want to implement scales in scientific notation (superscripts for the
> powers of 10). The way I was normally doing it with Qwt4 was by subclassi=
ng
> QwtScaleDraw and reimplementing the virtual label (double) const function.
> Now this doesn't work completely, in fact something strange happens:  the
> scales are painted correctly only if I initialize them like this in the
> QwtPlot  object. If I want the user to change them later on, this doesn't
> work, the scales remain stuck with this old format. Any hints?

Hm, maybe because of:

void QwtScaleWidget::setScaleDraw(QwtScaleDraw *sd)
{
    if ( d_data->scaleDraw )
        *sd =3D *d_data->scaleDraw;

    ...
}

Guess I had added the code above, because in the Qwt 4.x API setting a new=
=20
QwtScaleDraw killed all options that are stored in QwtScaleDraw, but it was=
=20
not obvious to the user that it was stored there. (But maybe there was=20
another reason I don't remember.)

What happens if you simply remove the 2 lines ? If there is no problem I wi=
ll=20
do the same in CVS.

Please note that I have added a plugin system for text engines. In=20
qwt/textengines/mathml you can see an example using the Qt MathML classes o=
f=20
the Qt Solutions package. It works to a certain degree, but unfortunately t=
he=20
MathML render engine is hidden from the external API and I can't publish an=
y=20
patches, because of license issues.=20

> 3) What happened with the QwtPlot::setAxisLabelFormat(int axis, ...) and
> axisLabelFormat() methods? How can I retrieve the information about the
> precision and format of the tick labels? Do I have to store this
> information by myself in my derived QwtPlot class?

The default implementation of QwtAbstractScaleDraw::label uses QString::num=
ber=20
now, without any format options. I removed the format stuff from the API,=20
simply because it doesn't match with the more powerful concept of overloadi=
ng=20
QwtAbstractScaleDraw::label. If you want to use sprintf conversions you hav=
e=20
to implement it (copy the code from Qwt 4.x) in your derived classes.

> 1) I also need to change the linewidth of the ticks and of the axes
> backbone. I achieved this by subclassing QwtScaleDraw, but I get into
> pbroblems when I want to draw the axis correctly, there are some extra
> spaces laft between the backbone and the ticks. Would it be posiible to
> incorporate this feature in Qwt?

Hm, from the code it looks like that QwtScaleDraw doesn't depend on the wid=
th=20
of the pen, but I never tried it. But all classes using a QwtScaleDraw simp=
ly=20
pass QPen(). Adding a QwtScaleWidget::setPenWidth + using a pen with this=20
width ( instead of QPen() ) might be all what is necessary.

If you need it soon please try yourself and send me the changes, if it work=
s.=20
Otherwise I will have a look at it later.=20

Uwe

Hi Ion,

> Also I have a question regarding the QwtPlotLayout: I would like to be

> able to precisely set the origin (top left corner) of the plot canvas=20
> and its size. Is it possible? If not, is there a way to achieve this?

I'm not sure if I really understand what you want to do.=20
But thats the code I use for scrolling and zooming:

  plot->setAxisScale(QwtPlot::xBottom, scaleXMin, scaleXMax, 0);
  plot->setAxisScale(QwtPlot::yLeft, scaleYMin, scaleYMax, 0);
  plot->replot();


hth,
Felix

Hi Ion,

> I've tried to build qwt5 from CVS on Windows using Qt3 and MSVC6 and I've
> got the following error message:

Fixed, thanks.

> Also I have a question regarding the QwtPlotLayout: I would like to be able
> to precisely set the origin (top left corner) of the plot canvas and its
> size. Is it possible? 

Hm,  you could try (with code from CVS): canvas()->setMinimumSize(size):

1) Size

If size is larger than what you get from the minimumSizeHints of the axes, the 
canvas should have the expected size after: 
plot->resize(plot->minimumSizeHint()); 

Maybe reimplement YourPlot::sizeHint returning QwtPlot::minimumSizeHint() and 
do a plot->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed).

2) Position

The position of the canvas depends on what is needed for painting the scales. 
Setting QwtScaleDraw::setMinimumExtend for the vertical axes will avoid the 
impact of the length of the tick labels (as long as the minimum width is 
large enough).

Uwe

Hi Uwe,

Thanks a lot for your response. The build works now on without problems on Windows.

I will test your suggestions for the canvas layout and I'll keep you posted!

Best regards,
Ion

Uwe Rathmann <Uwe.Rathmann@...> a écrit : Hi Ion,

> I've tried to build qwt5 from CVS on Windows using Qt3 and MSVC6 and I've
> got the following error message:

Fixed, thanks.

> Also I have a question regarding the QwtPlotLayout: I would like to be able
> to precisely set the origin (top left corner) of the plot canvas and its
> size. Is it possible? 

Hm,  you could try (with code from CVS): canvas()->setMinimumSize(size):

1) Size

If size is larger than what you get from the minimumSizeHints of the axes, the 
canvas should have the expected size after: 
plot->resize(plot->minimumSizeHint()); 

Maybe reimplement YourPlot::sizeHint returning QwtPlot::minimumSizeHint() and 
do a plot->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed).

2) Position

The position of the canvas depends on what is needed for painting the scales. 
Setting QwtScaleDraw::setMinimumExtend for the vertical axes will avoid the 
impact of the length of the tick labels (as long as the minimum width is 
large enough).

Uwe



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There no ready solution AFAIK.

What I want to point out there is some similarity with stacked =
histogram,
so common PlotItem will be useful to draw line from y1 to y2 for each x.
Having style=3Dline and bar markers we will get errorbar, with no =
markers and=20
controlled linewidth (and color) we easily get histogram.

Meanwhile overwriting draw() will give you ability to add extra plot =
line.

My 0.02

Regards,
Mike

-----Original Message-----
From: qwt-interest-bounces@... on behalf of Marek =
Szczypinski
Sent: Sun 6/25/2006 6:30 AM
To: qwt-interest@...
Subject: errorbar ploting - newbie question
=20
Hello,
I am kind of newbie to qwt (used it shortely and now returned back).
I want to plot curve with errorbars (I have 3 vectors - one with=20
xcoordinates, one with ycoordinates and one with error values). Is it=20
possible to do it in a simple way, (like a ready method - like an =
errorbar=20
in matlab/octave). If so, can somebody point me to some manual, or=20
usefull resources?
If there is no simple way of doing it, can somebody please give me an=20
advice on how to implement such thing?
If it is possible to do with qwt5 please le me know also.
Thanx in advance.
Marek Szczypinski

Using Tomcat but need to do more? Need to support web services, =
security?
Get stuff done quickly with pre-integrated technology to make your job =
easier
Download IBM WebSphere Application Server v.1.0.1 based on Apache =
Geronimo
http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=3D120709&bid=3D263057&dat=3D=
121642
_______________________________________________
qwt-interest mailing list
qwt-interest@...
https://lists.sourceforge.net/lists/listinfo/qwt-interest

Hi Bob,

> - Each curve has 200 points, is plot with QPen::SolidLine and is updated
> every second.

There is something very wrong. Painting 200 lines every second is absolutely 
nothing that could make a system being in trouble.

Download Qwt from CVS and start the data_plot example. It is similar to your 
application and offers a spinbox where you can increase/decrease the refresh 
rate. This should give you an indication about, what is possible on your 
system and shows you the fastest implementation.

> - Autoscale is set.

My guess is that QwtPlot::replot is called much too often (for every attribute 
change), because QwtPlot::autoReplot is enabled. You have to use it in the 
same manner as QWidget::update/setUpdatesEnabled.

If not try to find out what else is wasting the CPU time and post again. 

Uwe

Hi,

Thanks for the previous response. I have another question regarding 
background color of QwtScaleWidget. I need it to be the same as the 
QwtPlotCanvas background. I coudn't find any function call which will 
allow me to do that.by default it is the default widget background color.

Thanks
Mayank.

On Thursday 01 June 2006 23:39, Mayank M Tiwari wrote:

> I have another question regarding
> background color of QwtScaleWidget. I need it to be the same as the
> QwtPlotCanvas background. I coudn't find any function call which will
> allow me to do that.by default it is the default widget background color.

QWidget::setPalette()

Uwe

hi,

I have already tried setting QPalette for getting the background color but 
it doesn't change. What I am doing is the following :

QPalette l_palette = axisWidget->(xBottom);
l_palette->setColor(QPalette::Window,Qt::black);
axisWidget(xBottom)->setPalette(l_palette);

I have also tried directly setting the palette :
QPalette l_palette(Qt::black);
axisWidget(xBottom)->setPalette(l_palette);

Thanks
Mayank


On Thu, 1 Jun 2006, Mayank M Tiwari wrote:

> Hi,
>
> Thanks for the previous response. I have another question regarding 
> background color of QwtScaleWidget. I need it to be the same as the 
> QwtPlotCanvas background. I coudn't find any function call which will allow 
> me to do that.by default it is the default widget background color.
>
> Thanks
> Mayank.
>
>

--