Re: QwtScaleWidget has wrong scale

Hi Klaus,
> 
> I tried to use a QwtScaleWidget stand-alone for a colour bar scale which I 
> want to use independently from QwtPlot. I looked into the spectrogram example 
> and the Qwt source code and finally tried the following:
> 
>... 
> Surprisingly, the scale does not start at the end of the colour bar, but has 
> some offset, thus the numbers do not correctly correspond to the colours 
> (which is, however, correct in the spectrogram example, where a QwtPlot axis 
> is used); see attached screen shot of my test application. What have I done 
> wrong?

I guess the problem is that the scale reserves some space for the 
numbers which would otherwise go out of the frame on top and at the 
bottom. I had the same problem with a Thermo. You can ask for that 
space. I did it like this: Derived my own version of a Thermo (or 
colourbar in your case) and added a method scaleMargin as follows

	int scaleMargin() const
	{
		int y1,y2;
		scaleDraw()->getBorderDistHint(font(), y1, y2);
		int y = qMax(y1,y2);
		return y;
	}

Then,

         thermoLayout = new QVBoxLayout();
	int margin=thermoLevel->scaleMargin();
         thermoLevel->setMinimumSize(QSize(48, 170-2*margin));
	thermoLayout->setContentsMargins(0, margin, 0, margin);
	thermoLayout->addWidget(thermoLevel);
	gridLayout->addLayout(thermoLayout, 1, 1, 1, 1);

Thus, you shrink the colour-bar to fit the scale.

Hope that helps,

Rainer

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