qwt log scale Y and linear scale X

[Annihilator]

Hello. How can I do the next:
http://screencast.com/t/C47TserwI
I understand that I need to use QwtLog10ScaleEngine but how?

Thanks!

[Uwe]

The plot on the screenshot is not logarithmic base 10 - so QwtLog10ScaleEngine won't help.

You need to use Qwt 6.1 ( from SVN trunk or wait until end of this week ). Here you can add your own type of transformation ( QwtTransform ) - but of course you need to understand the transformation used in the screenshot first. For me it looks more like QwtPowerTransform than QwtLogTransform. ( the playground/scaleengine you find an application that plays with transformations - click on the legend to see the effect )

Another problem is that the axis values are not unique - each value can be found in the upper and in the lower half. But as you know where to put a curve point there seems to be another hidden coordinate system for the y values behind.

So these are the steps you need to start with:


Identify the real coordinate system and how to map coordinates into the systems on the y axes
Find the transformation used for each axis



Uwe