Today I made a new .th2 drawing file and used a .png file as a background image.  Not something I do very much these days, as I typically use .xvi files created PocketTopo files.  The xvi images work just fine in XTherion.

But as described in the post in this link, https://www.mail-archive.com/therion@speleo.sk/msg06890.html, there are problems when using the mouse wheel to zoom if background images are .jpg or .png.  Until now I have adopted a work around of only using the menu + and – zoom buttons where th2 files are linked to these.

However for one projected elevation drawing, even the + and – controls are problematic.  I think I accidentally used the mouse wheel before inserting the image.  As a result the image is only aligned with the sketch at one particular zoom level.  144% in this case.  There is also a problem with the image clipping.

In the above example, if I zoom out one level, the drawing reduces, but the image does not change by the same amount.

If I use the zoom wheel, the situation compounds and gets worse.  So I have a situation where I can only align this drawing at one zoom level, and I have to be careful not to use the mouse wheel.

Not really a problem in this case, as it is a trivial survey and scrap, but it is a significant issue for anyone who might still be regularly using scanned sketches for drawing.

Is this something that someone knows how to address?

I’m using Therion 5.4.1+f0c98ce (2018-03-03)

Bruce