Example of diagram plugin with some added code

Hi All
I wanted to show an example of how I use the diagram plugin with some added functions that I use in one of my research applications. I wanted to be able to upload photos and add notes, symbols and lines to them.
The added functions are: photo upload and insert; the angle is shown on lines in degrees; the object on one end of the line rotates to match the angle of the line.
Although this is a specialist application of the plugin, there are many other potential uses.
In edit view The symbols/icons can be added in different combinations to make different carts:

Here is a list showing some of the 'parts' that have been premade as svgs, to be added and scaled

Editing a photograph. I have added a library of symbols and shapes

Combining a photograph and diagram

And a diagram alone

I must add that I didn't do the extra coding myself. It is presently 'broken' but I hope to get something I can share in the near future, if anyone is interested.
I'd like to be able to work with actual dimensions, which is the next thing I want to add.
Regards
Pete
PS I couldn't find a section for the Diagram plugin, please move this to the appropriate place.