How do I screenshot a specifc part of the layout? (Using drawing canvas area)

I'm trying to screenshot specific part of the layout.

To do so, I'm trying to use the drawing canvas area. So, I currently set the system > take snapshot with drawing canvas axis and both the width and lenght set to 0.

Then, I use the invoke snapshot download action. The problem is that the snapshot gets almost all the layout size and not online de drawing canvas area.

Any way of fixing this?

Thanks in advance!

Thank you for these! Extremely helpful advice!

For some odd reason, the mentioned topic didn't appear when I googled it. Maybe I should use the forum search instead!