Sorry I don't have a spare latch to take apart. Tried to do the next best thing. A photo to scale, so you should be able to trace.
The photo is correct if you measure the latch extension (yellow line) and the extension is 30 cm wide. The green line curve is 3/4" dia and the purple line curve is 2-1/8" dia. The end under the latch extension ends just short of the pin's inner diameter (about a 1/16" less than the width of the slot on the latch extension. It becomes a tighter curve on top as it goes under the latch extension. It looks like a 3/4" radius. (It has to clear the pin so I measured from the center point the piece pivots from. The top curve of the cam (under the latch extension) comes to a dull point. The bottom has a short flat spot on the end where it comes in contact with the folded end of the latch extension.
Hope this gets you closer. I used Paint to get the scale correct by resizing till it matched.