Insert after a linear curve quite demolishes the curve. The part I dont click should not be moved?
Ah ok I think maybe I haven't thoroughly explained how the visual editting works. It works based on what I'll call "key points", points that the curve will aim to pass through. When you first load it up, it will only have two key points: 0,0 and 20,100. In insert mode, every time you click somewhere it will add another key point. The app will then automatically adjust all the other non-key points so they form a straight line starting from the first keypoint (0,0), and going to the next key point. This will continue from key point to key point all the way until the last one at (20,100).
So if you start at the beginning (with only 2 keypoints) and click somewhere in the upper half (so there are now 3), the line will go straight from the lower left corner to where you clicked, then bend and go straight to the upper right corner.
In delete mode, every time you click somewhere, it will find the nearest key point and remove it. So that means where there used to be a bend before the previous key point and the next key point, all the points between those two will be smoothed into a straight line.
In move mode, every time you click somewhere, it will find the nearest key point and move it to where you clicked.
In curve mode, when you click BETWEEN two key points, it will add a curvature to the previously straight line between those points and try to calculate the curve to get as close to where you clicked as it can.
So basically, you are not supposed to click all the points to where you want them. Instead choose a couple key points outlining where you want the curve to go, and add them in insert mode. Then use curve mode to smooth out the segments in between as you like.
