Tree layout of layout algorithms

In the field of data visualization, it is often necessary to distribute the data according to certain rules, so that the data display is intuitive, clear and at a glance. In the engineering practice, I encountered a problem: how to make a multi-relationship with the point-edge graph according to the tree layout?

On the basis of consulting a large number of domestic and foreign materials, the author found a paper written by Bill Mill: drawing presentable trees.

Here is a brief description of the approximate idea of the algorithm: The algorithm uses a depth-first approach to traverse the entire multi-fork tree. The first step: if it is a leaf node, its x-coordinate equals the x-coordinate of its left sibling plus the spacing distance, if the non-leaf node, its x-coordinate equals the x-coordinate of its left sibling plus the spacing distance, simultaneously recording the offset (the difference between the x-coordinate and the midpoint of the child node). Step Two: Move all child nodes at the parent node's offset. The third step: calculate the contour of the multi-fork tree, if the contour value is less than 0 indicates that there is overlap between the left and right sub-tree, and offset that contour value.

Tree layout of layout algorithms