Implement Constraint-Based Layout in Diagrams

by Allan Gardner for haskell.org

Many diagrams are defined without knowing precise coordinates; instead, they use constraints. Currently, these constraints are solved externally and then given to diagrams. This GSOC will implement a linear constraint layout system using a pre-existing external constraint solver. I will modify diagrams-core and diagrams-library to remove any assumptions they make about numbers, so that they can be used as-is, with constraint types or with other types such as arbitrary-precision numbers.