A constraint graph for a candidate routing solution is created; each node in the graph represents a position of an end of a metal shape and each arc in the graph represents a design rule constraint between two of the nodes. A solution graph is computed, for at least a portion of the constraint graph, using a shape processing algorithm. The solution graph is checked for design rule violations to generate one or more violation graphs. A constraint window and a selection of one or more arcs for at least one of the violation graphs are generated. The candidate routing solution is revised, based on one or more violated design rules corresponding to at least one of the selected arcs within the constraint window. Optionally, an integrated circuit is fabricated in accordance with the revised solution.