Abstract: Features are provided for graphically representing constraints on design objects in an Electronic Design Automation tool. A particular constraint on one or more circuit objects is displayed as a highlighted region that extends to each visible circuit object to which the constraint applies. Attributes of the highlighted region, such as density and thickness, may proportionally represent attributes of the constraint, such as a strength or distance specified by the constraint. The highlighted region is superimposed on or around circuit objects. The highlighted region may be a halo, which is a partially transparent region filled with a color. Multiple regions that represent the same type of constraint or relationship are connected by line segments, providing the ability to visualize groups of constrained objects, including groups that span levels of a hierarchical design. Intersecting highlighted regions are blended together using techniques such as alpha blending.

Abstract: A computer aided design tool and method for designing IC layouts by recommending subcircuit layout constraints based upon an automated identification from a circuit schematic of subcircuit types requiring special IC layout constraints. Subcircuit types are identified on the basis of netlist examination, as well as cues from the layout of the circuit schematic.