1. A method implemented in a processor-based computing system, comprising: rendering at least a portion of a diagram to a display device coupled to the computing system, the diagram comprising a plurality of elements; identifying a user gesture based on input received via at least one user input device coupled to the computing system; selecting one or more elements of the diagram based on the identified user gesture; selecting a layout constraint from among a plurality of layout constraints based on the identified user gesture, wherein each layout constraint controls a manner in which elements of a diagram are arranged when rendered to a display device; applying the selected layout constraint to the selected element(s); and rendering at least a portion of the diagram to the display device after application of the selected layout constraint to the selected element(s).