B737 Captain reported encountering wake turbulence on touchdown from a departing heavy military aircraft.

Narrative

Aircraft X was cleared to land Runway 29 at Calgary International Airport while a heavy military aircraft was cleared for takeoff ahead. The departing aircraft experienced a longer-than-anticipated takeoff roll. The landing aircraft crossed the runway threshold shortly after the departing heavy aircraft became airborne. Winds were 270 degrees with gusts up to 30 knots. The runway was physically clear prior to touchdown; however; upon landing wake turbulence was encountered. Significant rudder deflection was required by the First Officer to maintain centerline of the runway. The aircraft remained under control throughout the rollout. The event was noted unusually close compared to normal operations. Given the heavy aircraft departure; close proximity; and crosswind conditions conducive to wake drift across the runway; wake turbulence separation margins appeared minimal.