Calculating visions means figuring out plans and goals for a particular issue.
John F. Kennedy, Lyndon B. Johnson, and the civil rights movement are all related to this.
John F. Kennedy was the President from 1961 to 1963, and he was the first President to take an active interest in civil rights. He issued a series of Executive Orders which desegregated public places and began the process of ending discrimination against African Americans.
Lyndon B. Johnson was the President right after Kennedy and he expanded Kennedy's vision by passing the Civil Rights Act which made discrimination against African Americans illegal. He also signed the Voting Rights Act, which gave African Americans the right to vote.
The civil rights movement was a series of protests and marches by African Americans who wanted equality and an end to discrimination. It was a very important part of achieving civil rights in the United States.
So calculating visions in this context means figuring out goals and plans to achieve true civil rights for African Americans. Kennedy and Johnson did this by issuing Executive Orders and passing laws that made it illegal to discriminate against African Americans. The civil rights movement was another way to make a difference, by highlighting the issue and showing why change was needed.