Computer Science 225
Advanced Programming

Spring 2020, Siena College

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Agenda

• Announcements
  • Problem Set 3 is due tonight, regular late policies apply
  • This week: optional exam review instead of lab meetings (first hour)
  • Exam 1: be in RB 202 at 7:00 Wednesday evening unless you've made other arrangements
• Event-driven programming
  • moving/dragging objects
• In-class exercices (10 points), work in small groups

  You will receive an invitation to create a repository that contains two of today's examples. Your tasks are to enhance them as follows:

  1. Modify the SpiralLines example so it chooses a random color for each spiral, but keep using those same colors for the entire spiral.

     Also think about these variations (but they're not required):

     • choose a new random color for every line, not every spiral
     • choose a new random color for every line every time (on each mouse event)
  2. Modify the DragABall example so the program initially draws two different colored circles at random locations within the graphics window. Then the user can drag either ball.

     Some additional considerations:

     • what if you also always want to have the circle being dragged drawn on top of the other circle?
     • what if you want to make the functionality so that when you press the mouse in a location inside both circles, you always drag the one which is drawn on top?
     • or how about if you want to drag both circles when the initial press point is on both?

  Commit and push your code when you are finished. Be sure the names of everyone who worked together is in the README.md file and in both programs.

Terminology

• event-driven program
• listeners
• event handlers
• absolute move
• translate/relative move

Examples

• SpiralLines
• SunAndMoon
• UglyDragABall
• DragABall