carmovie.java

java 图形处理

// main() displays a movie of
// a car driving along a road.
// (29 Sep 03)

import java.awt.*;

public class CarMovie extends Movie{

   /** Return picture of house and trees.
       Scene fits in a rectangle,
       width 40, height 30,
       bottom-left corner at (0,0).
   */
   private static Picture houseAndTrees() {
      /* Define the sun. Centre at (0,0).*/
      Picture sun =
         Picture.circle(Color.yellow).size(2);

      /* Define a tree.
         Height = 20.
         Origin at middle of base of trunk. */
      Color brown = new Color(0.2f, 0.25f, 0.1f);
      Color green = new Color(0f, 0.6f, 0.2f);
      Picture trunk =
         Picture.box(brown).scale(2,15).at(-1,0);
      Picture crown =
         Picture.circle(green).size(6).at(0,14);
      Picture tree = crown.over(trunk);

      /* Define the house.
         Height and width of house = 20.
         Bottom-left corner at (0,0). */
      Color black = Color.black;
      Color white = Color.white;
      Color red = new Color(1f, 0.2f, 0f);
      Color lightBlue = new Color(0.7f, 0.7f, 1f);
      Picture wall =
         Picture.box(white).scale(20,10)
         .under(Picture.box(black).scale(3,3).at(5,4))
         .under(Picture.box(red).scale(3,7).at(13,0));
      Picture roof =
         Picture.triangle(0,10, 10,20, 20,10, red)
         .over(Picture.box(white).scale(3,10).at(13,10));
      Picture house = roof.over(wall);

      return
         house.size(0.8).at(12,0)
         .over(tree.at(4.5,0))
         .over(tree.size(0.7).at(31,0))
         .over(tree.size(0.85).at(36,0))
         .over(sun.at(11,24));
   }

   /****************************************************/

   /** Return picture of car.
       Length of car = 100.
       Origin at bottom-left corner.
   */
   private static Picture car() {
      Color c = Color.yellow;  // Colour of car body.
      Picture body =
         Picture.box(c).scale(100,10)
         .over(Picture.triangle(0,10, 10,10, 10,20, c))
         .over(Picture.triangle(70,10, 100,10, 70,20, c))
         .over(Picture.box(c).scale(60,10).at(10,10))
         .over(Picture.box(c).scale(2,20).turn(30).at(70,16));

      Picture wheel =
         Picture.circle(Color.lightGray).size(5)
         .over(Picture.circle(Color.darkGray).size(8));

      Picture driver =
         Picture.circle(Color.pink).size(7).at(50,27)
         .under(Picture.circle(Color.white).size(7).at(50,16));

      return
         body
         .over(driver)
         .at(0,4)
         .under(wheel.at(20,7))
         .under(wheel.at(85,7));
   }     

   /****************************************************/   

   public Picture scene(double t) {
      double speed = 1.0;
         // = speed of car in picture units per movie time unit.

      /* Adjust size of car to fit scene. */
      Picture car = car().size(0.15);

      return
         car.at(-30+speed*t, 0)
         .over(houseAndTrees());
   }

   /****************************************************/

   public static void main(String[] a) {
      Movie m = new CarMovie();
      m.setAntialiasingOn(false);
      m.setFrameRate(30);
      m.show(0,0,40,30,7,Color.blue);
   }
}