在两点之间绘制正方形

Question

I'm working on some exercises and I've been stuck on this for some hours now (quite new to Java). Anyhow, this is what I'm supposed to do: When I run the program I will have a square in the middle of the screen and when I then click somewhere within that screen another square will be drawn at the place where I clicked and in-between these two points there are supposed to be 10 squares. So wherever I click there should always be 10 squares drawn between.

However, I can't make it to function properly.

This is what I've managed to do so far:

import se.lth.cs.ptdc.window.SimpleWindow;  
import se.lth.cs.ptdc.square.Square;


public class PrintSquares2 {


public static void main(String[] args) {
    SimpleWindow w = new SimpleWindow(600, 600, "PrintSquares2");
    int posX = 300;
    int posY = 300;
    int loop = 0;
    System.out.println("Skriv rotation");
    Square sq1 = new Square(posX,posY,200);
    sq1.draw(w);


            w.waitForMouseClick();
            int destX = w.getMouseX();
            int destY = w.getMouseY();
            System.out.println("Dest X: " + destX + " Dest Y: " + destY);
            System.out.println("Pos X: " + posX + " Pos Y: " + posY);
            SimpleWindow.delay(10);
            //sq1.erase(w);
            int jumpX = (destX - posX) / 10;
            int jumpY = (destY - posY) / 10;
            System.out.println(jumpX);


                while (posX < destX)
                {       
                    posX = posX+10;
                    SimpleWindow.delay(100);
                    loop++;
                    System.out.println("Loop: " + loop);
                    System.out.println("Dest X: " + destX + " Dest Y: " + destY);
                    System.out.println("Pos X: " + posX + " Pos Y: " + posY);       
                    Square sq2 = new Square(posX,posY,200);         
                    sq2.draw(w);                        
                }

                while (posX > destX)
                {
                    posX = posX-10;
                    SimpleWindow.delay(100);
                    loop++;
                    System.out.println("Loop: " + loop);
                    System.out.println("Dest X: " + destX + " Dest Y: " + destY);
                    System.out.println("Pos X: " + posX + " Pos Y: " + posY);
                    sq1.draw(w);
                    Square sq2 = new Square(posX,posY,200);         
                    sq2.draw(w);
                }

                while (posY < destY)
                {       
                    posY = posY+10;
                    SimpleWindow.delay(100);
                    loop++;
                    System.out.println("Loop: " + loop);
                    System.out.println("Dest X: " + destX + " Dest Y: " + destY);
                    System.out.println("Pos X: " + posX + " Pos Y: " + posY);
                    sq1.draw(w);
                    Square sq2 = new Square(posX,posY,200);         
                    sq2.draw(w);
                }

                while (posY > destY)
                {
                    posY = posY-10;
                    SimpleWindow.delay(100);
                    loop++;
                    System.out.println("Loop: " + loop);
                    System.out.println("Dest X: " + destX + " Dest Y: " + destY);
                    System.out.println("Pos X: " + posX + " Pos Y: " + posY);
                    sq1.draw(w);
                    Square sq2 = new Square(posX,posY,200);         
                    sq2.draw(w);
                }


            SimpleWindow.delay(10);
            sq1.draw(w);

            //SimpleWindow.clear(w);


    }

}

I'm pretty sure that I overcomplicated everything since this should be pretty basic.

The end result is supposed to look like this: End result

Answer 1

This is the way I'd have solved it:

I didn't quite understand the documentation on se.lth.cs.ptdc.square.Square but I'll assume it draws a square given the coordinates of its top-left corner and a side size.

So you have the coodinates of your first square's left-top corner and the coordinates of the last square's center. Having that it's not difficult to get the coords of the last square's top-left corner:
lastX = centerX - side/2
lastY = centerY - side/2

After you have that you find the difference between the starting and ending points:
diffX = posX - lastX
diffY = posY - lastY

and after that just draw 9 more squares:

for (int i=1; i<10; i++){
    squareX = posX + (diffX/10)*i;
    squareY = posY + (diffY/10)*i;
    Square square = new Square(squareX,squareY,200);         
    square.draw(w);
}

Actually you did the first part right, just messed up with those unnecessary checks. Hope it helps.

--
Regards, svz.

Answer 2

Update both X and Y at the SAME time :

    int jumpX = (destX - posX) / 10;
    int jumpY = (destY - posY) / 10;
    if (posX > destX) {
        int temp = destX;
        destX = posX;
        posX = temp;
    }

    while (posX <= destX)
    {       
            SimpleWindow.delay(100);
            loop++;
            System.out.println("Loop: " + loop);
            System.out.println("Dest X: " + destX + " Dest Y: " + destY);
            System.out.println("Pos X: " + posX + " Pos Y: " + posY);       
            Square sq2 = new Square(posX,posY,200);         
            sq2.draw(w);                        
            posX = posX+jumpX;
            posY = posY+jumpY;
    }    

    SimpleWindow.delay(10);
    sq1.draw(w);

Answer 3

Here's how you move in two directions at once (on a diagonal).

static final int Steps = 10;

private void test() {
  int x1 = 100;
  int y1 = 100;
  int x2 = 300;
  int y2 = 500;

  double dx = (double)(x2 - x1) / (double) Steps;
  double dy = (double)(y2 - y1) / (double) Steps;

  double x = x1;
  double y = x2;
  for ( int i = 0; i < Steps; i++) {
    // Simulate the drawing of the square.
    System.out.println("("+x+","+y+")");
    x += dx;
    y += dy;
  }
}