ij-macro-programming-workshop
Exercise 09.02 - while-loop
Aim:
- understand the while-loop
The while loop below will draw the trace of a randomly moving agent (a random walk) onto the image. Provide the condition for the while-loop, so that the random-walk stops when it reaches the border of the image
newImage("random-walk", "8-bit", 800, 800, 1); // Create a new image of size 800x800 pixel
x = 400; // Set the starting point to 400, 400
y = 400;
makeOval(x,y,20,20); // Draw a circle around the starting point
moveTo(x,y); // Set the current drawing position to the starting point
Roi.setFillColor("green"); // Fill the circle with the color green
Your code starts after this line
while(x>=0 && x<800 && y>=0 && y<800) { // while the random walk is within the image
Your code ends before this line
x = x + 10 * round((2 * random) -1); // increment or decrement x randomly by 10
y = y + 10 * round((2 * random) -1); // increment or decrement y randomly by 10
Roi.move(x, y); // Move the circle to the new position
lineTo(x,y); // draw a line from the current drawing position to the new position
wait(10); // wait 10 milliseconds so that we can see the circle move
}
The code below is for automatically checking the result. Please ignore it!
ok = (x<1 || x>=799 || y<1 || y>=799);
if (ok)
showMessage("That's right. Great, you did it!");
else
showMessage("Your result is wrong! Please check your macro and try again!");