Unit 4 Javascript Graphics Quiz Review

Where is the anchor point of a Text object located?

• 1. Top left

• 1. Top right

• 1. Center

• 1. Bottom left

• 1. Bottom right

Answer explanation

Good job! The anchor point of a Text object is located at the bottom left.

The following program should draw a circle on the screen, but when we run this code, we don’t see the circle. What is missing from our main function?

• We never set the circle’s radius.
  We need to add the line

  circle.setRadius(40);

  After line 4

• We are setting the position of the ball to be off the canvas.
  We need to change line 3 to be

  circle.setPosition(0, 0);

• We are creating the circle incorrectly. We need to specify the width and height.
  We need to change line 2 to be

  let circle = new Circle(40, 40);

• We create the circle and position it correctly on the screen, but we never add it to the screen.
  We need to add the line

  add(circle);

  after line 4

Answer explanation

Good job! In order to add an object to our canvas, we need to use the add function.

Where is the anchor point of a rectangle located?

• 1. Top left corner

• 1. Top right corner

• 1. Center

• Bottom left corner

• Bottom right corner

Consider the following code of a circle:

If we wanted to move the circle 10 pixels to the left, what change would we need to make?

• Add 10 to line 1:

  1 let circ = new Circle(60);

• Subtract 10 from the first number on line 2:

  2 circ.setPosition(190, 200);

• Subtract 10 from the second number on line 2:

  2 circ.setPosition(200, 190);

• Add 10 to the first number on line 2:

  2 circ.setPosition(210, 200);

• Add 10 to the second number on line 2:

  2 circ.setPosition(200, 210);

Answer explanation

Good job! The first value of setPosition controls the horizontal positioning of an object. Increasing the number will move an object to the right and decreasing the number will move an object to the left.

What are the x and y coordinates of the following point on the grid?

• 1. (300, 200)

• 1. (200, 300)

• 1. (200, -300)

• 1. (-300, 200)

Where is the anchor point of a circle located?

• 1. Left edge

• 1. Right edge

• 1. Center

• 1. Top edge

• 1. Bottom edge

What function do you need to call to get the width of the canvas?

• width();

• 1. getWidth();

• 1. canvasWidth();

• 1. getCanvasWidth();

True or False: All Text objects are enclosed by a rectangular box.

• True

• False