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// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/09/Square/Square.jack
/** Implements a graphical square. */
class Square {
field int x, y; // screen location of the square's top-left corner
field int size; // length of this square, in pixels
/** Constructs a new square with a given location and size. */
constructor Square new(int Ax, int Ay, int Asize) {
let x = Ax;
let y = Ay;
let size = Asize;
do draw();
return this;
}
/** Disposes this square. */
method void dispose() {
do Memory.deAlloc(this);
return;
}
/** Draws the square on the screen. */
method void draw() {
do Screen.setColor(true);
do Screen.drawRectangle(x, y, x + size, y + size);
return;
}
/** Erases the square from the screen. */
method void erase() {
do Screen.setColor(false);
do Screen.drawRectangle(x, y, x + size, y + size);
return;
}
/** Increments the square size by 2 pixels. */
method void incSize() {
if (((y + size) < 254) & ((x + size) < 510)) {
do erase();
let size = size + 2;
do draw();
}
return;
}
/** Decrements the square size by 2 pixels. */
method void decSize() {
if (size > 2) {
do erase();
let size = size - 2;
do draw();
}
return;
}
/** Moves the square up by 2 pixels. */
method void moveUp() {
if (y > 1) {
do Screen.setColor(false);
do Screen.drawRectangle(x, (y + size) - 1, x + size, y + size);
let y = y - 2;
do Screen.setColor(true);
do Screen.drawRectangle(x, y, x + size, y + 1);
}
return;
}
/** Moves the square down by 2 pixels. */
method void moveDown() {
if ((y + size) < 254) {
do Screen.setColor(false);
do Screen.drawRectangle(x, y, x + size, y + 1);
let y = y + 2;
do Screen.setColor(true);
do Screen.drawRectangle(x, (y + size) - 1, x + size, y + size);
}
return;
}
/** Moves the square left by 2 pixels. */
method void moveLeft() {
if (x > 1) {
do Screen.setColor(false);
do Screen.drawRectangle((x + size) - 1, y, x + size, y + size);
let x = x - 2;
do Screen.setColor(true);
do Screen.drawRectangle(x, y, x + 1, y + size);
}
return;
}
/** Moves the square right by 2 pixels. */
method void moveRight() {
if ((x + size) < 510) {
do Screen.setColor(false);
do Screen.drawRectangle(x, y, x + 1, y + size);
let x = x + 2;
do Screen.setColor(true);
do Screen.drawRectangle((x + size) - 1, y, x + size, y + size);
}
return;
}
}
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