How to move the cursor with arrow keys?

General Discussion Other

aahoang

How to move the cursor with arrow keys?

in General Discussion • Other • 5 months ago

Hi I'm making a drawing program and I want to be able to draw with the arrow keys, which is basically moving the cursor with the keys. Any help would be appreciated

Replies(4)

asimes

Re: How to move the cursor with arrow keys?

5 months ago

This is the basic idea:

int x, y;
void setup() {
size(400, 400);
x = width/2;
y = height/2;
}
void draw() {
background(255);
ellipse(x, y, 30, 30);
}
void keyPressed() {
if (key == CODED) {
if (keyCode == UP) y--;
if (keyCode == RIGHT) x++;
if (keyCode == DOWN) y++;
if (keyCode == LEFT) x--;
}
}

I'm sure you'll notice it is unbearably slow. One obvious trick would be to make x or y change by more than 1, but a different method would be to have the keyPresses set a flag to true (for example, a boolean named "upHeld"). Then in the draw loop, if the flag is set, have x or y move.

PhiLho

Re: How to move the cursor with arrow keys?

5 months ago

In this case, using keyPressed in draw() is better, supporting continuous moves:

int x, y;
void setup() {
size(400, 400);
x = width/2;
y = height/2;
}
void draw() {
background(255);
ellipse(x, y, 30, 30);
if (keyPressed) {
if (key == CODED) {
if (keyCode == UP) y--;
if (keyCode == RIGHT) x++;
if (keyCode == DOWN) y++;
if (keyCode == LEFT) x--;
}
}
}

aahoang

Re: How to move the cursor with arrow keys?

5 months ago

thanks guys, both input were very helpful and i got the job done

asimes

Re: How to move the cursor with arrow keys?

5 months ago

*Face-palm* I should have seen that PhiLho, ha ha

It occurred to me after trying it, how does one go about receiving two arrow keys at once in Processing?

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