problem with scale

Programming Questions

mataarsak

in Programming Questions • 1 year ago

Idraw a rectangle in the screen and now I want to scale it , the problem is that when I add scale sometimes the rectangle disappeared and sometimes it jumps to somewhere else in the screen . should I add translate as well ?

I'm trying to learn how this scale works in diffrent situations .

void setup(){

size(200,200);

}

void draw() {

scale(2); // disappeared

rect(100,100,10,10);

}

Replies(1)

benja

Re: problem with scale

1 year ago

Hi,

scale() has effect on most drawing-commands.
In this case not only the values for height and width of the rectangle are multiplied by 2, the x-and y-coordinates are too.
so you could write as well:

rect(200, 200, 20, 20);

wich is outside of your sketch-window.

maybe this code helps illustrating what happens:

    void setup(){
    size(200,200);
    }
    void draw() {
      background(0);
      scale(map(mouseX, 0, width, 1, 2)); // disappeared
      rect(100,100,10,10);
    }

to avoid this behaviour you could use translate before and then draw the rectangle with rect(0,0,10,10),
or use a variables to define the height and width of your rectangle:

int w = 10;
int h = 10;
float scaleFactor =1;

void setup() {
size(200, 200);
}
void draw() {
background(0);
scaleFactor = (map(mouseX, 0, width, 1, 5));
rect(100, 100, w*scaleFactor, h*scaleFactor);
}

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