scale from center of screen

Programming Questions

clankill3r

in Programming Questions • 1 year ago

I want to scale from the center of the screen, but i don't want to use the scale() method.

What i have now works but there is probably a better way.

ArrayList<PVector> vectors = new ArrayList<PVector>();
void setup() {
vectors.add(new PVector(30, 30));
vectors.add(new PVector(70, 70));
}
void draw() {
background(255);
fill(0);
stroke(0);
float s = map(mouseX, 0, width, 0.5, 2);
for (PVector v : vectors) {
PVector tv = new PVector(v.x, v.y);
tv.x -= width/2;
tv.y -= height/2;
tv.mult(s);
tv.x += width/2;
tv.y += height/2;
ellipse(tv.x, tv.y, 5, 5);
}
}

Replies(3)

hellochar

Re: scale from center of screen

1 year ago

There isn't really, but using scale() actually isn't that bad. Since scale() always scales from the origin, we can translate everything such that the screen's center at (width/2, height/2) is temporarily at the origin, THEN do the scale, and finally translate everything back. So you'd do something like:

translate(-width/2, -height/2)

scale()

translate(+width/2, +height/2)

Kobby

Re: scale from center of screen

1 year ago

hellochar is right. scale() is the simplest method of doing it and occam's razor is a very good one to use :). You could also push and pop a matrix to get into a custom scaling set up and then return to ur original transform matrix

pushMatrix();
scale();
popMatrix();

clankill3r

Re: scale from center of screen

1 year ago

Problem is i need to draw lines to the 'scaled' thing after i'm done with scaling.

Not that my code in the first post is good for that, but it's easier to prepare that one.

thanks anyway

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