Processing 1.0 - Processing Discourse - smooth() function on the Reference

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smooth() function on the Reference (Read 978 times)

cavva

smooth() function on the Reference
Aug 18^th, 2006, 6:00pm

the example on the reference for the smooth function work in "Basic Mode".

I've tried to use it in "Continuous Mode" using Processing 0115 on OS X 10.3.9

Code:


void setup() {
  size(200, 200);
  background(255);
  smooth();
}

void draw() {
  
  fill(0);
  ellipse(70, 48, 36, 36);
}

and it doesn't work as i expected ... i need to move the background and smooth function into the draw function

Code:


void setup() {
  size(200, 200);

}

void draw() {
  background(255);
  smooth();
    
  fill(0);
  ellipse(70, 48, 36, 36);
}

why ?

flight404

Re: smooth() function on the Reference
Reply #1 - Aug 18^th, 2006, 6:25pm

In your first example, what you are doing is drawing a smoothed circle ontop of itself over and over and over and over. It shouldnt matter where you put the smooth call, but I would suggest keeping it in the setup loop. All you need to do is move the background() call into the beginning of your draw loop. That way, you never get overlapping ellipses.

Make sense?

Robert Hodgin {flight404}&&

cavva YaBB Newbies Offline Posts: 20	Re: smooth() function on the Reference Reply #2 - Aug 18^th, 2006, 7:16pm Ok, it work, thanks but i don't fully understand why overlapping always the same ellipse give me a non smooth ellipse

flight404

Re: smooth() function on the Reference
Reply #3 - Aug 19^th, 2006, 12:23am

It is because the pixels on the outside of the ellipse are anti-aliased, so that they can give the impression of being smooth with no jagged pixel edges. Constantly drawing that smooth ellipse on top of itself will have the effect of drawing over the anti-aliased edge over and over.

Remember, if you dont call background() in the draw loop, you will constantly be drawing ontop of what you drew since the applet started. Not unlike a painting.

If you add background() to the draw loop, it will wipe the canvas clean every time the draw method loops.

Robert Hodgin {flight404}&&

wxs

Re: smooth() function on the Reference
Reply #4 - Aug 19^th, 2006, 5:02am

cavva wrote on Aug 18^th, 2006, 7:16pm:

but i don't fully understand why overlapping always the same ellipse give me a non smooth ellipse

To expand on what flight404 said (in case it's not clear) an anti-aliased pixel is semi-transparent. If you draw a whole bunch of semi-transparent things of the same colour on top of eachother, eventually it will become opaque.
So if you have a white background, it anti-aliases the black circle by placing grey pixels around the edge. Once you do that a few times, they will all be black.

cavva YaBB Newbies Offline Posts: 20	Re: smooth() function on the Reference Reply #5 - Aug 19^th, 2006, 12:40pm thanks

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