# Ellipse and trail

**URL:** <https://discourse.processing.org/t/ellipse-and-trail/39508>\
**Category:** Beginners\
**Created:** [October 30, 2022, 1:23pm UTC](https://discourse.processing.org/t/ellipse-and-trail/39508 "2022-10-30T13:23:56Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Ero](https://avatars.discourse-cdn.com/v4/letter/e/df705f/32.png) [@Ero](https://discourse.processing.org/u/Ero)\
**Post date:** [October 30, 2022, 1:23pm UTC](https://discourse.processing.org/t/ellipse-and-trail/39508/1 "2022-10-30T13:23:56Z")

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How can I make an ellipse that leaves behind a “trail”?

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**Author:** ![Chrisir](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/chrisir/32/45_2.png) [@Chrisir](https://discourse.processing.org/u/Chrisir)\
**Post date:** [October 30, 2022, 1:26pm UTC](https://discourse.processing.org/t/ellipse-and-trail/39508/2 "2022-10-30T13:26:14Z")

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You can use background (0, 10); so that the ellipses  
are overwritten but weakly

`ellipse(mouseX, mouseY, 6,6);`

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**Author:** ![glv](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/glv/32/18785_2.png) [@glv](https://discourse.processing.org/u/glv)\
**Post date:** [October 30, 2022, 2:38pm UTC](https://discourse.processing.org/t/ellipse-and-trail/39508/3 "2022-10-30T14:38:45Z")

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Hello @Ero,

There are resources (tutorials, references and examples) here:  
[https://processing.org/](https://processing.org/)

There is an example in there for this.

This will also work in a sketch with` draw()` and no `background()`:

```auto
  circle(frameCount, frameCount, 5);
  println(frameCount);
  fill(230, 5); // The 5 is alpha! Look this up in the color tutorial.
  rect (0, 0, width, height);

```

Have fun!

References:

- [https://processing.org/tutorials/color](https://processing.org/tutorials/color) \< transparence/alpha discussed here
- [https://processing.org/reference/draw\_.html](https://processing.org/reference/draw_.html)
- [https://processing.org/reference/background\_.html](https://processing.org/reference/background_.html)

`:)`

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<div class="post-metadata">

**Author:** ![glv](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/glv/32/18785_2.png) [@glv](https://discourse.processing.org/u/glv)\
**Post date:** [October 30, 2022, 2:40pm UTC](https://discourse.processing.org/t/ellipse-and-trail/39508/4 "2022-10-30T14:40:59Z")

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Hello @Chrisir,

> [@Chrisir](#):
>
> You can use background (0, 10);

You can’t use an alpha component with background().

There is a note about that here:  
[https://processing.org/reference/background\_.html](https://processing.org/reference/background_.html)

`:)`

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<div class="post-metadata">

**Author:** ![Chrisir](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/chrisir/32/45_2.png) [@Chrisir](https://discourse.processing.org/u/Chrisir)\
**Post date:** [October 30, 2022, 3:00pm UTC](https://discourse.processing.org/t/ellipse-and-trail/39508/5 "2022-10-30T15:00:24Z")

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Or use rect with fill(0,10);