# Points appearing "transparent"

**URL:** <https://discourse.processing.org/t/points-appearing-transparent/7729>\
**Category:** Coding Questions\
**Created:** [January 22, 2019, 8:39am UTC](https://discourse.processing.org/t/points-appearing-transparent/7729 "2019-01-22T08:39:16Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Sarah](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/sarah/32/1675_2.png) [@Sarah](https://discourse.processing.org/u/Sarah)\
**Post date:** [January 22, 2019, 8:39am UTC](https://discourse.processing.org/t/points-appearing-transparent/7729/1 "2019-01-22T08:39:16Z")

</div>

When I’ve tried drawing points using a for loop to cover the screen it doesn’t appear to be completely solid:

```auto
size(255, 255);

noStroke();
fill(255, 0, 0);
ellipse(100, 100, 100, 100);

for (int i = 0; i < 255; i++) {
  for (int j = 0; j < 255; j++) {
    stroke(255);
    point(i, j);
  }
}

```

For me, the circle is still visible in the background. This can be easily fixed by changing the `strokeWeight`, but it seems like the points should cover the entire screen with no gaps.

Strangely, when I change the renderer to `P2D`, the program seems to work properly.

Does this appear for anyone else, and is this the expected behavior?

---

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**Author:** ![TfGuy44](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/tfguy44/32/41_2.png) [@TfGuy44](https://discourse.processing.org/u/TfGuy44)\
**Post date:** [January 22, 2019, 9:19am UTC](https://discourse.processing.org/t/points-appearing-transparent/7729/2 "2019-01-22T09:19:01Z")

</div>

This is the correct behavior. The problem is that what you consider a properly drawn point is not the same as what some renderers consider a properly drawn point.

Forget about points for a second. Imagine you want to draw a circle. Easy, right? WRONG! Since the screen is made up of pixels, it’s NEARLY IMPOSSIBLE to just draw a circle by having some pixels be the color of the circle and the other pixels be whatever color they were before. Imagine trying to draw a circle with a diameter of three pixels - it would looks like a 3x3 pixel SQUARE! Yikes!

… Except it doesn’t. And the reason it doesn’t is because a tiny, diameter=3 circle isn’t drawn of 9 pixels - the edges of it are blurred slightly to smooth them out. In fact, ALL circles that get drawn are smoothed out a little bit. This is the default setting, and usually it happens just fine without you needing to worry about it.

… Now back to these points. Image that they are not points, but circles of diameter=1. Because of this secret smoothing/blurring that is happening to make their edges not look jagged and square, they don’t completely fill a whole pixel each. In fact, they might only slightly effect a few pixels near where the point is supposed to be.

In any case, this automatic smoothing is ruining the totally-cover-up-the-red-circle effect you are trying to get. Thankfully, you can disable this secret smoothing by calling `noSmooth();`

* * *

TLDR: Add a call to `noSmooth();` on the line after `size();`. This will make your points take up a whole pixel, and your circle will be covered as you expect.

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<div class="post-metadata">

**Author:** ![GoToLoop](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/gotoloop/32/86_2.png) [@GoToLoop](https://discourse.processing.org/u/GoToLoop)\
**Post date:** [January 22, 2019, 9:32am UTC](https://discourse.processing.org/t/points-appearing-transparent/7729/3 "2019-01-22T09:32:11Z")

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> [@TfGuy44](#):
>
> Add a call to `noSmooth();` on the line after `size();`.

Alternatively, replace **point()** w/ **set()**: `set(i, j, -1);`

> **[set() / Reference](https://processing.org/reference/set_.html)**
>
> Changes the color of any pixel or writes an image directly into the display window. The x and y parameters specify the pixel to change and the color parameter specifies…

Or change `pixels[]` directly: [pixels[] / Reference / Processing.org](http://Processing.org/reference/pixels.html)

```java
loadPixels();
java.util.Arrays.fill(pixels, -1);
updatePixels();

```

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<div class="post-metadata">

**Author:** ![Sarah](https://yyz2.discourse-cdn.com/flex036/user_avatar/discourse.processing.org/sarah/32/1675_2.png) [@Sarah](https://discourse.processing.org/u/Sarah)\
**Post date:** [January 22, 2019, 10:28pm UTC](https://discourse.processing.org/t/points-appearing-transparent/7729/4 "2019-01-22T22:28:55Z")

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Thanks for your replies, I completely forgot that points were rendered circularly! 😶