# Direct orthonormed system
**URL:** https://discourse.processing.org/t/direct-orthonormed-system/2529
**Category:** Project Guidance
**Created:** [August 10, 2018, 11:54am UTC](https://discourse.processing.org/t/direct-orthonormed-system/2529 "2018-08-10T11:54:37Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@theo](https://discourse.processing.org/u/theo)
#### Post date: [August 10, 2018, 11:54am UTC](https://discourse.processing.org/t/direct-orthonormed-system/2529/1 "2018-08-10T11:54:37Z")
Hello,
By default the origin is in the top left corner, the x axis is pointing on the right and the y axis down.
Is it possible to get a “common” coordinate system (like the one usually used in math: origin bottom right corner, x axis pointing right and y axis pointing up)
I know the scale, rotate and translate function but my main problem is that I can’t scale the y axis by -1…
Thanks.
---
### Author:  [@jb4x](https://discourse.processing.org/u/jb4x)
#### Post date: [August 10, 2018, 12:18pm UTC](https://discourse.processing.org/t/direct-orthonormed-system/2529/2 "2018-08-10T12:18:42Z")
You can create a function that return the pixel coordinate based on your orthonormal system.
Let’s say you want your system to be
- 0 in the bottom left
- xMax in the bottom right
- yMax in the top left
Then a point (x, y) in your system would become ( (width / xMax) \* x, - (heigth / yMax) \* y) in the screen coordinate.
---
### Author:  [@hamoid](https://discourse.processing.org/u/hamoid)
#### Post date: [August 10, 2018, 1:41pm UTC](https://discourse.processing.org/t/direct-orthonormed-system/2529/3 "2018-08-10T13:41:17Z")
Why can’t you scale the y axis? It doesn’t work? Or your program should not do that?
```auto
translate(0, 100);
scale(1, -1);
rect(0, 0, 50, 50);
```
---
### Author:  [@theo](https://discourse.processing.org/u/theo)
#### Post date: [August 10, 2018, 3:48pm UTC](https://discourse.processing.org/t/direct-orthonormed-system/2529/4 "2018-08-10T15:48:01Z")
Ho! I never thought to it, this is a great idea, thank you jb4x
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### Author:  [@theo](https://discourse.processing.org/u/theo)
#### Post date: [August 10, 2018, 3:54pm UTC](https://discourse.processing.org/t/direct-orthonormed-system/2529/5 "2018-08-10T15:54:30Z")
hamoid, I tried to scale the y axis by -1 and translate but when I tried to draw sth, it was like if it didn’t work…
I will try again and informed you.
---
### Author:  [@ProcessingOrg](https://discourse.processing.org/u/ProcessingOrg)
#### Post date: [August 10, 2018, 6:48pm UTC](https://discourse.processing.org/t/direct-orthonormed-system/2529/6 "2018-08-10T18:48:30Z")
Here’s a more complete example to show @hamoid’s idea:
```auto
void setup() {
size(400, 400);
}
void draw() {
background(204);
translate(0, height);
scale(1, -1);
ellipse(0, 0, 50, 50);
ellipse(200, 200, 100, 100);
ellipse(200, 300, 10, 10);
}
```