website/content/blog/2015-04-16-responsive-layout-and-animation.md

---
id: 57
title: Responsive Layout and Animation
date: 2015-04-16T22:19:36+00:00
author: Brandon Rozek
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---
I saw [Mike Riethmuller’s](http://madebymike.com.au/) precision typography [pen](http://codepen.io/MadeByMike/pen/YPJJYv){.broken_link}, and was highly impressed. I think the equation used has other purposes as well

<!--more-->

Side Note: I changed the form of the equation to something similar to y = mx + b so that I can more easily recognize how it functions

#### Responsive Layout

There are many occasions where I want an element on the page to move between two points. The navigation in the header of my site (at the time of writing) is a great example of this. So knowing the two points I want it to lie between and having the screen width as the variable, I can plug in&#8230; [<img class="aligncenter size-full wp-image-58" src="https://brandonrozek.com/wp-content/uploads/2015/04/responsivelayoutequation.gif" alt="f(x) = (100 * (b - a)/(d - c))X + (ad - bc) / (d - c)" width="219" height="36" />](https://brandonrozek.com/wp-content/uploads/2015/04/responsivelayoutequation.gif){.broken_link} where a is the start pixel b is the end pixel c is the start media query d is the end media query and X is the screen width out of 100 otherwise known as 1vw \*\*Don&#8217;t forget to keep track of your units!! Whether it&#8217;s px/rem/em/etc.\*\* Say I want to push a box towards the right a minimum of 5px, a maximum of 20px and for the push to vary between the widths 400-800px. Then I would write&#8230;

```css
@media (min-width: 400px) and (max-width: 800px) {
    .box {
        position: relative;
        left: calc(3.75vw - 10px) /*After simplifying the equation*/ 
    }
}
```

That would only make it vary between 400-800px. Now we need to include what happens under 400px and over 800px.

```css
@media (max-width: 400px) {
    .box {
        position: relative;
        left: 5px;
    }
}

@media (min-width: 400px) and (max-width: 800px) {
    .box {
        position: relative;
        left: calc(3.75vw - 10px); 
    }
}

@media (min-width: 800px) {
    .box {
        position: relative;
        left: 20px; 
    }
}
```

This is exactly like Mike&#8217;s pen, but instead he uses the equation to adjust the font-size between an upper and lower bound. You can apply this method to anything that accepts calc() and viewport units. Here is my [pen](http://codepen.io/brandonrozek/pen/JoQVEb){.broken_link} showing some use cases. To make your life easier, I made a quick little tool where you can input the variables and it will provide you with a simpler form of the equation to put into your calc() function [here](http://codepen.io/brandonrozek/pen/KpPwGL){.broken_link}.

#### Animation

This is where the majority of my research went towards. It&#8217;s not as practical as say positioning an element is but I find it interesting. Like, what if I can manipulate the acceleration of the function? [<img class="aligncenter size-full wp-image-62" src="https://brandonrozek.com/wp-content/uploads/2015/04/accelerationequation.gif" alt="f(x) = ((b - a) / (d^n - c^n))X^n + (ad^n - bc^n) / (d^n - c^n) " width="202" height="36" />](https://brandonrozek.com/wp-content/uploads/2015/04/accelerationequation.gif){.broken_link} Where a is the start unit b is the end unit c is the start time d is the end time n is the acceleration modifier and X is time The interesting part of the function here is the n. If I keep n at 1, then the acceleration is constant. If it&#8217;s less than one, then it&#8217;s fast in the beginning and slows down at the end. If it&#8217;s greater than one, then it&#8217;s the opposite. I also made a little pen [here](http://codepen.io/brandonrozek/pen/RNzdOV){.broken_link} to demo this for you.

#### Conclusion

Having a function that goes between two points is incredibly handy. Now when it comes to positioning, I don&#8217;t have to guess which values match the design. If i cant something to be between here and there fluidly, I can do it. What about animation? Chaining them together should have an interesting affect&#8230; P.S For those of you crazy people who like to see the theory behind the math, (like myself) I have my scanned work [here](https://brandonrozek.com/2015/04/function-two-points-theory/).