CODEWITHSUNDEEP
css
Ciel
Ciel

Reputation: 4440

CSS - calc() on font-size - changing font size based on container size

I have a situation where I have a container element (div) that contains text. This text will sometimes be really large - not paragraph large, but it can potentially exceed the width of the text.

Obviously, in most situations it will just knock parts of the text to the next line, but I wanted to see if calc() can be used on font-size to change the size of the font to make sure it is always fitting within the bounds of the div it is in. Can this be done?

.name { width: 500px; font-size: 64px; }

<span class="name">Sometimes it is short</span>

<span class="name">Sometimes it is going to be really long, and people put long names</span>

I could just limit the number of letters people can use for a name - and to an extent I will, but I am curious to see if this can even be accomplished.

I found this post to do it with Javascript, but that was a long time ago, and I think CSS3 has a lot of new things that may let this be accomplished without any scripting. AutoFill

Upvotes: 19

Views: 82215

Answers (8)

Taiwei Tuan
Taiwei Tuan

Reputation: 1122

I met with the same problem. Since no existing answer in this thread can work, I overcame the challenges by using cqw.

cqw is now supported by most browsers as of 2024, except for a few less reputable browsers. https://caniuse.com/mdn-css_types_length_container_query_length_units

So, depending on the requirement, this will make at least 99% of end users happy.

Assume the container has the style --

.container {
  width: 100%;
  position: relative;
}

and the child has position: absolute, you will be able to make both banner re-sizable, AND font-size to change as the width of viewport changes with --

.child {
  position: absolute;
  left: 10%;
  top: 20.4%;  // Use percentage so it positions at relative place
  font-size: 2.35cqw;  
  line-height: 2.75cqw; // yes, it applies to other properties, too!
}

Upvotes: 1

Lee
Lee

Reputation: 31050

This can be done in pure css using the vi and vb properties.

https://developer.mozilla.org/en-US/docs/Web/CSS/length

These allow the font-size to be scaled in proportion to the container div's inline (vi) or block (vb) dimensions.

Presently supported on browsers covering ~92% of users (caniuse.com).

e.g.

.name { font-size: 0.5vi;}

Upvotes: 4

Marvin Danig
Marvin Danig

Reputation: 3908

Set the size of your container using vmin units, like so:


:root {
    --vmin: 1vmin;
    --container-length: calc(50 *var(--vmin));
    --factor: 6; /* Set the value according to the font size you want. */
}

.box {
    text-align: center;
    width: var(--container-length);
    height: var(--container-length); /* For a rectangle, use another variable and set the line height using that. */
    border: calc(var(--vmin)) solid black;
}
.box p {
    font-size: calc(var(--container-width) / var(--factor));
    line-height: 1.75;
}

That's it. Now your text will scale smoothly according to the container dimensions everywhere except on Safari, which has a jittery font scaling issue, but it does work anyway!).

Demo

If you want to learn more about --vmin based intrinsic typography, look at the Toucaan CSS framework that replaces all other CSS units like px, em, vw, rem, cqi, etc. completely.

Upvotes: 0

Farzad.Kamali
Farzad.Kamali

Reputation: 593

I recommend you to use text ellipsis

.name{
    width: 500px;
    font-size: 64px;
    text-overflow: ellipsis;
    overflow: hidden;
    display: block;
}

and if you need to control font-size, do it by @media in different devices

Upvotes: 0

Julio Rabadan
Julio Rabadan

Reputation: 181

Here a possible solution:

http://codepen.io/CrocoDillon/pen/fBJxu

p {
  margin: 0;
  font-size: calc(4vw + 4vh + 2vmin);
  /* See:
   * http://codepen.io/CrocoDillon/pen/jgmwt
   * For some math behind this
   */
}

Font-size is calculated with available size using a function that is not perfect, but may be adjusted to work well in some cases.

Upvotes: 18

ludiccc
ludiccc

Reputation: 353

Just a clarification:

if you use something like:

font-size: -webkit-calc(100% + 30px);
font-size:        -calc(100% + 30px);

what this does is add 30px to the 100% default font size, it can't be linked to the container width.

Although, you can do math there like:

font-size: -webkit-calc( 100% * 0.09479166667 - 6.666666669px );
font-size:        -calc( 100% * 0.09479166667 - 6.666666669px );

... but it will just calculate it against the 1em.

Upvotes: 1

unconditional_loading
unconditional_loading

Reputation: 161

Calc is still in it's infancy in terms of support & usefulness. By design it's really just there for doing simple math, like (100% - 20px). It really won't do the math complex enough to make the calculations possible. You are looking for a solution that will size the text based on the amount of space the letters physically take up horizontally (which depends on the letter's individual sizing) and the amount of space available for the containing div.

CSS is abstracted away from the actual element's contents, and it has no way to really discern if something currently "fits" or not. It can layout guidelines for how to handle things when they do or don't fit, but it can't adjust itself according to the content like you want it to. (It's not just you, we've all faced this problem or a similar version of it at some point.)

Check out Chris Coyer's post on what Calc might be handy for: http://css-tricks.com/a-couple-of-use-cases-for-calc/

Upvotes: 11

Josh Rutherford
Josh Rutherford

Reputation: 2723

This is still nearly impossible in CSS only, as the size of each character in different fonts isn't known to us via CSS. There is a jQuery plugin called fitText that handles this sort of thing very nicely.

Upvotes: 0

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