Css - dynamic font size - css

We are developing a website for a school project: this website must also be available on mobile devices (and tablets).
We have attained this goal, except for an issue with the font-size: we've set this property manually via #media query.
Does there exist a way by make the font-size can be made dynamic without the use of percent?
Thanks

If I understand your question, you should consider this option:
.yourClass {
font-size: 2.0vw;
}
It meaning 2.0% of viewport width. You can also use 2.0vh (2.0% viewport height)

I'm not sure how others would feel about this solution (since some will view it as unnecessary scripting), but it works really well for me. I use jQuery to set font sizes as a percentage of the screen size.
var FONT_SCALE = 0.027;
function initFontSizes() {
$(".text-element").css("font-size", $(window).height() * FONT_SCALE);
}
If you wanted you could add it as a jQuery function so you can call it on any object:
jQuery.fn.setFontSize(scale) {
$(this).css("font-size", $(window).height() * scale);
}

If you wanted to muddy the waters with a bit of javascript, you could go for something along the lines of:
$(function(){
resizeFont();
$(window).resize(function(){
resizeFont();
});
function resizeFont(){
var windowWidth = $(window).width(),
psize = windowWidth/ 10;
$("p").css("font-size",psize);
}
});
You'd need to a bit of maths to sort it out properly though.
http://jsfiddle.net/wildandjam/5Hnxa/

Related

How does a child scale font-size contingent on the parent? [duplicate]

This question already has answers here:
Font scaling based on size of container
(41 answers)
Closed 1 year ago.
I have a container that has a % width and height, so it scales depending on external factors. I would like the font inside the container to be a constant size relative to the size of containers. Is there any good way to do this using CSS? The font-size: x% would only scale the font according to the original font size (which would be 100%).
If you want to set the font-size as a percentage of the viewport width, use the vwunit:
#mydiv { font-size: 5vw; }
The other alternative is to use SVG embedded in the HTML. It will just be a few lines. The font-size attribute to the text element will be interpreted as "user units", for instance those the viewport is defined in terms of. So if you define viewport as 0 0 100 100, then a font-size of 1 will be one one-hundredth of the size of the svg element.
And no, there is no way to do this in CSS using calculations. The problem is that percentages used for font-size, including percentages inside a calculation, are interpreted in terms of the inherited font size, not the size of the container. CSS could use a unit called bw (box-width) for this purpose, so you could say div { font-size: 5bw; }, but I've never heard this proposed.
Another js alternative:
Working Example
fontsize = function () {
var fontSize = $("#container").width() * 0.10; // 10% of container width
$("#container h1").css('font-size', fontSize);
};
$(window).resize(fontsize);
$(document).ready(fontsize);
Or as stated in torazaburo's answer you could use svg. I put together a simple example as a proof of concept:
SVG Example
<div id="container">
<svg width="100%" height="100%" viewBox="0 0 13 15">
<text x="0" y="13">X</text>
</svg>
</div>
You may be able to do this with CSS3 using calculations, however it would most likely be safer to use JavaScript.
Here is an example: http://jsfiddle.net/8TrTU/
Using JS you can change the height of the text, then simply bind this same calculation to a resize event, during resize so it scales while the user is making adjustments, or however you are allowing resizing of your elements.
I used Fittext on some of my projects and it looks like a good solution to a problem like this.
FitText makes font-sizes flexible. Use this plugin on your fluid or responsive layout to achieve scalable headlines that fill the width of a parent element.
It cannot be accomplished with css font-size
Assuming that "external factors" you are referring to could be picked up by media queries, you could use them - adjustments will likely have to be limited to a set of predefined sizes.
Here is the function:
document.body.setScaledFont = function(f) {
var s = this.offsetWidth, fs = s * f;
this.style.fontSize = fs + '%';
return this
};
Then convert all your documents child element font sizes to em's or %.
Then add something like this to your code to set the base font size.
document.body.setScaledFont(0.35);
window.onresize = function() {
document.body.setScaledFont(0.35);
}
http://jsfiddle.net/0tpvccjt/
I had a similar issue but I had to consider other issues that #apaul34208 example did not tackle. In my case;
I have a container that changed size depending on the viewport using media queries
Text inside is dynamically generated
I want to scale up as well as down
Not the most elegant of examples but it does the trick for me. Consider using throttling the window resize (https://lodash.com/)
var TextFit = function(){
var container = $('.container');
container.each(function(){
var container_width = $(this).width(),
width_offset = parseInt($(this).data('width-offset')),
font_container = $(this).find('.font-container');
if ( width_offset > 0 ) {
container_width -= width_offset;
}
font_container.each(function(){
var font_container_width = $(this).width(),
font_size = parseFloat( $(this).css('font-size') );
var diff = Math.max(container_width, font_container_width) - Math.min(container_width, font_container_width);
var diff_percentage = Math.round( ( diff / Math.max(container_width, font_container_width) ) * 100 );
if (diff_percentage !== 0){
if ( container_width > font_container_width ) {
new_font_size = font_size + Math.round( ( font_size / 100 ) * diff_percentage );
} else if ( container_width < font_container_width ) {
new_font_size = font_size - Math.round( ( font_size / 100 ) * diff_percentage );
}
}
$(this).css('font-size', new_font_size + 'px');
});
});
}
$(function(){
TextFit();
$(window).resize(function(){
TextFit();
});
});
.container {
width:341px;
height:341px;
background-color:#000;
padding:20px;
}
.font-container {
font-size:131px;
text-align:center;
color:#fff;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div class="container" data-width-offset="10">
<span class="font-container">£5000</span>
</div>
https://jsfiddle.net/Merch80/b8hoctfb/7/
I've given a more detailed answer of using vw with respect to specific container sizing in this answer, so I won't just repeat my answer here.
In summary, however, it is essentially a matter of factoring (or controlling) what the container size is going to be with respect to viewport, and then working out the proper vw sizing based on that for the container, taking mind of what needs to happen if something is dynamically resized.
So if you wanted a 5vw size at a container at 100% of the viewport width, then one at 75% of the viewport width you would probably want to be (5vw * .75) = 3.75vw.
If you want to scale it depending on the element width, you can use this web component:
https://github.com/pomber/full-width-text
Check the demo here:
https://pomber.github.io/full-width-text/
The usage is like this:
<full-width-text>Lorem Ipsum</full-width-text>
You can also try this pure CSS method:
font-size: calc(100% - 0.3em);

Pure CSS parallaxing (not fixed) background for single row in layout

I'm wondering if it's possible to use only CSS to create a parallax scrolling background that meets the following specifications.
It works on an element that sits inside an otherwise static layout (i.e. my whole page layout isn't a group of parallaxing items)
The background isn't entirely fixed in place; it moves, just not as fast as the rest of the page.
I've looked up tons of tutorials for parallaxing backgrounds, and have found some seemingly great tutorials, but they all have one of the following problems.
They rely on the whole page being a parallax group so that you're actually scrolling over a container via an "overflow: auto" specification
The background is totally fixed in place
they use JavaScript.
Sooo, I can accomplish what I want with JavaScript fairly easily. Here's a full working example on JSFiddle that you can try out.
CSS
.parallax-row {
background-image: url(http://lorempixel.com/output/nature-q-c-781-324-3.jpg);
background-size: auto 150%;
}
JavaScript
/**
* Update the parallaxing background img to partially scroll
*/
jQuery(document).ready(function($) {
$(window).on('scroll', function() {
$('.parallax-row').each(function(index, el) {
var $el = $(el);
var fromTop = $el.offset().top + ($el.outerHeight() / 2) - $(window).scrollTop();
var windowHeight = $(window).height();
var percent = (fromTop * 100 / windowHeight);
$el.css('background-position', '0 ' + percent + '%');
});
});
});
Is it possible to accomplish that same effect with just CSS?

How to create vertical "pages" where each page is height of the viewport using Bootstrap and Angular?

I am using Angular 1.3 and Bootstrap 3.2. I want to create a single webpage that does exactly this: http://lewisking.net. i.e. I want to be able to have vertically stacked divs that are the height of the viewport. I'm thinking of making a directive that watches the browser height/width and updates the style accordingly.
Any other ideas? Any tips for implementing with a directive?
This is the perfect use case for vh and vw.
Simply set:
.wrapper {
width: 100vw;
height: 100vh;
}
And it will work out the box. If you have to support any old browsers you can easily do a quick JS fall back.
CSS will get you part of the way, but you will need JS to update your 100% height on resize
and scrollTop points etc. And you will also need a way to animate the scroll anyway. This isn't exactly what I would do but it explains the basic idea.
$($window).on('resize', function() {
$scope.winWidth = $(window).width();
$scope.winHeight = $(window).height();
});
...
$scope.getSectionStyle = function(){
return {width:$scope.winWidth, height:$scope.winHeight} ;
}
...
<section id="sectionId" ng-style="getSectionStyle()"
To animate the scroll I just use jQuery like. If you're a angular purist there is $achorScoll but it has no animating at this point so you need to do some extra factory or directive like https://github.com/durated/angular-scroll/
$rootScope.scrollTo = function(_to){
$("html, body").delay(300).animate({scrollTop:_to},{ easing: "easeOutExpo"}, 2000);
}
To get _to you just find the elements offset().top something like :
var offset = $('#sectionId').offset();
$rootScope.scrollTo(offset.top);

WP8 IE10 viewport issue

Did any of you noticed that when using -ms-viewport (with specific width of 320px or device-width) then web browser content can be moved outside available space? It seems like document size is wrong so i can scroll it's content to the left but there is nothing then white empty space. I can also zoom it out(but i should not) and it's size after that is not always the same. I'm aware of http://mattstow.com/responsive-design-in-ie10-on-windows-phone-8.html but it does not help. It happens after second or third navigate to the same content and disappears for example when device is rotated.
Windows Phone 8 does not properly recognize the meta viewport tag that is standard for webkit and mobile web.
Try this in your CSS
#-ms-viewport{width:device-width}
And then add this JS
if (navigator.userAgent.match(/IEMobile\/10\.0/)) {
var msViewportStyle = document.createElement("style");
msViewportStyle.appendChild(
document.createTextNode(
"#-ms-viewport{width:auto!important}"
)
);
document.getElementsByTagName("head")[0].
appendChild(msViewportStyle);
}
More here (credit)
try adding the following
#-ms-viewport {
user-zoom: fixed;
max-zoom: 1;
min-zoom: 1;
}

Autosize Text Area (Multiline asp:TextBox)

I have a MultiLine asp:Textbox (a standard html textarea for those non-asp people) that I want to be auto-sized to fit all it's content only through css. The reason for this is that I want it to be of a specified height in the web browser, with scrolling enabled.
I have implemented a print style sheet however and want all text located in the textarea to be displayed when printed with no overflow hidden.
I can manually specify the height of the textarea in the print.css file problem with this being that the fields are optional and a 350px blank box is not optimal and there is always the possibility of a larger amount of text than this...
I have tried using :
height: auto;
height: 100%;
In IE and Firefox respectively yet these seem to be overridden by the presence of a specified number of rows in the html mark-up for the form which must be generated by .NET when you do not specify a height on the asp:Textbox tag, this seems to only accept numercial measurements such as px em etc...
Any ideas?
What you are asking for (a css solution) is not possible.
The content of the textarea is not html elements, so it can not be used by css to calculate the size of the textarea.
The only thing that could work would be Javascript, e.g. reading the scrollHeight property and use that to set the height of the element. Still the scrollHeight property is non-standard, so it might not work in all browsers.
jQuery or a javascript function to find and make textboxes bigger might be the best solution - at least thats what i found
we use this set of functions and call clean form after the page is loaded (i know this isnt the best solution right here and am working to transfer to a jQuery solution that is more elegant) - one note make sure your textareas have rows and cols specified or it doesnt work right.
function countLines(strtocount, cols)
{
var hard_lines = 1;
var last = 0;
while (true)
{
last = strtocount.indexOf("\n", last + 1);
hard_lines++;
if (last == -1) break;
}
var soft_lines = Math.round(strtocount.length / (cols - 1));
var hard = eval("hard_lines " + unescape("%3e") + "soft_lines;");
if (hard) soft_lines = hard_lines; return soft_lines;
}
function cleanForm()
{
var the_form = document.forms[0];
for (var i = 0, il = the_form.length; i < il; i++)
{
if (!the_form[i]) continue;
if (typeof the_form[i].rows != "number") continue;
the_form[i].rows = countLines(the_form[i].value, the_form[i].cols) + 1;
}
setTimeout("cleanForm();", 3000);
}
If you set rows to be a ridiculously high number the CSS height rule should override it on the screen.
Then in the print stylesheet just set height to auto. This might result in some big blank space where all the available rows haven't been filled up, but at least all text will be visible.
give jQuery's autogrow() a go #
http://plugins.jquery.com/project/autogrow

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