I'm using less.css as css preprocessor, and i was wonder if it is possible to print out media queries using less.css loops.
I've tried a very basic example loop:
#iterations: 30;
.loopingClass (#index) when (#index > 0) {
(~".myclass_#{index}") {
font-size: -#index px;
}
.loopingClass(#index - 1);
}
.loopingClass (0) {}
.loopingClass (#iterations);
but this will end up creating a class.
According to this example:
http://codepen.io/ericrasch/pen/HzoEx?editors=110
we can create media queries in less using this syntax:
#mobile: ~"only screen and (max-width: 529px)";
body {
#media #mobile {
background: orange;
content: "mobile";
}
}
But, as you can see, the media query value is a variable and not a class. So my question is, can i use less.css loop to print out media queries value as variable instead of classes? Or there's any workaround for this issue?
Thanks in advance
Related
I'm trying to "translate" a sass function into a less function.
Here is the original SASS one :
#mixin bp($feature, $value) {
// Set global device param
$media: only screen;
// Media queries supported
#if $mq-support == true {
#media #{$media} and ($feature: $value) {
#content;
}
// Media queries not supported
} #else {
#if $feature == 'min-width' {
#if $value <= $mq-fixed-value {
#content;
}
} #else if $feature == 'max-width' {
#if $value >= $mq-fixed-value {
#content;
}
}
}
}
And here is the function I started to make in less as it seems every declaration can not be implemented the same as in sass :
.bp(#feature; #val) when (#mq-support = true) {
#med: ~"only screen";
#media #{med} and (#{feature}:#val) {
#content;
}
}
When I'm compiling this, I got the following error :
Missing closing ')' on line 15, column 34:
15 #media #{med} and (#{feature}:#val) {
16 #content;
So this error seems to come from the closing #{feature} closing bracket but following the documentation and several blog posts on the internet, it seems that since the 1.6.0 version of less, the css property interpolation is a feature that should work.
Does anybody have an idea of what could be wrong here ?
Is it actually possible to use a variable as a property in a media query ?
Maybe I'm doing it totally wrong but it seems the mixins guard feature in less does not work exactly the same as with SASS and the #if condition so the "translation" is a little bit different.
Thank you in advance
Sébastien
Interpolation or using variables in media queries work slightly differently in Less.
First of all, you shouldn't use the normal interpolation syntax (#{med}). Instead it should just be #med.
Next the second condition should also be set to a variable and then appended to the media query just like the #med variable or it should be included as part of the #med variable itself. I've given a sample for both approaches below.
.bp(#feature; #val) when (#mq-support = true) {
#med: ~"only screen and";
#med2: ~"(#{feature}:#{val})";
#media #med #med2{
#content();
}
}
or
.bp(#feature; #val) when (#mq-support = true) {
#med: ~"only screen and (#{feature}:#{val})";
#media #med {
#content();
}
}
Below is a sample conversion of that Sass code completely into its Less equivalent. Less does not support the #content like in Less, so it should be passed as a detached ruleset with the mixin call.
#mq-support: true;
#mq-fixed-value: 20px;
.bp(#feature; #val; #content) {
& when (#mq-support = true) {
#med: ~"only screen and (#{feature}:#{val})";
#media #med {
#content();
}
}
& when not (#mq-support = true) {
& when (#feature = min-width) {
& when (#val <= #mq-fixed-value){
#content();
}
}
& when (#feature = max-width) {
& when (#val >= #mq-fixed-value){
#content();
}
}
}
}
a{
.bp(max-width, 100px, { color: red; } );
}
b{
.bp(min-width, 10px, { color: blue; } );
}
I'm trying to use LESS to dynamically generate a set of mixins that would help me write cleaner media query code. So far in my limited knowledge of the language I've put together code that looks like this:
#sizes: xxs, xs, sm, md, lg;
.mediaQueries(#iterator:1) when(#iterator <= length(#sizes)) {
//Extract name
#sizeName: extract(#sizes, #iterator);
//Attempt to build min-width query
.MQ-min-#{sizeName} (#content) {
#media (min-width: #screen-#{sizeName}) {
#content();
}
}
//Attempt to build max-width query
.MQ-max-#{sizeName} (#content) {
#media (max-width: #screen-#{sizeName}) {
#content();
}
}
.mediaQueries((#iterator + 1));
}
.mediaQueries();
The goal is to have a set of mixins that would allow me to easily and cleanly define some CSS properties for a specific breakpoint, like so:
.generic-class {
background: black;
//Sizes #screen-sm and up
.MQ-min-sm({
background: transparent;
})
}
It doesn't work. Something to note, I'm trying to interpolate the size name into a variable name that would then output me a the px value of that variable into the #media query. Is something like this even possible?
Otherwise my compiler currently breaks on the start of the nested mixin (.MQ-min-#{sizeName} (#content) {) with the error:
Potentially unhandled rejection [2] Missing closing ')' in file ../mixins.less line no. 43
Is something like what I'm trying to achieve possible?
I think the simplest way for you to achieve this is by using a single parametric mixin like given below. This avoids the need for all those iterations, dynamic mixin creations etc.
#sizes: xxs, xs, sm, md, lg;
#screen-xxs: 100px;
#screen-sm: 200px;
.MQ(#content, #sizeName, #max-min) { /* get ruleset, size name and min/max as input */
#selector: ~"(#{max-min}-width: #{screen-#{sizeName}})"; /* form the media selector */
#media #selector { /* use it */
#content();
}
}
.generic-class {
background: black;
.MQ({
background: transparent;
}, /* ruleset */
sm, /* screen size */
max /* min/max */
);
}
If the mixins are for your own usage then this is all that you need. If it is for distribution as library then you may want to put some guards on #sizeName and #max-min variables to restrict invalid values.
Note: Less compiler always had a problem with the interpolation here - #media (min-width: #screen-#{sizeName}) also (I am not sure if it has been addressed) and that's why I created a temp variable.
EDIT: RESOLVED
I am working on a way to easily write LESS code that takes parameters but still works with media queries. This is turning out to be rather convoluted, but I have gotten it working – on all sizes except one. The medium and large sizes work, but small is for some reason not printing the parameter, leaving me with css like font-size: ;.
Here I define my media sizes:
#m-small = ~"screen and (max-width: 799px)";
#m-medium = ~"screen and (min-width: 800px) and (max-width: 1299px)";
#m-large = ~"screen and (min-width: 1300px)";
Then, the main function I call, where #attr is the CSS property (e.g. font-size) and #parameter is the variable (e.g. fs-medium). To use this, I can write .media('font-size', 'fs-medium'), which is significantly less verbose than defining every media query.
Edit: There was a bug here, hence the problem; I have fixed it.
.media(#attr, #parameter) {
#media #m-small {
.small(#attr, #parameter);
}
#media #m-medium {
.medium(#attr, #parameter);
}
#media #m-large {
.large(#attr, #parameter);
}
}
These functions store the default values for parameters at various sizes, allowing me to consolidate where I define my variables, grouped by media query:
.small(#attr, #parameter) {
#fs-small : 1.4rem;
#fs-medium : 2.0rem;
#fs-large : 3.4rem;
#logo-width : 10rem;
.guards();
}
.medium(#attr, #parameter) {
#fs-small : 1.4rem;
#fs-medium : 2.4rem;
#fs-large : 3.8rem;
#logo-width : 12rem;
.guards();
}
.large(#attr, #parameter) {
#fs-small : 1.4rem;
#fs-medium : 1.8rem;
#fs-large : 5rem;
#logo-width : auto;
.guards();
}
In the above code, I call .guards() to render the content. This checks through my list of guards for one with a matching attribute, because LESS does not allow variables to be used in CSS property names. In these guards, I dynamically call the parameter, so that if I passed fs-medium, it will render #fs-medium's value.
.guards() when (#attr = 'font-size') {
font-size: ##parameter;
}
.guards() when (#attr = 'width') {
width: ##parameter;
}
Now, as I said, this works fine for the medium and large sizes, so I feel like there is either a typo in my code (I've checked) or a bug in LESS. One piece of code that uses this is as follows:
nav {
.media('font-size', 'fs-medium');
}
Which renders the following content:
#media screen and (max-width: 799px){
nav{ font-size:; }
}
#media screen and (min-width: 800px) and (max-width: 1299px){
nav{ font-size:2.4rem; }
}
#media screen and (min-width: 1300px){
nav{ font-size:1.8rem; }
}
Why is the small font-size missing?
I have discovered that I do indeed have a typo in my question, where I typed 'paremeter' under the .small mixin. I have edited it in the original post, but I am leaving it here for others trying to use media queries in LESS in a generalized way.
Verdict: typo.
I'm experimenting with LESS (not a fan of the SASS syntax) and have been trying to find out what the best way to do media queries with it would be.
I read through this blog post on how to "do" media queries with LESS, but it points out the fact that this causes all the media queries to be separated and scattered throughout the resulting CSS. This doesn't really bother me (I could care less about the result and more about it working). What did bother me was a comment that talked about issues when viewing from iOS devices and the commenter found that once the media queries were consolidated the issue was resolved.
Has anyone found a good solution for using media queries with LESS?
The way I invision this working would be something like...
//Have an overall structure...
.overall(){
//Have ALL your CSS that would be modified by media queries and heavily use
//variables that are set inside of each media queries.
}
#media only screen and (min-width: 1024px){
//Define variables for this media query (widths/etc)
.overall
}
I understand that there could be some issues with this, but the current setup doesn't seem to be that beneficial.
So I guess my question is if there have been any good solutions/hacks to allow for grouped media queries?
(Just incase it matters I use dotless as the engine to parse my .less files)
First, your solution given in the question certainly has some usefulness to it.
One thing I thought, however, was that it would be nice to define all the media query variables "near" one another (your solution would have them under each media query call). So I propose the following as an alternative solution. It also has drawbacks, one being perhaps a bit more coding up front.
LESS Code
//define our break points as variables
#mediaBreak1: 800px;
#mediaBreak2: 1024px;
#mediaBreak3: 1280px;
//this mixin builds the entire media query based on the break number
.buildMediaQuery(#min) {
#media only screen and (min-width: #min) {
//define a variable output mixin for a class included in the query
.myClass1(#color) {
.myClass1 {
color: #color;
}
}
//define a builder guarded mixin for each break point of the query
//in these is where we change the variable for the media break (here, color)
.buildMyClass1() when (#min = #mediaBreak1) {
.myClass1(red);
}
.buildMyClass1() when (#min = #mediaBreak2) {
.myClass1(green);
}
.buildMyClass1() when (#min = #mediaBreak3) {
.myClass1(blue);
}
//call the builder mixin
.buildMyClass1();
//define a variable output mixin for a nested selector included in the query
.mySelector1(#fontSize) {
section {
width: (#min - 40);
margin: 0 auto;
a {
font-size: #fontSize;
}
}
}
//Again, define a builder guarded mixin for each break point of the query
//in these is where we change the variable for the media break (here, font-size)
.buildMySelector1() when (#min = #mediaBreak1) {
.mySelector1(10px);
}
.buildMySelector1() when (#min = #mediaBreak2) {
.mySelector1(12px);
}
.buildMySelector1() when (#min = #mediaBreak3) {
.mySelector1(14px);
}
//call the builder mixin
.buildMySelector1();
//ect., ect., etc. for as many parts needed in the media queries.
}
}
//call our code to build the queries
.buildMediaQuery(#mediaBreak1);
.buildMediaQuery(#mediaBreak2);
.buildMediaQuery(#mediaBreak3);
CSS Output
#media only screen and (min-width: 800px) {
.myClass1 {
color: #ff0000;
}
section {
width: 760px;
margin: 0 auto;
}
section a {
font-size: 10px;
}
}
#media only screen and (min-width: 1024px) {
.myClass1 {
color: #008000;
}
section {
width: 984px;
margin: 0 auto;
}
section a {
font-size: 12px;
}
}
#media only screen and (min-width: 1280px) {
.myClass1 {
color: #0000ff;
}
section {
width: 1240px;
margin: 0 auto;
}
section a {
font-size: 14px;
}
}
For responsive Wordpress sites I use a starter theme called Bones by Eddie Machado ( http://themble.com/bones/ ). I rather like the way it uses media queries, it has different stylesheets for different breakpoints (480+, 768+ etc) which you can change depending on your design.
It then imports these with #import into one stylesheet underneath the appropriate media queries. You edit all of these in LESS and, I use Simpless by Kiss ( http://wearekiss.com/simpless ) to compile my .less stylesheets into .css automatically. I really find it a really good starting point for developing a simple responsive site. Even if you're not developing in Wordpress you may want to check out how they're structured their media queries as it all seems to work fine even with the use if LESS.
I recently implemented this technique with SASS 3.2 using #content blocks on a project I've been working on, and I've just gotten to the point where I need to include support for older browsers such as IE7 and 8.
Example:
.overview {
padding: 0 0 19px;
#include respond-to(medium-screens) {
padding-top: 19px;
} //medium-screens
#include respond-to(wide-screens) {
padding-top: 19px;
} //medium-screens
}
They both don't support media queries, and I've often handled this in the past by serving up all styles to these browsers when I had my media queries separated into separate partial files such as _320.scss, _480.scss and in my IE stylesheet loading them like so:
#import 320.scss;
#import 480.scss;
etc.
Which would load all styles, and always assign IE7 - 8 a 940px (or whatever the max width is) layout and styles. By nesting styles in SASS 3.2 inline like this, it eliminates the need for separate partial stylesheets, but totally screws up how I load styles for IE.
Any ideas or solutions on how to combat this? I could use a polyfill such as respond.js to force IE to use media queries, but would prefer to just serve up a non-flexible site to IE.
Any ideas on either how to best organize these files, or a better solution?
You can generate a separate stylesheet for IE<9 that contains everything your normal sheet has, but with flattened media queries based on a set width.
Full explanation here http://jakearchibald.github.com/sass-ie/, but basically you have this mixin:
$fix-mqs: false !default;
#mixin respond-min($width) {
// If we're outputting for a fixed media query set...
#if $fix-mqs {
// ...and if we should apply these rules...
#if $fix-mqs >= $width {
// ...output the content the user gave us.
#content;
}
}
#else {
// Otherwise, output it using a regular media query
#media screen and (min-width: $width) {
#content;
}
}
}
Which you'd use like this:
#include respond-min(45em) {
float: left;
width: 70%;
}
This would be inside all.scss, which would compile down to all.css with media queries. However, you'd also have an additional file, all-old-ie.scss:
$fix-mqs: 65em;
#import 'all';
That simply imports all, but flattens media query blocks given a fake width of 65em.
I use LESS for a lot of my work, but on larger projects, with many people working across files, I don't like using breakpoint files, such as 1024.less.
My and my team use a modular approach, such as header.less which contains all the code for just the header, including the associated breakpoints.
To get round IE problems (we work in a corporate environment), I use this approach:
#media screen\9, screen and (min-width: 40em) {
/* Media queries here */
}
The code inside the media query is always executed by IE7 and less. IE9 and above obeys the media queries like a proper browser should. The problem is IE8. To solve this, you need to make it behave like IE7
X-UA-Compatible "IE=7,IE=9,IE=edge"
I've found this doesn't always work if set in the metatags in the HTML, so set it using the server headers.
See the gist here:
https://gist.github.com/thefella/9888963
Making IE8 act like IE7 isn't a solution that works for everyone, but it suits my needs.
Jake Archibald has the best technique I've seen to date for achieving this. This technique automatically creates a separate stylesheet for IE, with all the same styles inside of your media queries but without the media query itself.
I also campaigned to get this technique built into the popular breakpoint extension for Sass, if you're interested in using that!
If you wanted to keep everything under one roof and only have a single http request for your older browser visitors you could do something like this
Setting up your initial respondto mixin
// initial variables set-up
$doc-font-size: 16;
$doc-line-height: 24;
// media query mixin (min-width only)
#mixin breakpoint($point) {
#media (min-width: $point / $doc-font-size +em) { #content; }
}
this will create a min-width media query and output your px value ($point) as an em value.
From this you'd need to create this mixin
#mixin rwdIE($name, $wrapper-class, $IE: true) {
#if $IE == true {
.lt-ie9 .#{$wrapper-class} {
#content;
}
.#{$wrapper-class} {
#include breakpoint($name) {
#content;
}
}
}
#else if $IE == false {
.#{$wrapper-class} {
#include breakpoint($name) {
#content;
}
}
}
}
Here if you pass a piece of Sass(SCSS) like this
#include rwdIE(456, test) {
background-color: #d13400;
}
it will return this code
.lt-ie9 .test {
background-color: #d13400;
}
#media (min-width: 28.5em) {
.test {
background-color: #d13400;
}
}
This will give you the you the IE and 'new browser' CSS in one file. If you write -
#include rwdIE(456, test, false) {
background-color: #d13400;
}
You will get -
#media (min-width: 28.5em) {
.test {
background-color: #d13400;
}
}
I hope this helps, I've got this on a codepen here too - http://codepen.io/sturobson/pen/CzGuI
There is a CSS3 Mixin I use that has a variable for IE filters. You could do something similar by having a global variable, $forIE or something, wrap the media query mixin within an if and then generate the stylesheet with or w/o the queries.
#if $forIE == 0 {
// Media Query Mixin
}
Or use the #if to import a 3rd scss (_forIE.scss?) that will override things with your IE specific styles.