I want to make a function/mixin that will make a color darker if it is already dark but lighter when it is light (normalize/extremeize?)
Is it possible to do this by passing a property name (color, background-color, border-right-color, etc)?
.normalize(#color, #amount, #prop: "color") when (lightness(#color) >= 50%)
{
#prop:lighten(#color, #amount);
}
.normalize(#color, #amount, #prop: "color") when (lightness(#color) < 50%)
{
#prop:darken(#color, #amount);
}
This is currently a feature request on less.js github. So look out for it in less.js 1.4.. until then you can hack it like so...
.mixin(#prop, #value) {
Ignore: ~"a;#{prop}:#{value}";
}
Not very nice and you get an extra property but its the only way at the moment.
Guarded Mixins should be what you are looking for, however you can not use variables to define properties, only their values. So you can do it like this:
.normalize(#color, #amount) when (lightness(#color) >= 50%)
{
color:lighten(#color, #amount);
}
.normalize(#color, #amount) when (lightness(#color) < 50%)
{
color:darken(#color, #amount);
}
So this:
.class1 {
.normalize(#ddd, 10%);
}
Will output this:
.class1 {
color: #f7f7f7;
}
But you can not actually pass a property name as a variable. This is a limitation of LESS unfortunately, and while I've seen ways around it for things like margin direction, there is not a way to just pass any ol' property using a variable.
In the corresponding issue on Less' GitHub there is a workaround suggested by cloudhaed:
.blah () { color: black } // All blahs
.blah(right) { padding-right: 20px } // Right blahs
.blah(left) { padding-left: 20px } // Left blahs
#side: left;
.class { .blah(#side) }
Output
.class { color: black; padding-left: 20px;}
Maybe this will do?
This feature was added since v1.6.0:
#property: color;
.widget {
#{property}: #0ee;
background-#{property}: #999;
}
Compiles to:
.widget {
color: #0ee;
background-color: #999;
}
See http://lesscss.org/features/#variables-feature-properties
Related
Consider the following Less code:
.a {
button,
input[type='button'],
input[type='submit'],
input[type='reset'] {
background: red;
}
}
.b {
button,
input[type='button'],
input[type='submit'],
input[type='reset'] {
background: blue;
}
}
What I'd like to be able to do is define the four possible types of buttons in a reusable way. I used to be able to do this easily in SASS, but have switched to Less in order to use Semantic UI. I can't find a syntax to do this in Less - is it possible?
Okay, I have a solution to this now, derived from this post:
#all-buttons: {
button,
input[type='button'],
input[type='reset'],
input[type='submit'] {
.get-props()
}
};
.set-props(#selectors; #rules; #extension: ~'') {
#selectors();
.get-props() {
&#{extension} { #rules(); }
}
}
.all-buttons(#rules; #extension: ~'') {
.set-props(#all-buttons; #rules; #extension);
}
.a {
.all-buttons({
background: red;
});
}
.b {
.all-buttons({
background: blue;
});
}
// Also enables an extension such as a pseudo selector for each button type
.c {
.all-buttons({
background: green;
}, ~':hover');
}
I'm looking for some kind of if-statement to control the background-color of different div elements.
I have tried the below, but it doesn't compile
#debug: true;
header {
background-color: (yellow) when (#debug = true);
#title {
background-color: (orange) when (#debug = true);
}
}
article {
background-color: (red) when (#debug = true);
}
There is a way to use guards for individual (or multiple) attributes.
#debug: true;
header {
/* guard for attribute */
& when (#debug = true) {
background-color: yellow;
}
/* guard for nested class */
#title when (#debug = true) {
background-color: orange;
}
}
/* guard for class */
article when (#debug = true) {
background-color: red;
}
/* and when debug is off: */
article when not (#debug = true) {
background-color: green;
}
...and with Less 1.7; compiles to:
header {
background-color: yellow;
}
header #title {
background-color: orange;
}
article {
background-color: red;
}
LESS has guard expressions for mixins, not individual attributes.
So you'd create a mixin like this:
.debug(#debug) when (#debug = true) {
header {
background-color: yellow;
#title {
background-color: orange;
}
}
article {
background-color: red;
}
}
And turn it on or off by calling .debug(true); or .debug(false) (or not calling it at all).
I stumbled over the same question and I've found a solution.
First make sure you upgrade to LESS 1.6 at least.
You can use npm for that case.
Now you can use the following mixin:
.if (#condition, #property, #value) when (#condition = true){
#{property}: #value;
}
Since LESS 1.6 you are able to pass PropertyNames to Mixins as well. So for example you could just use:
.myHeadline {
.if(#include-lineHeight, line-height, '35px');
}
If #include-lineheight resolves to true LESS will print the line-height: 35px and it will skip the mixin if #include-lineheight is not true.
I wrote a mixin for some syntactic sugar ;)
Maybe someone likes this way of writing if-then-else better than using guards
depends on Less 1.7.0
https://github.com/pixelass/more-or-less/blob/master/less/fn/_if.less
Usage:
.if(isnumber(2), {
.-then(){
log {
isnumber: true;
}
}
.-else(){
log {
isnumber: false;
}
}
});
.if(lightness(#fff) gt (20% * 2), {
.-then(){
log {
is-light: true;
}
}
});
using on example from above
.if(#debug, {
.-then(){
header {
background-color: yellow;
#title {
background-color: orange;
}
}
article {
background-color: red;
}
}
});
I need to generate some CSS with some comments right above the classes and in those comments, I need to evaluate some variables. I've been successful in doing this in Sass but Less doesn't seem to have the same functionality.
Here's what I need:
/**Header*/
.Header {
font-size: 1.5em;
}
Here's my attempt in Sass:
#function str-replace($string, $search, $replace: '') {
$index: str-index($string, $search);
#if $index {
#return str-slice($string, 1, $index - 1) + $replace + str-replace(str-slice($string, $index + str-length($search)), $search, $replace);
}
#return $string;
}
#mixin rte_property($name) {
/**#{$name}*/
.#{str-replace($name, ' ', '')} {
#content;
}
}
#include rte_property(Header) {
font-size: 1.5em;
}
Here's my attempt in Less:
.rte_element (#name, #rules) {
#className: e(replace(#name, " ", ""));
/**#{name}*/
.#{className} {
#rules();
}
}
.rte_element("Header 2", {
font-size: 1.5em;
});
Is it possible for Less to interpolate/evaluate variables in comments? If so, how?
There is no straight-forward (non-hacky) way to achieve this in Less. Less compiler does not evaluate any variable that is present within comments and so it would continue to be printed as #{var} instead of the evaluated value.
However, that doesn't mean there is no way at all. There is a way of achieving something close. That would be to put the entire comment text into a temporary variable and print it before the selector using selector interpolation technique.
The comment would not cause any impact to how the compiled CSS works (because the UA will just ignore the comments, refer the snippet at the end - it uses the compiled CSS produced by this code) but it doesn't have a line-break.
Note: I would definitely not recommend implementing such hacky solutions. I have given it here just to show that it can be done in a different way.
Less Code:
.rte_element(#name, #rules) {
#className: e(replace(#name, " ", ""));
#comment: ~"/* #{name} */"; /* store the comment structure as a variable */
#{comment} .#{className} { /* print it before the selector */
#rules();
}
}
.rte_element("Header 2", {
font-size: 1.5em;
color: red;
});
.rte_element("Header 3", {
font-size: 1.75em;
color: blue;
});
Demo with compiled CSS:
/* Header 2 */ .Header2 {
font-size: 1.5em;
color: red;
}
/* Header 3 */ .Header3 {
font-size: 1.75em;
color: blue;
}
<div class="Header2">Header 2 text</div>
<div class="Header3">Header 3 text</div>
Code for a line break after comment:
This is even more hacky but it seems to work in the latest compiler.
.rte_element(#name, #rules) {
#className: e(replace(#name, " ", ""));
#comment: ~"/* #{name} */
" ; /* note how there is a line break inside the quotes */
#{comment} .#{className} {
#rules();
}
}
I'm looking for some kind of if-statement to control the background-color of different div elements.
I have tried the below, but it doesn't compile
#debug: true;
header {
background-color: (yellow) when (#debug = true);
#title {
background-color: (orange) when (#debug = true);
}
}
article {
background-color: (red) when (#debug = true);
}
There is a way to use guards for individual (or multiple) attributes.
#debug: true;
header {
/* guard for attribute */
& when (#debug = true) {
background-color: yellow;
}
/* guard for nested class */
#title when (#debug = true) {
background-color: orange;
}
}
/* guard for class */
article when (#debug = true) {
background-color: red;
}
/* and when debug is off: */
article when not (#debug = true) {
background-color: green;
}
...and with Less 1.7; compiles to:
header {
background-color: yellow;
}
header #title {
background-color: orange;
}
article {
background-color: red;
}
LESS has guard expressions for mixins, not individual attributes.
So you'd create a mixin like this:
.debug(#debug) when (#debug = true) {
header {
background-color: yellow;
#title {
background-color: orange;
}
}
article {
background-color: red;
}
}
And turn it on or off by calling .debug(true); or .debug(false) (or not calling it at all).
I stumbled over the same question and I've found a solution.
First make sure you upgrade to LESS 1.6 at least.
You can use npm for that case.
Now you can use the following mixin:
.if (#condition, #property, #value) when (#condition = true){
#{property}: #value;
}
Since LESS 1.6 you are able to pass PropertyNames to Mixins as well. So for example you could just use:
.myHeadline {
.if(#include-lineHeight, line-height, '35px');
}
If #include-lineheight resolves to true LESS will print the line-height: 35px and it will skip the mixin if #include-lineheight is not true.
I wrote a mixin for some syntactic sugar ;)
Maybe someone likes this way of writing if-then-else better than using guards
depends on Less 1.7.0
https://github.com/pixelass/more-or-less/blob/master/less/fn/_if.less
Usage:
.if(isnumber(2), {
.-then(){
log {
isnumber: true;
}
}
.-else(){
log {
isnumber: false;
}
}
});
.if(lightness(#fff) gt (20% * 2), {
.-then(){
log {
is-light: true;
}
}
});
using on example from above
.if(#debug, {
.-then(){
header {
background-color: yellow;
#title {
background-color: orange;
}
}
article {
background-color: red;
}
}
});
how can i hide empty area if i has empty content of tab?
The empty area is the result of the default CSS that the Yii CTabView uses. Specifically, this CSS from web/js/source/jquery.yiitab.js in the Yii sources:
.yiiTab div.view
{
border-left: 1px solid #4F81BD;
border-right: 1px solid #4F81BD;
border-bottom: 1px solid #4F81BD;
padding: 8px;
margin: 0;
}
You can see this for yourself if you do not include any CSS at all, in which case the tabs will be displayed without any styles:
$this->widget('CTabView', array('tabs'=> $tabs, 'cssFile' => false));
The best solution would be to derive your own widget CustomTabView from CTabView, and override the renderBody method like this:
protected function renderBody()
{
foreach($this->tabs as $id=>$tab)
{
$inactive=$id!==$this->activeTab?' style="display:none"' : '';
$empty = $this->isEmptyTab($tab) ? ' empty' : '';
echo "<div class=\"view{$empty}\" id=\"{$id}\"{$inactive}>\n";
if(isset($tab['content']))
echo $tab['content'];
else if(isset($tab['view']))
{
if(isset($tab['data']))
{
if(is_array($this->viewData))
$data=array_merge($this->viewData, $tab['data']);
else
$data=$tab['data'];
}
else
$data=$this->viewData;
$this->getController()->renderPartial($tab['view'], $data);
}
echo "</div><!-- {$id} -->\n";
}
}
Then you need an isEmptyTab method. This one will work for tabs which have their content set manually by you. If that's not good enough, extend it as you require:
private function isTabEmpty($tab)
{
if(isset($tab['content']) && $tab['content'] == '')
{
return true;
}
return false;
}
Finally, you need some CSS to make your empty tabs appear differently, for example:
.yiiTab div.view.empty
{
border: none;
padding: 0;
margin: 0;
}