Dynamically change element styles via custom properties? - css

For example, you can change the ink colour in paper-tabs by changing --paper-tab-ink: var(--accent-color);. Is it possible to change the value of the CSS custom properties dynamically similar to how you can toggle a class or change the style in JS?

There are different ways to do this, but a simple answer is to use the Polymer.updateStyles() method after making your class changes.
For example, let's say your styles are:
<style>
.yellow x-example {
--light-primary-color: #fdd85f;
}
.red x-example {
--light-primary-color: red;
}
</style>
and you want to make the component use the styles in the .red class. You simply add it as you normally would in javascript, then be sure to also use this function to actually update it on the page.
<div class="yellow" onclick="this.className='red'; Polymer.updateStyles()">
<x-example></x-example>
</div>

Yes, first get the object of your custom element. Then get the customStyle object. Add a style to that object. And then run element.updateStyles();
t.clickListener= function(e) {
var t = Polymer.dom(e).localTarget; //retarget if needed
t.customStyle['--the-color-etc'] = 'pink';
t.updateStyles(); // mandatory for the CSS variables shim
};
See the docs

Related

How to dynamically generate CSS class and/or set its property

The title is not really a question it is more like an idea, I don't know what approach is best for my situation.
So, the problem. I have some 3rd party component that have some complex structure and styling. Some part of it has some predefined CSS class that I can override with CSS in my surrounding component. Something like this:
my component:
<div class="my-cmp-container">
<some-3rd-party-cmp></some-3rd-party-cmp>
</div>
3rd party component:
<div class="3rd-party-css-class">
...
</div>
For example, 3rd-party-css-class has style background-color: #f00, I can override it with .my-cmp-container .3rd-party-css-class { background-color: #fff; } etc. But. What if I need to set color dynamically, it's stored in a DB for example and I can't predefine each case in my class' CSS. I just have the color in hex.
In theory I can generate unique string to set as CSS class for every instance of some-3rd-party-cmp and somehow generate CSS in my component? I'm lost a little, what is the best approach for this?
Edit: Code sample to illustrate the situation https://stackblitz.com/edit/angular-kxdatq
What you are trying to do is the subject of this open issue about stylesheet binding in Angular. Until that feature is available, you can get what you want with a custom directive. Here is a directive that retrieves the checkbox element generated by ng-zorro-antd and applies two color attributes to it. The two colors are #Input properties and the directive implements OnChanges which allows to react to property binding changes.
#Directive({
selector: "[nz-checkbox][nz-chk-style]"
})
export class CheckBoxStyleDirective implements OnInit, OnChanges {
#Input("nz-chk-bkgnd") chkBkgndColor: string;
#Input("nz-chk-border") chkBorderColor: string;
private checkbox: HTMLElement;
constructor(private renderer: Renderer2, private el: ElementRef) { }
ngOnInit() {
this.checkbox = this.el.nativeElement.querySelector(".ant-checkbox-inner");
this.updateBackgroundColor();
this.updateBorderColor();
}
ngOnChanges(changes: SimpleChanges) {
if (changes.chkBkgndColor) {
this.updateBackgroundColor();
}
if (changes.chkBorderColor) {
this.updateBorderColor();
}
}
updateBackgroundColor() {
if (this.checkbox) {
this.renderer.setStyle(this.checkbox, "background-color", this.chkBkgndColor);
}
}
updateBorderColor() {
if (this.checkbox) {
this.renderer.setStyle(this.checkbox, "border-color", this.chkBorderColor);
}
}
}
Once the directive attribute selector nz-chk-style is applied to the 3rd party element, you can set the checkbox background and border colors with property binding as follows:
<span nz-checkbox nz-chk-style [nz-chk-bkgnd]="bkgndColor" [nz-chk-border]="borderColor" >
See this interactive stackblitz for a demo.
Not sure if you are using Angular but you tagged it, so I guess you are.
If you want to change only the color and nothing more, instead of having a .3rd-party-css-class class, you could just have your with an ng-style like so:
<some-3rd-party-cmp ng-style="{ color: your_color_hex_variable }"></some-3rd-party-cmp>
You can also define a whole object if styles and pass it.
You can also use ng-class and pass one or an array of class names what you want to put additionally on your component:
<some-3rd-party-cmp ng-class="[cls1, cls2, cls3]"></some-3rd-party-cmp>
<some-3rd-party-cmp ng-class="[3rd-party-css-class, someCondition ? 'another-class-name' : '']"></some-3rd-party-cmp>
In the classes you can define the css rules you want to apply and thats it.
With this solutions you can avoid having extra wrapper elements for styling purposes which is a nice thing.

Vuejs: How to bind a variable to global css class?

I would like to bind a variable as it:
<style lang='sass'>
.picker-item.picker-item-selected
background-color: {{ MY_BG_COLOR }}
</style>
this obviously does not work.
For the context I'm using a picker from framework7 which I want to override the background-color depending of user actions.
Then I cannot really use usual ways to bind values for styling
Is there a way to bind a value for global css class?
You can't do that you want directly, but you can Use "inline style":
You must to bind an inline style with a variable
<div id="app">
<div :style="divInline">Hello</div>
</div>
You must create the variable in the data section
data: {
divInline: 'background-color:red;'
}
after that, you can change the inline style through methods.
methods: {
changeColor( color ) {
this.divInline = 'background-color:' + color + ';'
}
}
Example complete

Applying dynamic styling to injected HTML in Angular 2

For an Angular project I'm working on, I'm injecting HTML into a <div> like so:
<div class="myClass" [innerHTML]="htmlToInsert"></div>
The htmlToInsert contains a variety of things, notably <a> tags. Previously we were styling all these tags like so:
.myClass ::ng-deep a {
color: #f00;
text-decoration: none;
}
And this worked fine. But now I need the color of these links to be dynamically generated during component initialization, based on data coming in from elsewhere. All of the dynamic styling I've seen in Angular requires you to apply things directly to the HTML tag, but we don't have them here to work with.
How can I apply dynamic styling to HTML that is also dynamically generated? Can I directly change the CSS class somehow? Would using a pipe be the correct approach here? Is there another method I don't know about? I could maybe refactor code if there is absolutely no other way of doing this.
So if you can't modify the innerHTML you are passing in, you can achieve this functionality with a custom directive. Essentially you would tag your div that contains your innerHTML with a custom directive. That directive then looks for any anchor tags in it and changes the color based on an input.
// component.html
<div anchorColor [color]="dynamicColor" [innerHTML]="htmlToInsert"></div>
// directive.ts
#Directive({selector: '[anchorColor]'})
export class AnchorColorDirective implements OnAfterViewInit {
#Input() color: string;
constructor(private el: ElementRef){
}
// afterViewInit lifecycle hook runs after DOM is rendered
ngAfterViewInit(){
// get anchor element
let anchorEl = this.el.nativeElement.querySelector('a');
// assign color
if(anchorEl){
anchorEl.style.color = this.color;
}
}
}
Here is a working plunkr https://plnkr.co/edit/QSYWSeJaoUflP94Cy4Hm?p=preview

How to customize the Semantic UI buttons(background-color, border-radius and all)

How to customize the Semantic UI buttons(background-color, border-radius and all)
<button class="ui button create-new-menu-btn">Create New Menu</button>
. create-new-menu-btn {
border-radius: 0;
background-color: red;
}
The above code is not working
You need to make your custom properties more specific than the ones semantic is using. How specificity works (simply) is that when there are competing property values on the same element, the one that is more "specific" is chosen.
Read this to know more about CSS specificity: https://developer.mozilla.org/en/docs/Web/CSS/Specificity
For your particular problem:
One way to make your custom CSS more specific is to use an id in the body tag of your page and use the following selector:
Method 1
#bodyid .create-new-menu-btn {
//Properties
}
Another way is to simply add an id to the element you want to select
Method 2
#create-new-menu-btn {
}
Method 1 is preferred when you want to apply the properties on multiple elements (hence the use of a class) (Like multiple comment buttons on a page)
Method 2 is preferred when there is a single element to be selected. (Like a login/signup button in the header)
You can also add semantic ui's classes before your own for specificity.
For example : if your className is .create-new-menu-btn you can add in css or scss before ui.button or any other semantic ui specific clas that you neeed. So in the end, your class definition in css would look like this:
ui.button.create-new-menu-btn {
....
}
If using JSX, you can use inline styling for the targeted elements
Example:
<Button style={{backgroundColor: 'red', borderRadius: 0}}> View Created </Button>
#bodyId .ui.create-new-menu-btn {
border-radius: 0;
background-color: red;
}
It will target all button with ui class.
Hope It will be useful :)
Put .ui.button infront of your class name create-new-btn. It should look like below
.ui.button.create-new-btn {
//Your css code
}
Then in your html/jsx template you can use the class name create-new-btn like below:
<Button class="create-new-btn"/>
or for Jsx
<Button className="create-new-btn"/>

Add custom style property to MXML Custom Component

I have a Custom Component that has a couple of Canvas with some background colors assigned to them. Now i have hard coded the colors, i want to move them to an external css file.
So i would like to have the css declaration like this :
ControlBar
{
dividerRightColor: #ffffff;
dividerLeftColor: #f3f3f3;
}
My question is if i can define custom style names like dividerRightColor and if so, how can i use that value inside my MXML Component? I have seen examples of using them inside Pure AS components.
In CSS:
.dividerRightColor {
background-color: #ffffff;
}
.dividerLeftColor {
background-color: #f3f3f3;
}
In MXML:
<mx:ControlBar>
<mx:Canvas styleName="dividerLeftColor">
…
</mx:Canvas>
<mx:Canvas styleName="dividerRightColor">
…
</mx:Canvas>
</mx:ControlBar>
It sounds to me like you need to create the style in the component; not just send the style values into the component as the other answer.
Read this documentation.
Basically, styles don't get defined the same way that properties get defined. You can set any style name on the component you want. However, the component needs to know what to do w/ the style. To do that you need to override the styleChanged method:
override public function styleChanged(styleProp:String):void {
super.styleChanged(styleProp);
// Check to see if style changed.
if (styleProp=="dividerRightColor")
{
// do stuff to implement the style
dividerRight.setStyle('backgroundColor',getStyle('dividerRightColor'));
}
}
A common approach is to set "styleChanged" properties and invalidate the display list and then make the appropriate style changes in the updateDisplayList() method.
To make the style available in code hinting, you'll need to add metadata, like this:
[Style(name="dividerRightColor")]
This will only be required if you wish to set the style as a property in MXML.

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