My Razor component populates a number of divs to a container.
Is it possible to inherit the table-stripe color and apply it to my divs (odd) rather than overriding it?
Or, if I declared a new CSS class "Div-Stripe-Row".
Is it possible to reference the background-color from Bootstrap's table-striped background-color (use what's already there) rather than declaring a new color (overriding it by just copying what the color is)?
Your question may be a duplicate of this one.
Unless you want to use LESS, I would recommend adding a class to those divs and copy the styles of the Razor component to that class.
Unfortunately, CSS does not provide 'inheritance' in the way that programming languages like C++, C#, or Java do. You can't declare a CSS class and then extend it with another CSS class.
However, you can apply more than a single class to a tag in your markup ... in which case there is a sophisticated set of rules that determine which actual styles will get applied by the browser.
See https://stackoverflow.com/a/1065476/3842598
The accepted answer says:
There are tools like LESS, which allow you to compose CSS at a higher level of abstraction similar to what you describe.
Less calls these "Mixins"
...
See https://stackoverflow.com/a/1065476/3842598
Related
This question likely has no single direct answer, but hopefully will lead to some best practices or common patterns to use when adapting an existing styles framework to new web component development.
For my case, I have a component <custom-avatar>, and it's all set up properly with self-contained styles and functionality, everything is just peachy.
In certain use cases, the application display needs to stack avatars, just one slightly overtop one other at a diagonal, and the pattern I'm following is using a simple component <custom-composite-avatar>. All this does is wrap the slotted content in a <div> with the correct styling class, but key aspect is retaining the composability for flexible re-use, like so:
<custom-composite-avatar>
<custom-avatar title="first"></custom-avatar>
<custom-avatar title="second"></custom-avatar>
</custom-composite-avatar>
The tricky bit lies in the styles, which are imported from a monorepo that provides the same BEM-ish CSS and component CSS modules to other flavors of the component library like React, Vue, etc. I have the avatar and composite-avatar styles imported just fine, but forcing the intended overlap display is defined with the hierarchical selector .my-composite-avatar.my-composite-avatar--medium .my-avatar {}
So with .my-composite-avatar class applied to the div wrapper within <custom-composite-avatar> and the .my-avatar class applied to the wrapper within the <custom-avatar> and it's own Shadow DOM, that parent/child CSS selector is no good.
I doubt there is a silver bullet for this, but this seems like it will be a rather common scenario as more people migrate to Web Components while using existing styling systems. What approach makes the most sense to ensure that the composite component remains composable, and adaptation of existing selectors pain-free (or at least easy to communicate to other devs)? can this be solved with ::host or ::slotted, or will these cases require significant re-work?
Thanks for reading, your ideas are appreciated!
I would advice to become good friends with CSS properties
because they trickle down into shadowDOMs following CSS selectors.
CSS Custom Properties(variables)
and getPropertyValue
and setProperty if you want to be brutal and make Custom Elements change the outside world.
example
I have an <SVG-ICON> element taking configuration from attributes OR CSS properties
with my favorite lines of code:
let val = this.getAttribute(attr)
||
getComputedStyle(this)
.getPropertyValue("--svg-icon-" + attr)
.replace(/"/g, "")
.trim();
Allows for your standard attribute configuration:
<svg-icon name="configuration" fill="grey"></svg-icon>
But more powerful (simplified example):
<style>
body {
--svg-icon-fill: "grey";
}
svg-icon[selected] {
--svg-icon-fill: "green";
}
</style>
<svg-icon name="messages" selected></svg-icon>
<svg-icon name="configuration"></svg-icon>
CSS = Custom String Scripting
It doesn't often happen, but sometimes the simplest code makes me very happy.
There is no Styling restriction!
These 2 lines allow any String you want in CSS properties:
.replace(/"/g, "")
.trim();
Example
<style>
[name*="globe"] {
--svg-icon-tile: "rect:0,0,24,24,0,fill='blue'";
--svg-icon-stroke: white;
}
</style>
<svg-icon name="feather-icons-globe"></svg-icon>
The --svg-icon-tile has nothing to do with CSS, it is read (and parsed) by the <SVG-ICON> connectedCallback() code to generate a SVG background/tile for all icons named globe.
The double-quotes aren't required, but without them your IDE will complain about invalid CSS.
Have fun coding... you will pull some hairs when you start with calc() in your CSS properties...
But you can take 'CSS' to another level.
PS.
And monitor the future of ConstructAble StyleSheets aka ConstructIble StyleSheets aka Constructed Sheets aka AdoptedStyleSheets:
https://developers.google.com/web/updates/2019/02/constructable-stylesheets
https://chromestatus.com/feature/5394843094220800
iconmeister
I'm developing a multi-module application using GWT 2.5.1. I'm not using any GWT theme. I want to customize the style for some of the GWT widgets, for example Button and CheckBox.
I see two solutions:
Write a CSS file loaded in the application (link in the HTML page). The CSS will contain CSS rules using GWT defined names, like .gwt-Button for buttons and .gwt-CheckBox, .gwt-CheckBox-disabled for checkboxes. This solution don't takes the advantage of CSS optimizations made by the GWT compiler.
Use a CssResource and set the style name each time I use a Button or a Checkbox. This solution will take advantage of CSS optimizations but it requires to set the style name every time I create a new Widget.
There are other solutions? Which is the correct one?
You can put those styles in a CssResource as well.
Just put #external on top of those styles in your css file, and you are good to go.
For example:
#external gwt-DatePicker;
.gwt-DatePicker {
...
}
Hope it helps.
Other solution: Button is html element button and Checkbox an html element input[type=checkbox]. So you could set styles on those elements and use css selectors for specific states. i.e. button:disabled. That way you won't have to set style names, or don't have lots of extra style names and use cleaner css.
You could subclass whatever widgets you want to style (e.g. MyButton), and have your subclass either just add a style name to each widget that gets created, or do the styling inline using calls to this.setWidth(), this.getElement().getStyle.setXXX.
Also, what optimizations does the GWT compiler perform on CSS? I know that it will obfuscate style names to avoid collisions, but I'm not sure CSS is even able to be optimized?
I would personally use emanuele's solution, but just to offer an alternative: you can use a widget's getElement() method to access style names directly, so if you really want to, you can override the style names with ones you created. This gets rather difficult, however, with larger widgets and panels that have multiple styles.
I'm using the Notes 9 extension library application layout control and I would like to use CSS to float the place bar actions on the left instead of the right.
Those actions are styled with the lotusBtnContainer class using a float:right property. How do I override that class with my own class that uses a float:left?
I can make the adjustment to the lotusBtnContainer class in firebug but I don't want to touch that class for obvious reasons.
Quick answer: cascading. If your stylesheet is below the stylesheet that defines lotusBtnContainer, then it will override the styles above it. You should be able to add a stylesheet to the page that contains the same definition. One caveat is that you must match the specificity of the lotusBtnContainer definition in the theme stylesheet. If the css definition is td.lotusBtnContainer then in order to override you must also use td.lotusBtnContainer, not just .lotusBtnContainer.
If you need any additional help with this, please add the definition of the lotusBtnContainer from the default css files and I can assist further.
Edit: Additionally, if this doesn't work, adding the class with the style you want like this should override:
.lotusBtnContainer{float:left !important;}
When a JavaScript library creates a <div>, it typically sets a class on the div so that the user of the library can style it him/herself. It's also common, however, for the JS library to want to set some default styles for the <div>.
The most obvious way for the library to do this would be with inline styles:
<div style="application's default styles" class="please-style-me">
...
</div>
However, this will make the application's default styles trump the user's styles. A workaround is to use nested divs:
<div style="application's default styles">
<div class="please-style-me">
...
</div>
</div>
This works great for many styles like 'font' but fails for others like 'position', where the inner div's style will not override the outer div's.
What is the best practice for creating user-stylable elements with defaults in a JavaScript library? I'd prefer not to require users to include a CSS file of defaults (it's nice to keep your library self-contained).
When a JS library has a default set of styles that should be used, but should also be overridden, the JS library should include a separate stylesheet.
JavaScript should avoid adding styles directly as much as possible, and defer all styling to CSS where it's reasonable.
It's common for sets of styles to be toggled on and off. The way to elegantly handle these situations are with CSS classes.
A case where it may not be reasonable to simply use external stylesheets is animation. CSS animations could certainly be used, but for cross-browser support, asynchronous interpolation is used to animate styles from one value to another.
There isn't !notimportant or !unimportant in CSS. And I haven't run into an accepted best practice. It seems like a CSS file is the defacto standard for styles that should be user modifiable.
But if you want to keep things all in one library, I would take your second example, with your application default styles, then append a CSS class to it and prepend something unique to the class name. Then if the implementor wants to override your styles, the implementor could just use !important to override your user styles.
Adding !important to one or two styles in a CSS file shouldn't be a huge deal, but if you're creating a bunch of inline styles, this may not be the best solution.
I have made some templates on wikia.com, which contain only CSS code (key:value;).
My problem is having another template use these style templates in a style attribute tag.
style="{{MyTemplateStyle}}"
This code does not evaluate as expected. The CSS code is outputted before the element and the style attribute is not included inside the element.
Am I trying something not possible for a wiki ?
I merely want to be able to change styling on certain templates in one place, like regular HTML & CSS pages.
CSS styling specified from the style="" attribute always takes priority over any other css, even if you use !important in a CSS specification.
Therefore any edits you make to your CSS on Wikia will not ever override the CSS specified inside an attribute.
Kim, you were right to switch to classes instead of embedding in-line styles via templates.
The very idea of using templates suggest that this was going to be re-used in more than one place, applying styles to a group or, in fact, a class of elements.
This approach is much simpler to read and maintain (as you only have one, central place to edit), and also, if done right, will enable you to seamlessly change the colour scheme via Special:ThemeDesigner.