Whereas You Weren’t Trying, CSS Gradients Obtained Higher

One factor that caught my eye on the checklist of options for Lea Verou’s conic-gradient() polyfill was the final merchandise:

Helps double place syntax (two positions for a similar shade cease, as a shortcut for 2 consecutive shade stops with the identical shade)

Surprisingly, I lately found most individuals aren’t even conscious that double place for gradient stops is one thing that really exists within the spec, so I made a decision to write down about it.

Based on the spec:

Specifying two areas makes it simpler to create solid-color “stripes” in a gradient, with out having to repeat the colour twice.

I utterly agree, this was the very first thing I considered once I turned conscious of this function.

For example we wish to get the next outcome: a gradient with a bunch of equal width vertical stripes (which I picked up from an earlier submit by Chris):

Screenshot. Shows 8 vertical rainbow stripes, from left to right: violet, magenta, red, orange, yellow, yellowish green, teal, blue.Desired gradient outcome.

The hex values are: #5461c8, #c724b1, #e4002b, #ff6900, #f6be00, #97d700, #00ab84 and #00a3e0.

Let’s first see how we would CSS this with out utilizing double cease positions!

We’ve got eight stripes, which makes every of them one-eighth of the gradient width. One eighth of 100% is 12.5%, so we go from one to the following at multiples of this worth.

This implies our linear-gradient() appears as follows:

linear-gradient(90deg,
#5461c8 12.5% /* 1*12.5% */,
#c724b1 zero, #c724b1 25% /* 2*12.5% */,
#e4002b zero, #e4002b 37.5% /* three*12.5% */,
#ff6900 zero, #ff6900 50% /* four*12.5% */,
#f6be00 zero, #f6be00 62.5% /* 5*12.5% */,
#97d700 zero, #97d700 75% /* 6*12.5% */,
#00ab84 zero, #00ab84 87.5% /* 7*12.5% */,
#00a3e0 zero)

Word that we need not repeat cease place % values as a result of, each time a cease place is smaller than a earlier one, we mechanically have a pointy transition. That is why it is at all times protected to make use of zero (which is at all times going to be smaller than any constructive worth) and have #c724b1 25%, #e4002b zero as a substitute of #c724b1 25%, #e4002b 25%, for instance. That is one thing that may make our life simpler sooner or later if, for instance, we determine we wish to add two extra stripes and make the cease positions multiples of 10%.

Not too unhealthy, particularly in comparison with what gradient mills usually spit out. But when we determine a type of stripes within the center would not fairly slot in with the others, then altering it to one thing else means updating in two locations.

Once more, not too unhealthy and nothing we won’t get round with a bit of little bit of assist from a preprocessor:

$c: #5461c8 #c724b1 #e4002b #ff6900 #f6be00 #97d700 #00ab84 #00a3e0;

@perform get-stops($c-list)
$s-list: ();
$n: size($c-list);
$u: 100%/$n;

@for $i from 1 to $n
$s-list: $s-list,
nth($c-list, $i) $i*$u,
nth($c-list, $i + 1) zero

@return $s-list

.strip

This generates the precise CSS gradient we noticed a bit earlier and now we do not have to switch something in two locations anymore.

See the Pen by thebabydino (@thebabydino) on CodePen.

Nonetheless, even when a preprocessor can save us from typing the identical factor twice, it would not remove repetition from the generated code.

And we could not at all times wish to use a preprocessor. Leaving apart the truth that some individuals are cussed or have an irrational worry or hate in direction of preprocessors, it generally feels a bit foolish to make use of a loop.

For instance, once we barely have something to loop over! For example we wish to get a a lot easier background sample, comparable to a diagonal hashes one, which I would think about is a way more frequent use case than an over-the-top rainbow one which’s in all probability not a very good match on most web sites anyway.

Screenshot. Shows a pattern of diagonal light grey hashes on a white background.Screenshot. Shows a pattern of diagonal light grey hashes on a white background.Desired hashes outcome

This requires utilizing repeating-linear-gradient() and this implies a little bit of repetition, even when we do not have the identical lengthy checklist of hex values as we did earlier than:

repeating-linear-gradient(-45deg,
#ccc /* cannot skip this, repeating gradient will not work */,
#ccc 2px,
clear zero,
clear 9px /* cannot skip this both, tells the place gradient repetition begins */)

Right here, we can’t ditch the primary and final stops as a result of these are exactly what point out how the gradient repeats throughout the rectangle outlined by the background-size.

If you wish to perceive why it is higher to make use of repeating-linear-gradient() as a substitute of a plain previous linear-gradient() mixed with the correct background-size with a purpose to create such hashes, try this different article I wrote some time in the past.

That is exactly the place such function involves the rescue — it permits us to keep away from repetition within the ultimate CSS code.

For the rainbow stripes case, our CSS turns into:

linear-gradient(90deg,
#5461c8 12.5%,
#c724b1 zero 25%,
#e4002b zero 37.5%,
#ff6900 zero 50%,
#f6be00 zero 62.5%,
#97d700 zero 75%,
#00ab84 zero 87.5%,
#00a3e0 zero)

And to recreate the hashes, we solely want:

repeating-linear-gradient(-45deg,
#ccc zero 2px,
clear zero 9px)

See the Pen by thebabydino (@thebabydino) on CodePen.

What about assist? Effectively, glad you requested! It truly occurs to be fairly good! It really works in Safari, Chromium browsers (which now consists of Edge as properly!) and Firefox. Pre-Chromium Edge and possibly some cell browsers might nonetheless maintain you again, but when you do not have to fret about offering assist for each browser below the solar or it is nice to offer a fallback, go forward and begin utilizing this!

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