Categories
Apps & scripts CSS WG Original

Conical gradients, today!

Screen Shot 2015-06-18 at 16.26.40It’s no secret that I like conical gradients. In as early as 2011, I wrote a draft for conical-gradient() in CSS, that Tab later said helped him when he added them in CSS Image Values Level 4 in 2012. However, almost three years later, no progress has been made in implementing them. Sure, the spec is still relatively incomplete, but that’s not the reason conical gradients have gotten no traction. Far more underspecified features have gotten experimental implementations in the past. The reason conical gradients are still unimplemented, is because very few developers know they exist, so browsers see no demand.

Another reason was that Cairo, the graphics library used in Chrome and Firefox had no way of drawing a conical gradient. However, this changed a while ago, when they supported mesh gradients, of which conical gradients are a mere special case.

Recently, I was giving a talk on creating pie charts with CSS on a few conferences, and yet again, I was reminded of how useful conical gradients can be. While every CSS or SVG solution is several lines of code with varying levels of hackiness, conical gradients can give us a pie chart with a straightforward, DRY, one liner. For example, this is how to create a pie chart that shows 40% in gold and 60% in #f06:

padding: 5em; /* size */
background: conic-gradient(gold 40%, #f06 0);
border-radius: 50%; /* make it round */

Screen Shot 2015-06-18 at 16.23.57
So, I decided to take matters in my own hands. I wrote a polyfill, which I also used in my talk to demonstrate how awesome conical gradients can be and what cool things they can do. Today, during my CSSConf talk, I released it publicly.

In addition, I mention to developers how important speaking up is for getting their favorite features implemented. Browsers prioritize which features to implement based on what developers ask for. It’s a pity that so few of us realize how much of a say we collectively have in this. This is more obvious with Microsoft and their Uservoice forum where developers can vote on which features they want to see worked on, but pretty much every major browser works in a similar way. They monitor what developers request and what other browsers implement, and decide accordingly. The squeaky wheel will get the feature, so if you really want to see something implemented, speak up.

Since “speaking up” can be a bit vague (“speak up where?” I can hear you asking), I also filed bug reports with all major browsers, that you can also find in the polyfill page, so that you can comment or vote on them. That doesn’t mean that speaking up on blogs or social media is not useful though: That’s why browsers have devrel teams. The more noise we collectively make about the features we want, the more likely it is to be heard. However, the odds are higher if we all channel our voices to the venues browser developers follow and our voice is stronger and louder if we concentrate it in the same places instead of having many separate voices all over the place.

Also, I’m using the term “noise” here a bit figuratively. While it’s valuable to make it clear that we are interested in a certain feature, it’s even more useful to say why. Providing use cases will not only grab browsers’ attention more, but it will also convince other developers as well.

So go ahead, play with conic gradients, and if you agree with me that they are fucking awesome and we need them natively on the Web, make noise.

conic-gradient() polyfill

Categories
Apps & scripts

Awesomplete: 2KB autocomplete with zero dependencies

awesompleteSorry for the lack of posts for the past 7 (!) months, I’ve been super busy working on my book, which up to a certain point, I couldn’t even imagine finishing, but I’m finally there! I’ve basically tried to cram all the CSS wisdom I’ve accumulated over the years in it 😛 (which is partly why it took so long, I kept remembering more things that just *had* to be in it. Its page count on the O’Reilly website had to be updated 3 times, from 250 to 300 to 350 and it looks like the final is gonna be closer to 400 pages) and it’s gonna be super awesome (preorder here!) 😀 . I have been posting a few CSS tricks now and then on my twitter account, but haven’t found any time to write a proper blog post.

Anyhow, despite being super busy with MIT (which btw is amazing, challenging in a good way, and full of fantastic people. So glad to be here!) and the book, I recently needed an autocomplete widget for something. Surprisingly, I don’t think I ever had needed to choose one in the past. I’ve worked with apps that had it, but in those cases it was already there.

At first, I didn’t fret. Finally, a chance to use the HTML5 <datalist>, so exciting! However, the more I played with it, the more my excitement was dying a slow death, taking my open web standards dreams and hopes along with it. Not only it’s incredibly inconsistent across browsers (e.g. Chrome matches only from the start, Firefox anywhere!), it’s also not hackable or customizable in any way. Not even if I got my hands dirty and used proprietary CSS, I still couldn’t do anything as simple as changing how the matching happens, styling the dropdown or highlighting the matching text!

So, with a heavy heart, I decided to use a script. However, when I looked into it, everything seemed super bloated for my needs and anything with half decent usability required jQuery, which results in even more bloat.

So, I did what every crazy person with a severe case of NIH Syndrome would: I wrote one. It was super fun, and I don’t regret it, although now I’m even more pressed for time to meet my real deadlines. I wrote it primarily for myself, so even if nobody else uses it, ho hum, it was more fun than alternative ways to take a break. However, it’s my duty to put it on Github, in case someone else wants it and in case the community wants to take it into its loving, caring hands and pull request the hell out of it.

To be honest, I think it’s both pretty and pretty useful and even though it won’t suit complex needs out of the box, it’s pretty hackable/extensible. I even wrote quite a bit of documentation at some point this week when I was too sleepy to work and not sufficiently sleepy to sleep — because apparently that’s what was missing from my life: even more technical writing.

I saved the best for last: It’s so lightweight you might end up chasing it around if there’s a lot of wind when you download it. It’s currently a little under 1.5KB minified & gzipped (the website says 2KB because it will probably grow with commits and I don’t want to have to remember to update it all the time), with zero dependencies! 😀

And it’s even been verified to work in IE9 (sorta), IE10+, Chrome, Firefox, Safari 5+, Mobile Safari!

’Nuff said. Get it now!

PS: If you’re about to leave a comment on how it’s not called “autocomplete”, but “typeahead”, please go choke on a bucket of cocks instead. 😛

Categories
Original Tips

Dynamically generated SVG through SASS + A 3D animated RGB cube!

Screenshot of the cubeToday, I was giving the opening keynote at Codemania in Auckland, New Zealand. It was a talk about color from a math/dev perspective. It went quite well, despite my complete lack of sleep. I mean that quite literally: I hadn’t slept all night. No, it wasn’t the jetlag or the nervousness that kept me up. It was my late minute decision to replace the static, low-res image of an RGB cube I was using until then with a 3D cube generated with CSS and animated with CSS animations. Next thing I knew, it was light outside and I had to start getting ready. However, I don’t regret literally losing sleep to make a slide that is only shown for 20 seconds at most. Not only it was super fun to develop, but also yielded a few things that I thought were interesting enough to blog about.

The most challenging part wasn’t actually the 3D cube. This has been done tons of times before, it was probably the most common demo for CSS 3D transforms a couple of years ago. The only part of this that could be of interest is that mine only used 2 elements for the cube. This is a dabblet of the cube, without any RGB gradients on it:

The challenging part was creating the gradients for the 6 sides. These are not plain gradients, as you can see below:

RGB cube sidesThese are basically two linear gradients from left to right, with the topmost one being masked with a gradient from top to bottom. You can use CSS Masking to achieve this (for Chrome/Safari) and SVG Masks for Firefox, but this masks the whole element, which would hide the pseudo-elements needed for the sides. What I needed was masks applied to backgrounds only, not the whole element.

It seemed obvious that the best idea would be to use SVG background images. For example, here is the SVG background needed for the top left one:

<svg xmlns="http://www.w3.org/2000/svg" width="200px" height="200px">

<linearGradient id="yellow-white" x1="0" x2="0" y1="0" y2="1">
	<stop stop-color="yellow" />
	<stop offset="1" stop-color="white" />
</linearGradient>
<linearGradient id="magenta-red" x1="0" x2="0" y1="0" y2="1">
	<stop stop-color="red" />
	<stop offset="1" stop-color="magenta" />
</linearGradient>
<linearGradient id="gradient" x1="0" x2="1" y1="0" y2="0">
	<stop stop-color="white" />
	<stop offset="1" stop-color="black" />
</linearGradient>
<mask id="gradient-mask">
	<rect width="100%" height="100%" fill="url(#gradient)"/>
</mask>

<rect width="100%" height="100%" fill="url(#yellow-white)"/>
<rect width="100%" height="100%" fill="url(#magenta-red)" mask="url(#gradient-mask)"/>

</svg>

However, I didn’t want to have 6 separate SVG files, especially with this kind of repetition (cross-linking to reuse gradients and masks across different files is still fairly buggy in certain browsers). I wanted to be able to edit this straight from my CSS. And then it hit me: I was using SASS already. I could code SASS functions that generate SVG data URIs!

Here’s the set of SVG generating SASS functions I ended up writing:

@function inline-svg($content, $width: $side, $height: $side) {
	@return url('data:image/svg+xml,#{$content}');
}

@function svg-rect($fill, $width: '100%', $height: $width, $x: '0', $y: '0') {
	@return unquote('');
}

@function svg-gradient($id, $color1, $color2, $x1: 0, $x2: 0, $y1: 0, $y2: 1) {
	@return unquote('

	');
}

@function svg-mask($id, $content) {
	@return unquote('#{$content}');
}

And then I was able to generate each RGB plane with another function that made use of them:

@function rgb-plane($c1, $c2, $c3, $c4) {
	@return inline-svg(
		svg-gradient('top', $c1, $c2) +
		svg-gradient('bottom', $c3, $c4) +
		svg-gradient('gradient', white, black, 0, 1, 0, 0) +
		svg-mask('gradient-mask', svg-rect('url(%23gradient)')) +
		svg-rect('url(%23bottom)') +
		svg-rect('url(%23top)" mask="url(%23gradient-mask)')
	);
}

/* ... */

.cube {
	background: rgb-plane(blue, black, aqua, lime);

	&::before {
		background: rgb-plane(blue, fuchsia, aqua, white);
	}

	&::after {
		background: rgb-plane(fuchsia, red, blue, black);
	}
}

.cube .sides {
	background: rgb-plane(yellow, lime, red, black);

	&::before {
		background: rgb-plane(yellow, white, red, fuchsia);
	}

	&::after {
		background: rgb-plane(white, aqua, yellow, lime);
	}
}

However, the same functions can be used for all sorts of SVG backgrounds and it’s very easy to add a new one. E.g. to make polygons:

@function svg-polygon($fill, $points) {
	@return unquote('');
}

@function svg-circle($fill, $r: '50%', $cx: '50%', $cy: '50%') {
	@return unquote('');
}

You can see the whole SCSS file here and its CSS output here.

Warning: Keep in mind that IE9 and some older versions of other browsers have issues with unencoded SVG data URIs. Also, you still need to escape hashes (%23 instead of #), otherwise Firefox fails.

Categories
Apps & scripts Original

Introducing Whathecolor: A color game for web developers!

I’ve been interested in digital color for a long time, and this year I decided to risk giving a technical talk about color some of the conferences I’m speaking at. “Why is that risky?” you might ask. Well, it might end up being really interesting, or it may end up alienating both designers because it’s too technical and developers because it’s about a “designery” topic.

In preparation for this talk, I decided to make a simple game to see how well I and other web developers understand color, and especially CSS notations of color. Meet Whathecolor!

The idea is simple: You are presented with a color and you try to type in a CSS color that matches it. It could be anything, from hsl() or rgb() to even named colors (although that would be stupid). It would be interesting to see what averages people get by trying hsl() vs rgb() and whether the former is as easier for web developers as we think. Feel free to post your results here or on twitter! Perhaps in the future, something like this could be used by the CSS WG to test the usability of color notations we’re thinking of adding to CSS instead of speculating about it.

Disclaimer: This is a quick hack. Please don’t complain that it doesn’t look great on your phone and stuff like that.

Also, yes, if you want to cheat, it’s super easy, but I have no idea why somebody would cheat on something like this.

Play

Color proximity

A challenging part in developing this was calculating the proximity of two colors to show the user how close they are getting. My first thought was to use the Euclidean distance of the two colors in the RGB cube and divide it by the maximum distance the color could have from any other RGB color. However, this proved out to be inaccurate in many cases, probably due to the lack of perceptual uniformity in RGB. As an example, try #f0f and #ff80ff. Although they are quite similar visually, the reported proximity was around 66% (1 – 128/382).

So I researched  existing algorithms to get the proximity of two colors. Like most things color-related, it looks like Color Difference is not quite as simple as I thought, and is considered a topic of interest in Color Science. However, converting to L*a*b* and using the CIE94 and CIEDE2000 formulas seemed a bit of an overkill for this and I wasn’t terribly impressed with the CIE76 formula after trying the results out online for some sample pairs (e.g. it gives ~60% for the aforementioned pair, which is even lower than what I got with my naïve RGB method!).

So I experimented a bit and ended up using an average of my original idea and a sum of the HSL differences (divided by the max differences), which seems to work relatively ok.  There are still cases where it’s off, but ho hum. After all, the proximity is mainly useful when you get close enough to the color (>90%), as until then you tend to play it by eye. Any improvements on the algorithm used are welcome. Or if enough people think it’s not working very well, I’ll bite the bullet and end up using DeltaE.

Other notes

  • You do not need a proximity of 100% to win, since rounding errors might prevent you from matching the exact color if you’re using HSL. Also, because matching the exact same color isn’t really important, as long as you get close enough that any difference is imperceptible.
  • I wrote a Color “class” for this, which you can find in color.js. Like most of my open source stuff, it’s MIT licensed. Maybe it could be useful in some other color-related project, who knows.
  • My original idea was to have “levels”, where the color would get increasingly more difficult to get. For example, in the first level, you’d only have to guess simple colors whose RGB coordinates were either 0, 128 or 255. So, my Color.random() method accepts an entropy parameter, for that level. However, when I tested the game with truly random colors (any integer from 0 to 255), it turned out it wasn’t really that hard (it took me about a minute to guess each color), so I ditched the idea of levels early on. The code is still there though.
  • An idea about making it harder in the future would be to introduce semi-transparent (RGBA/HSLA) colors. That would be fun :evil_grin:

ScreenshotPS: The times in this screenshot aren’t real, I wanted to take one quickly, so I used the dev tools.

 

Categories
Apps & scripts Original

Meet dpi.lv: More than you probably wanted to know about screen DPI


Screen Shot 2013-06-10 at 13.41.39

Yesterday (Sunday) I was on a 9.5 hour flight from Canada with no inflight entertainment (well, thanks Air Canada), so I did what every bored human being would do instead of watching movies: I decided to code an app! And out of the infinite set of possible apps somebody can make, I decided to make an app to calculate screen DPI/PPI.

You might be wondering if I’m still (?) sane, but you might be surprised to hear I found myself calculating screen PPIs quite frequently and wanted to save myself the hassle of doing the math every time. I’m a curious person and I wanted to know, even about products I would never buy and even when it wasn’t listed in the tech specs. Yes, my hobbies are somewhat weird. 😮

I first thought about doing such an app a while ago, but never found the time to code it. The last time I had thought about it was a few days ago at the SF Apple Store with a friend. We were looking at the 27″ Apple Thunderbolt displays in awe and thought they must have huge pixel density. After a few calculations in the console (which ironically produced a result faster than the Apple guy my friend asked), it turned out it was only …102. “I need to code an app to make this sort of calculation easy! People are being misled by marketing!” I thought.

Fast forward to my flight. You didn’t expect my laptop battery to last for 9.5 hours, right? Yeah, MacBook Air batteries are good, but not *that* good. Of course it eventually died so I had to find other ways to pass my time (I ended up sleeping — or trying to). However, by the time it died, I had gone over the threshold of being able to give it up, so I spent the rest of the day finishing it, despite my obvious jetlag and sleepiness. I was in the zone — You don’t just go sleeping when you’re in the zone, right?

Besides the DPI/PPI calculator, I added a few other fun things too:

  • A list of devices with pre-calculated data (stored in a separate JSON file, which makes it easy to update — *hint, hint*)
  • Wrote a few FAQ items about DPI/PPI.
  • Like many of my apps, it supports link sharing through URL hashes (for examples, check the screens section).
  • I even bought a proper domain for it (dpi.lv) and drew a logo! The logo took hours by itself. Not just to draw it, but to simplify Illustrator’s ugly, repetitive SVG output (which is still better than what most other tools spit out). Hand-simplifying SVG is a meditative experience that I thoroughly enjoy, to the bewilderment of everyone who read my tweet about it. Just for the lulz, here’s the before and the 66% smaller after (the small design tweaks were intentional)
  • The screen that displays the result resizes to reflect the aspect ratio of the resolution you’ve selected. It even animates to it, with CSS transitions! Oh, and it also uses FlexBox to center the text vertically.

Enjoy!

Of course it’s open source (under an MIT license, as usual), and you can fork it on Github, as usual. The JS is a bit of a mess, but I’m too tired to refactor it now. Same goes for the lack of favicon and tagline. Oh well. I still like it. 🙂

Important: If you are on a display with multiple dots per pixel (e.g. Retina), the resolution (pixel width × pixel height) it tries to guess will be incorrect, so you’ll have to actually input the right one. The default resolution in there is just a hint, it doesn’t mean it’s “broken” if it doesn’t guess right, they’re editable fields. That said, it would be nice to guess right in those cases too, and I will look into it.

Categories
Apps & scripts Original

Preview corner-shape, before implementations!

As an editor of the Backgrounds & Borders Level 4 spec, I am naturally a bit more interested in the cool features it will bring, once implementations start (it’s currently too early for that). One of the coolest features in it is corner-shape. While in Backgrounds & Borders 3, border-radius was only used for rounded (actually, elliptical) corners, with the help of corner-shape, it will be able to do so much more! Beveled corners, scoop-style corners (informally known as “negative border-radius”), even rectangular notches.

Unfortunately, until it’s implemented in browsers, it’s hard to play with it. Or, is it? I spent the weekend creating an app in which you can enter values for corner-shape, border-radius, width, and height, and see the result, simulated through SVG, as well as the fallback in browsers that don’t support border-corner-radius (which is currently all browsers).

corner-shape preview

Obviously, it’s not a full preview, since you can only play with a limited subset of CSS properties, but it should be good for seeing the kinds of shapes that will be possible.You could also copy the generated SVG from the Developer tools of your browser, and use it as a background in any website!

Use it here: corner-shape preview

Tested to work in at least Chrome, IE9, Firefox, Safari and theoretically, should work in any SVG-enabled browser.

Enjoy! Hope you like it.

Important: Please note that corner-shape is still at a very early stage and might completely change before implementations. You can also help to make it better: Play with it and comment on what you think about its naming and functionality!

Categories
Original Tips

Easily center text vertically, with SVG!

These days, we have a number of different ways to vertically align text in a container of variable dimensions:

  • Table display modes
  • Flexbox
  • inline-block hacks
  • Wrapping the text in an extra element and absolutely positioning it
  • …and probably many others I’m forgetting

However, often comes a time when neither is suitable, so here I am, adding yet another option to the list. Of course, it comes with its own set of drawbacks, but there are cases where it might be better than the existing solutions.

Categories
Original

iOS 6 switch style checkboxes with pure CSS

I recently found myself looking at the Tools switch in Espresso:

Not because I was going to use it (I rarely do), but because I started wondering what would be the best way to replicate this effect in CSS. I set on to create something that adhered to the following rules:

  1. It should be keyboard accessible
  2. It should work in as many browsers as possible and degrade gracefully to a plain checkbox in the rest
  3. It shouldn’t depend on pseudo-elements in replaced elements (such as checkboxes), since that’s non-standard so not very dependable
  4. It shouldn’t require any extra HTML elements
  5. It shouldn’t use JS, unless perhaps to generate HTML that could be written by hand if the author wishes to do so.

Why you may ask? Some of them are good practices in general, and the rest make it easier to reuse the component (and they made it more challenging too!).

Categories
Apps & scripts

Easy color contrast ratios

I was always interested in accessibility, but I never had to comply with any guidelines before. At W3C, accessibility is considered very important, so everything we make needs to pass WCAG 2.0 AA level. Therefore, I found myself calculating color contrast ratios very frequently. It was a very enlightening experience. I used to think that WCAG-mandated contrast ratios were too restrictive and basically tried to force you to use black and white, a sentiment shared by many designers I’ve spoken to. Surprisingly, in practice, I found that in most cases they are very reasonable: When a color combination doesn’t pass WCAG, it usually *is* hard to read. After all, the possible range for a contrast ratio is 1-21 but only ratios lower than 3 don’t pass WCAG AA (4.5 if you have smaller, non-bold text). So, effectively 90% of combinations will pass (82.5% for smaller, non-bold text).

There are plenty of tools out there for this. However, I found that my workflow for checking a contrast ratio with them was far from ideal. I had to convert my CSS colors to hex notation (which I don’t often use myself anymore), check the contrast ratio, then adjust the colors as necessary, covert again etc. In addition, I had to adjust the lightness of the colors with a blindfold, without being able to see the difference my adjustments would make to the contrast ratio. When using semi-transparent colors, it was even worse: Since WCAG only describes an algorithm for opaque colors, all contrast tools only expect that. So, I had to calculate the resulting opaque colors after alpha blending had taken place. After doing that for a few days, I got so fed up that I decided to make my own tool.

In addition, I discovered that there was no documented way of calculating the contrast ratio range that can be produced with a semi-transparent background, so I came up with an algorithm (after many successive failures to find the range intuitively), published it in the w3c-wai-ig mailing list and used the algorithm in my app, effectively making it the first one that can accept semi-transparent colors. If your math is less rusty than mine, I’d appreciate any feedback on my reasoning there.

Below is a list of features that make this tool unique for calculating color contrast ratios:

  • Accepts any CSS color the browser does, not just hex colors. To do this, it defers parsing of the color to the browser, and queries the computed style, which is always rgb() or rgba() with 0-255 ranges which be parsed much more easily than the multitude of different formats than modern browsers accept (and the even more that are coming in the future).
  • Updates as you type, when what you’ve typed can be parsed as a valid CSS color.
  • Accepts semi transparent colors. For semi-transparent backgrounds, the contrast ratio is presented with an error margin, since it can vary depending on the backdrop. In that case, the result circle will not have a solid background, but a visualization of the different possible results and their likelihood (see screenshot).
  • You can share your results by sharing the URL. The URL hashes have a reasonable structure of the form #foreground-on-background, e.g. #black-on-yellow so you can even adjust the URL as a form of input.
  • You can adjust the color by incrementing or decrementing its components with the keyboard arrow keys until you get the contrast right. This is achieved by including my Incrementable library.

Browser support is IE10 and modern versions of Firefox, Safari, Chrome, Opera. Basic support for IE9. No responsive version yet, sorry (but you can always send pull requests!)

Save the link: leaverou.github.com/contrast-ratio

Categories
Apps & scripts Original

Introducing Prism: An awesome new syntax highlighter

For the past three weeks, on and off, I’ve been working on releasing Dabblet’s syntax highlighter as standalone, since many people had requested it. Zachary Forrest  suggested the name “Prism” and I liked it so much I decided to go with it, even though there is an abandoned Mozilla project with the same name. I ended up refactoring and extending it so much that I will need to backport it to Dabblet one of these days! This doesn’t mean I bloated it, the core is still a tiny 1.5KB minified & gzipped. It just means it’s more awesome. 🙂

Seriously? The world needs another syntax highlighter?

In certain ways, Prism is better than any other syntax highlighter I’ve seen: