technorthodox http://blog.briancavalier.com a bunch of stuff that doesn't really go together posterous.com Fri, 04 Feb 2011 11:33:00 -0800 OOCSS slides and more from the jQuery Pgh meetup http://blog.briancavalier.com/oocss-slides-and-more-from-the-jquery-pgh-mee http://blog.briancavalier.com/oocss-slides-and-more-from-the-jquery-pgh-mee

I hope everyone who attended last night’s jBurgh meetup had as much fun as I did, and enjoyed my talk on OOCSS. I thought it was a great low-key event, and I have to say that the discussion after the presentation and hanging around talking to everyone were the best parts.

My slides are up on slideshare, and if you were at the meetup, I’d really appreciate your taking a minute to rate my talk, and (especially!) leave a comment about how it could be improved.

If you’re interested in getting more background on OOCSS, I encourage you to check out Nicole’s slides and video. I’ve also written a few articles that dig deeper into some of the concepts in last night’s talk, such as OOCSS inheritance, why .css() is bad, and OOCSS Antipatterns:

You can also check out the digital clock demo, including these other versions:

  • Analog – remember this is an antipattern (see above), no matter how cool it seems!
  • JQCon explode – we did this mod live onstage at JQCon
  • Daniel Lamb’s binary clock mod – he points directly to my JS view controller (view source to check it out), and just modded the HTML and CSS. Now that’s separation of concerns FTW.

For more deep diving along with some excellent code examples and comment discussion, I also recommend reading John Hann’s post on OOCSS for Engineers.

At the end of the presentation, I mentioned that I’m working on OOCSS design patterns for web applications. My plan is to post more information soon about the ones mentioned in the slides (with example code), as well as others, so stay tuned.

Thanks to Chris Bannon and Wijmo for organizing and sponsoring, to HackPittsburgh for lending us their space, and to everyone who attended! I had a blast, and I’m already looking forward to the next meetup.

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Fri, 21 Jan 2011 09:39:00 -0800 Simple OOCSS Slideshows http://blog.briancavalier.com/simple-oocss-slideshows http://blog.briancavalier.com/simple-oocss-slideshows

I read this article recently, and decided to solve the problem the author proposes in point #3 using OOCSS techniques.

Here you go: OOCSS Slideshows.

You might be saying, “Good grief, all that CSS is overkill!”, and be tempted to think that just using image.style.display = 'none' is good enough. Try implementing those 3 effects in plain Javascript … you probably wouldn’t get it right—I know I probably wouldn’t.

Or maybe you’re thinking that you’d just use jQuery, Dojo, or your favorite effects library to do it. Putting aside the fact that the original interview question stipulated no libraries, the advantage of an OOCSS approach, as I’ve written about at length before, is separation of concerns, and all its related benefits.

Using an MVC and OOCSS approach puts control of the slideshow transitions into the hands of the designer, and changes to the transitions require zero Javascript changes.

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Tue, 26 Oct 2010 06:46:00 -0700 OOCSS Antipatterns: Analog clock theme using only CSS http://blog.briancavalier.com/oocss-antipatterns-analog-clock-theme-using-o http://blog.briancavalier.com/oocss-antipatterns-analog-clock-theme-using-o

You asked for it, and you got it. Several people asked me after the digital clock demo at jQCon if I thought it was possible to create an analog theme for the clock using only CSS. I had wondered this as well, but came to the conclusion that it was impossible, given the current HTML structure. So, that’s the answer I gave at the conference.

The very next day, I thought of a way to do it, so here’s an analog theme (source on github) for the digital clock done entirely in CSS.

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/* Hide the first hour, minute, and second digits */
.analog .digit:first-child, .analog .sep + .minute, .analog .minute + .second, .analog .controls .hours {
display: none;
}

/* ... */

/* Rotate the hour hand based on the _two adjacent_ hour digits */
.analog .hour.d0 + .d1, .analog .hour.d1 + .d3 {-webkit-transform: rotate(30deg); -moz-transform: rotate(30deg);}

First, note a couple things:

  1. The first hour, minute, and second digits are hidden.
  2. The second hour, minute, and second digits have been styled to look like analog clock hands—i.e. long thin rectangles, and have been anchored at the center of the analog clock face.

The key is the use (in fact, abuse, read on!) of the immediate sibling selector to rotate the clock hands to the correct position, using CSS3 transforms. For example, the line above says when the first hour digit is a “0”, and the second hour digit is also a “1” rotate the second digit (remember, it’s been styled to look like an analog clock hand) by 30°. Each hour represents 30° (360 / 12 = 30), so looking at the rest of the hour selectors, you can see how it works.

Similarly, the minutes and seconds are rotated using the immediate sibling selector. The only difference is the degrees, since 360 / 60 = 6° per minute/second.

Ok, neat, it works, but …

How not to build an analog clock

At this point, you’re probably saying to yourself (and if you’re not, you should be) “This is a terrible way to build an analog clock”. You are absolutely right. There are many problems with this, and I’d even go so far as to call the whole thing an antipattern.

From the HTML element hierarchy, to the CSS classnames, to the time computations, most everything tailored to represent an LED-based digital clock.

However, the point of this little exercise was not to find the best way to engineer an analog clock. The point was to answer the question “could it be done?”. But maybe we can learn something about OOCSS anyway.

There is something to be learned here

As the saying goes, “when all you have is a hammer, everything looks like a nail”, and in this case of trying to use only OOCSS to transform the digital clock into analog, there’s certainly some overly-ambitious hammering going on.

If the HTML is poorly-suited to the task at hand, trying to apply OOCSS on top of it will probably just make things worse. In fact, in this example, the HTML and CSS are fighting each other rather than working together.

OOCSS is not just about CSS, it’s about identifying objects in the view first (as John said in our presentation, “ignore the HTML!”), and then structuring HTML and CSS around the containers, content, identity, and states of those objects.

The fact is that the objects in this clock are LED digits, not analog clock hands, and some mildly clever CSS doesn’t change that. Conversely, this bastardization means that the hands of the analog clock have the classes “display-area” and “digit”, as well as “d0” – “d9”, none of which seem like logical choices for the hands of an analog clock!

Antipattern: In any reasonably complex system, writing HTML and CSS first is an antipattern.

What to do?: Break out the wireframes, gather around the whiteboard, and start identifying objects! List their states. Talk about ways to translate them into well-structured HTML containers and content.

One of the results of this object/HTML/CSS mismatch is state explosion, aka combinatorial explosion. There are 72 CSS rules needed just to rotate the clock hands, whereas there are only 10 rules for the original digital clock LED digits. That certainly qualifies as state explosion, and just looking at the analog rules should give you an uneasy feeling that something is wrong.

In fact, modeling any analog clock, not just this bad example of an analog clock, as discrete OOCSS states seems wrong. Consider also the progress bar example John gave during our talk. Progress bars, in most cases, represent a continuous function rather than a discrete function, and therefore can require an infinite number of states to model their possible values—e.g. 30%, 30.1%, 30.15%, and so on.

Antipattern: Trying to model continuous values with OOCSS state is an antipattern.

What to do?: Use a mechanism better suited to continuous values/functions, such as a vector library, or yes, even direct (but well abstracted!) style manipulation.

One other thing that should be bothering you about this analog clock is that nearly half the HTML elements are permanently hidden by the analog theme’s CSS. This can be an indication that you’ve misidentified the view objects. In this case, I think it’s pretty obvious that the objects I originally identified when creating the digital clock, that is, active digits composed of lit or unlit LED bars, simply are not present in the analog clock.

Antipattern: Having sections of permanently hidden HTML is an antipattern.

What to do?: Review your objects and wireframes. You may have misidentified some objects, or your application may have changed significantly enough over time that the objects you had originally, and correctly, identified are no longer present. Either way, it’s time to revisit the wireframes and refactor.

Trying to shoehorn an analog display into the digital clock was fun, but more importantly, I think it helped to identify some OOCSS antipatterns. Hopefully these will help us all avoid some pitfalls!

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Fri, 22 Oct 2010 10:14:00 -0700 Font-based digital clock theme using only CSS http://blog.briancavalier.com/font-based-digital-clock-theme-using-only-css http://blog.briancavalier.com/font-based-digital-clock-theme-using-only-css

Ever since Daniel posted his binary mod of my digital clock, I’ve been thinking about other ways to push the limits of the clock using only CSS. At JQCon, I also talked to a few folks between sessions who had wondered the same thing. So, I’ve decided to give it a go.

One of the first ideas I had was to try to use fonts instead of the LED divs to show the clock digits. So, here you go.

It turned out to be fairly easy, and required zero changes to the Javascript view controller. The view controller simply passes the same messages to the view as it did before. In other words, the view controller relies on a message-passing-based view API to which the OOCSS responds. That API is unchanged in this version. To verify, you can hop on over to Daniel’s binary mod, which references my JS directly, and see that it still works.

It also required only superficial changes to the HTML:

  1. I added the button for the new theme in the row of theme buttons.
  2. I added “hour” and “minute” classes to the digits representing hours and minutes. This change was not necessary to support the new font-based theme, but makes the hours and minutes consistent with the seconds, which already had the class “second”.

The key changes were, of course, in the CSS, and here are some of the most relevant bits.

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/* Hide the LEDs */
.white .digit .element {
display: none;
}
/* Use :before to create a new block in which
to display the numbers */
.white .digit:before {
display: block;
height: 100%;
margin: -20px 0 0 -20px;
font-family: "Bank Gothic", "Futura", "Arial";
font-size: 250px;
opacity: .9;
text-align: left;
color: rgb(255, 255, 255);
text-shadow: 0 0 30px rgb(0, 200, 255);
}
/* Seconds are smaller */
.white .digit.second:before {
font-size: 110px;
}
/* Use :before content to inject the digits
Also, hide the initial zero in 12hr mode,
and adjust the widget of the "1" digits
to make the display look nicer */
.white .d0:before {content: "0";}
.white .hr12 .d0:first-child:before {display: none;}
.white .d1:before {content: "1";}
.white .d1 { width: 100px; }
.white .second.d1 { width: 40px; }
.white .d2:before {content: "2";}
.white .d3:before {content: "3";}
/* And so on ... */

The comments pretty much say it all, but basically it hides the LEDs and then uses :before content to inject the font-based digits.

One thing I hadn’t thought about before I actually ran it the first time, was that the “1” digit is much thinner than all the others, so I had to forcibly set a specific width for it (in both hours/minutes and the smaller seconds). Without that specialization, the clock looks too sparse when there is a “1” (or several “1"s) being displayed. Yet another win for the OOCSS base and specialization pattern.

I think this theme looks pretty good (although I’m still partial to the LEDs), but if you have suggestions for how to tweak it, I’d love to hear them. Also, if you have an idea for how to push the envelope, feel free to leave a comment, or tweet it up!

Stay tuned for more envelope pushing …

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Tue, 14 Sep 2010 07:15:00 -0700 The Power of MVC: Binary Clock mod http://blog.briancavalier.com/the-power-of-mvc-binary-clock-mod http://blog.briancavalier.com/the-power-of-mvc-binary-clock-mod

When I created my digital clock, one of the things I wanted to show was how OOCSS and MVC could be used to provide a clean, clear separation of concerns between the View, i.e. HTML and CSS, and the View Controller, i.e. Javascript. Along those lines, I had always intended for it to be possible to slap a different View onto the clock with no mods to the View Controller, but the proof is in the pudding, right?

Along came Daniel Lamb, who put that to the test, and created his spiffy binary clock mod.

He created a slightly modified View structure for the binary clock display in his HTML, and then cleverly applied OOCSS principles to inherit from my original OOCSS. Most interestingly, though, notice that he didn’t change a single line of code in the JS View Controller. In fact, he referenced my JS View Controller directly in his script tag. Because CSS classes are used as a message passing mechanism, and his View responds to the same messages, the binary clock works perfectly.

I'd like to thank Daniel for creating such a cool mod and perfectly illustrating the powerful separation of concerns that OOCSS and MVC can provide.

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Wed, 08 Sep 2010 08:11:00 -0700 The OO in OOCSS, and direct style manipulation http://blog.briancavalier.com/the-oo-in-oocss-and-direct-style-manipulation-0 http://blog.briancavalier.com/the-oo-in-oocss-and-direct-style-manipulation-0

In my recent post, Building a digital clock with OOCSS and MVC, I mentioned that I believe direct style manipulation is not a good engineering practice, and then promptly punted on explaining why until a later post. This was going to be that post, and then John Hann went and laid out many of the points I was going to make.

I have more I’d like to add, so jump over to his post, cujo.js — OOJS, OOCSS, and OOHTML — Part 1 (OOCSS for Engineers) and come back. He specifically touches on direct style manipulation in the sections OOCSS State and OOCSS decreases risk.

The major points he makes are that direct style manipulation:

  1. leads to complex branching code as runtime specialization and state inheritance becomes wider and deeper, as it does in real applications,
  2. puts presentation logic in Javascript, thus thwarting many benefits of separation of concerns and expertise among the team of CSS designers and Javascript engineers,
  3. tightly couples things that shouldn’t be,
  4. is usually less cpu-efficient than fully leveraging a good browser’s CSS engine,

These are great points, and I agree with them.  I’d like to expand on #s 1 and 2 a bit, and talk about a few other reasons in the context of the “OO” in OOCSS.

The OO in OOCSS

Object-oriented means “with a focus on objects”. It is a way of thinking about a problem and how to structure potential solutions. There are programming languages, such as Java, C++, C#, and even Javascript, that provide features to make it easier to apply and enforce OO principles, but a good developer can apply these principles in any language.

Some of the fundamentals of OO are abstraction, inheritance, polymorphism, and encapsulation, among others. Yeah, they’re all 30 point scrabble words, but more importantly, they are time-tested software engineering principles.

If OO means “with a focus on objects”, it seems logical to say OOCSS means, “with a focus on CSS objects”, and I believe there is a huge amount of value to be had in thinking of HTML and CSS as defining View Objects. I’d love to write about how various OO principles apply to OOCSS, and maybe someday soon I will, but for now, I’d like to look at how direct style manipulation violates two of them in particular: inheritance and encapsulation.

Inheritance

I previously wrote about the power of ancestor specializations and state changes affecting changes in descendants, and John goes into even more detail about it. Part of the reason it is so powerful is that it works in harmony with the “C” in CSS, the Cascade.

Using direct style manipulation logic essentially moves specialization and state inheritance from the CSS cascade to procedural Javascript. I think this is bad for two reasons:

  1. Duplicating the cascade moves the mechanism from the browser’s super-fast style engine, to the fairly-fast-but-way-slower-than-the-browser Javascript VM. Don’t think there’s a difference? Check out scripty2’s comparison of hardware accelerated CSS3 transitions vs. Javascript-driven animation

  2. Procedural code is less-easily checked by IDE’s, and is more risky to change than declarative CSS rules. I’d also argue that a well-organized set of CSS rules will visually communicate the cascade, and thus specialization order, more quickly and clearly than procedural branching. To draw an analogy with another popular OO language, which is faster and easier to get right: declaring a Java subclass via “class MySubclass extends MySuperclass” and letting the compiler do the heavy lifting, or writing the Java code that generates the bytecode for MySubclass?

Encapsulation

Encapsulation is the principle of bundling the state with operations that retrieve and modify that state, as well as the idea that only those operations should access the state directly. To put it in terms of objects, an object is responsible for maintaining and controlling access to its own state by exposing only those operations which other actors are allowed to perform on its state.  The other actors in the system must send messages (via exposed operations) to an object to request state changes. The object itself elects how to affect the state change, or even whether to affect it at all.

Without this access control and message passing, it would be much easier to “reach in” and alter the internal state of an object, potentially corrupting it if you don’t understand all the intricacies of its invariants. With access control, an object is protected against corruption, and your application is protected against a corrupted object wreaking havoc.

Most Object Oriented programming languages have built-in mechanisms for declaring access control and enforcing encapsulation, e.g. public, private, protected, and default or package-level access in Java. Even in Javascript, which is a much more malleable, you can use closures to achieve private encapsulation—different mechanism, similar effect.

There is no encapsulation mechanism built into HTML or CSS. The only mechanism that exists is engineering diligence.

Encapsulation, OOCSS, and View Objects

The objects defined by OOCSS are View Objects. The HTML node ancestor/descendant relationships, in conjunction with the OOCSS specializations and state, define these objects. Their “state”, in the OO/encapsulation sense, is their style. For example, consider an HTML/OOCSS View Object that is a stylized button. It’s encapsulated state may contain height, width, background-color, background-image, background-position (maybe using CSS sprites for button states), borders margins, padding, etc. These were probably carefully crafted by a CSS designer to produce a button that looks great and has interesting and useful visual cues on hover, when pressed, etc.

Javascript View Controllers contain logic about when View Objects should change state, and to what states they should change. When View Controllers use direct style manipulation, they are “reaching in” and directly changing the encapsulated state of View Objects, potentially corrupting their presentation state by breaking the layout and presentation invariants setup by the designer.

With enough time and care, a JS engineer could certainly duplicate the invariants across some or all possible presentation states, such as, in the case of a button, idle, :hover, and :active, but then would also have to account for other axes of change, such as browser differences (e.g. box model, rgba or hsl colors, opacity, transitions, etc.). The conditionals in the Javascript would start to add up, and probably produce horribly unmaintainable code. John showed in his simple example and the text that follows, how the branching could get to O(n^m) complexity.

Doing so would also spread the presentation details out into at least 2 places, the CSS and the Javascript (or more if the presentation is being modified in several places in the JS!). Each time the presentation needed to be modified, it would require looking in both places, and would probably require involving both the CSS designer and the Javascript engineer.

I'll also point out again that this kind of conditional logic is essentially duplicating the cascade, which is a bad idea for the reasons I listed above.

OOCSS: The Right Tool for the Job

CSS has a powerful inheritance mechanism in the cascade, and its declarative style, IMHO, provides a simple and expressive way to setup presentation across many view states.  It is, in that regard, a declarative language for presentation state machines. The “OO” in OOCSS is a powerful way of thinking about HTML + CSS as View Objects, and gives designers and developers the right tools to declare and manage them.

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Mon, 30 Aug 2010 06:06:00 -0700 Building a digital clock with OOCSS and MVC http://blog.briancavalier.com/building-a-digital-clock-with-oocss-and-mvc http://blog.briancavalier.com/building-a-digital-clock-with-oocss-and-mvc

I’ve been thinking a lot about OOCSS and MVC-in-the-browser over the past months. These certainly aren’t things I invented, but what I found is that my own philosophy of building applications for the web had evolved to include these concepts. It was only later that I learned that some really smart folks had also been thinking about these things, and had given them names.

So, I created this digital clock app as a simple example of some of the concepts I have been applying to build apps with OOCSS and MVC.

Very shortly after that, I got a walkthrough of John (unscriptable) Hann’s ambitious cujo.js project, and I was blown away by two things. First, he and I had basically come to believe many of the same things about applying OOCSS and MVC, and second, he had actually wrapped those things up in an incredibly simple and intuitive API inside cujo.js.

Let’s get down to business, and look at a few of these techniques in practice. I’ll hope that some theory will fall out of it as I write.

“Is A” and Specialization

Here’s a bit of HTML from the clock.

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<div class="slot digit">
<div class="element bar center top"></div>
<div class="element bar center middle"></div>
<div class="element bar center bottom"></div>
<div class="element bar left top"></div>
<div class="element bar left bottom"></div>
<div class="element bar right top"></div>
<div class="element bar right bottom"></div>
</div>

Some of the classes here set up “is a” relationships. Even though the order of classes in HTML doesn’t matter, I’ve arranged them left to right from general to specific, because I think that makes the most sense. The node “is a” slot—an admittedly awful name for an area in which the clock will display something. Also, it “is a” digit, which in this case, is a specialization of slot that will display a digit.

Farther down, there is another specialization of digit:

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<div class="slot digit second">
<div class="element bar center top"></div>
<div class="element bar center middle"></div>
<div class="element bar center bottom"></div>
<div class="element bar left top"></div>
<div class="element bar left bottom"></div>
<div class="element bar right top"></div>
<div class="element bar right bottom"></div>
</div>

This node is still a digit, but more specifically, it’s a second, as opposed to a minute or hour. Looking at the rendered clock, you can see that seconds are smaller than minutes and hours—the presentation of seconds has been specialized to be smaller.

States, Views, and View Controllers

If you watch the DOM while the clock is running you’ll notice the digit nodes getting the classes d0 through d9. Obviously, this is driven by Javascript. That Javascript is acting as a View Controller. The digit is the View, and the Javascript driving, or controlling, it is the View Controller.

The classes d0 – d9 represent the possible states that the digit may be in. By changing the class, the View Controller is telling the View to change state. The View still “is a” digit, but it has changed state, for example, from a zero to a one. I guess you could say it “was a” zero and now it “is a” one, and that it’s actually mutating to another specialization rather than changing state. I think that’s a reasonable way to think about it—it’s just not how my brain works, so for me, it’s state.

The digits and the state transitions manifest themselves in the browser with the help of CSS. Here’s a bit of the CSS.

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/* All elements, when not "turned on", leave slight ghosting */
.element {
opacity: .1;
}

/* LED bars (specialization of element) that make up the digits */
/* Default theme is green, box-shadow glow, slightly rounded corners */
.bar {
background-color: #0f0;
border-radius: 4px;
-moz-border-radius: 4px;
position: absolute;
-webkit-box-shadow: 0 0 20px #0f0;
-moz-box-shadow: 0 0 20px #0f0;
-webkit-transition: all 400ms ease;
-moz-transition: all 400ms ease;
}

/* Digits */
/* Light up the bars necessary to make a zero. Everything but the center bar.
top, bottom, top-left, bottom-left, top-right, bottom-right */
.d0 .center.top, .d0 .center.bottom, .d0 .left.top, .d0 .left.bottom, .d0 .right.top, .d0 .right.bottom {
opacity: .9;
}

/* The first zero in 12 hour mode should always be turned off,
i.e. don't show leading zeros in 12 hour mode, but _do_ show them in 24 hour mode.
Instead of doing a JS computation for this, it can be done here */
.hr12 .d0:first-child .bar {
opacity: .1 !important;
}

/* Light up the bars necessary to make a one. Just the top-right and bottom-right */
.d1 .right.top, .d1 .right.bottom {
opacity: .9;
}

This CSS describes what a digit looks like when it’s in state d0 and d1. In addition to describing the resulting state’s presentation, it is also describing the state transition itself—that is, how (in the visual sense) the digit moves from one state to another using CSS3 transitions.

Specializations, State, and Ancestry

One thing that is subtle, but I feel is extremely important here, is that by changing the state of the digit, the state of the elements within the digit (i.e. the glowing bars) is being affected. There are no direct state changes to the bars, yet they are changing. The current state of each bar is defined by the hierarchy of classes above it in the DOM plus its own classes. Or, to put it in more general terms:

The current “whole state” (borrowing a term from a recent conversation with John) of a particular View is defined by the specializations and state of its ancestors plus its own specializations and state.

There’s no direct manipulation of nodes at the leaf level via Javascript. I’ll talk about why I believe doing direct style manipulation, such as $.css or dojo.style, is not a good engineering practice in another post, but, the key here is that by simply issuing a state transition on an enclosing View, state changes can be affected on its sub-Views.

Let’s look at why that’s interesting and useful on a practical level.

Back to Practical

So, the clock has a Javascript View Controller telling the View to change state which consequently alters the state of its sub-Views, HTML which is defining the structure of that View, and CSS that is describing the presentation of the states and the transitions between them. IMHO, that’s a very powerful separation of concerns.

Imagine you wanted to change the look of the digits by giving the bars beveled ends as some digital displays have, or you wanted to make the entire clock larger or small, or size it using percentages instead of pixels, or introducing a radical new presentation and color theme. You would not need to touch the View Controller. There are several reasons that is a good thing, IMHO, two of which are:

  1. The changes could be made by the team’s CSS designer, without involving a JS engineer, and
  2. Changing procedural code, like JS, is typically more risky than changing declarative code, like CSS.

This separation of concerns provides similar benefits on the View Controller side. When I decided to add support for 24 hour display, all I had to do (ignoring adding the new View components for selecting 12 or 24 hour time, and storing the preference) was to make a small change to the hour computation in the View Controller Javascript, issue slightly different state changes for the hour digits, and ensure that the AM or PM elements are always in the off state.

I didn’t need to make any changes to the CSS or HTML. Engineers can craft the JS, and the designers can craft the CSS. Sure, you might play both roles, but that’s not the case with every team, especially in large, complex apps, with many Views, company wide design standards, branding, and a small army of awesome designers complimented by an equally awesome army of software engineers.

I am very excited about building apps using these techniques, and I am especially excited after seeing John’s work so far on cujo.js. If it turns out to embody these concepts like I think it will, it’s gonna be a very powerful platform. I’ll certainly be keeping an eye on it.

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Thu, 26 Aug 2010 11:54:00 -0700 CSS3DC in 10k http://blog.briancavalier.com/css3dc-in-10k http://blog.briancavalier.com/css3dc-in-10k

I entered my digital clock in the 10k Apart challenge.  It keeps time and looks good too, all in less than 10k of HTML5, CSS, and JS.  Go take a look, and if you like it, please vote it up!

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Tue, 24 Aug 2010 06:25:00 -0700 CSS3DC gets a new home, 24hr time, localStorage, all in less code http://blog.briancavalier.com/css3dc-gets-a-new-home-24hr-time-localstorage http://blog.briancavalier.com/css3dc-gets-a-new-home-24hr-time-localstorage

I decided to give the CSS3 digital clock a new home, and in the process, couldn't help but hack on it a bit more.  It has a setting for 12 or 24 hour time, and uses localStorage to remember both your 12/24 and color settings, so you can keep the time you want, in the color you want, whenever you want.  Despite all of that, the HTML, CSS, and JS are a bit lighter and more streamlined now as well.

Oh, and it looks great as an OS X dashboard widget.  You can use Safari's web clip feature to snag it and put it on your dashboard!

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Thu, 15 Jul 2010 11:40:00 -0700 CSS3 Digital Clock http://blog.briancavalier.com/css3-digital-clock http://blog.briancavalier.com/css3-digital-clock

You know how the saying goes, something like "when all you have is a hammer, everything looks like a nail". Lately, as you may have guessed from some recent posts, my favorite hammer has been HTML5 plus CSS3. Recently I've been looking for a good alarm clock app for my iPhone, and seeing some of the gorgeous digital clock apps got me wondering if I could create one using CSS3.

After a couple hours hacking last night, I think I ended up with something that looks pretty good. There are generous helpings of CSS3 gradients, rgba, and opacity, a side of CSS transitions, and a sprinkling of skew and scale transforms. There's a side of dojo to pull it all together.

So, go keep some time, and pick your favorite color. Oh, and let it sit for a bit ... you never know what might happen.

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier
Thu, 01 Jul 2010 05:26:00 -0700 CSS layers and glass/gradient buttons http://blog.briancavalier.com/css-layers-and-glassgradient-buttons http://blog.briancavalier.com/css-layers-and-glassgradient-buttons

I threw together a set of image-less glass and gradients buttons last night.  They use a flat color behind a partially-transparent CSS3 gradient to create an overall glass or gradient effect.  The nice thing about it is that the gradient style can vary independent of the color, and you don't have to play with a color selector or do color math to get the gradients to look nice.  You can simply setup one gradient and then you can change the flat color to suit what you need.

One obvious problem is that it won't work in browsers that don't support CSS gradients, and in browsers that do support gradients, but don't support color stops, such as IE8, you can't do the glass effect using this techique.

Another problem I found is with Firefox, and presumably any browser that uses gecko.  When using a border-radius on the outer button element, it doesn't fully extend the inner element to the edges of the button, so you get a nasty flat colored "border" (not actually a CSS border).  Take a look in Firefox to see what I mean.  It's a shame, because the technique works very well in WebKit.

Anyway, check it out here.

Update (7/2/2010): I added a hack to "remove" the nasty borders in Firefox by introducing a negative margin on the inner gradient overlay.  It stretches the overlay out to the edges of the button.  It works, but I really don't like it at all.  I hope Firefox fixes their gradient rendering with border-radius to work "correctly"--or rather, what I feel is correct ... like WebKit does it.

On a related note, Safari on the iPhone in iOS4 also renders the gradient overlays incorrectly.  It leaves large gaps on the left and right.  So, there's something different about that version of WebKit as well.

I also added IE gradients, which don't support color stops, so all the buttons will all appear to be straight two-color gradients.  They still look decent, but not nearly as snazzy as in WebKit and FF.

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http://files.posterous.com/user_profile_pics/800723/IMG_2350-crop1.jpg http://posterous.com/users/4bmW4R4xz0GZ Brian Cavalier Brian Brian Cavalier