Almost every new client these days wants a mobile version of their website. It’s practically essential after all: one design for the BlackBerry, another for the iPhone, the iPad, netbook, Kindle — and all screen resolutions must be compatible, too. In the next five years, we’ll likely need to design for a number of additional inventions. When will the madness stop? It won’t, of course.
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Above, the h1 element holds the illustration as a background, and the image is aligned according to the container’s background (the heading).
This is just one example of the kind of thinking that makes responsive Web design truly effective. But even with smart fixes like this, a layout can become too narrow or short to look right. In the logo example above (although it works), the ideal situation would be to not crop half of the illustration or to keep the logo from being so small that it becomes illegible and “floats” up.
Flexible Images
One major problem that needs to be solved with responsive Web design is working with images. There are a number of techniques to resize images proportionately, and many are easily done. The most popular option, noted in Ethan Marcotte’s article on fluid images but first experimented with by Richard Rutter, is to use CSS’s max-width for an easy fix.
img { max-width: 100%; }As long as no other width-based image styles override this rule, every image will load in its original size, unless the viewing area becomes narrower than the image’s original width. The maximum width of the image is set to 100% of the screen or browser width, so when that 100% becomes narrower, so does the image. Essentially, as Jason Grigsby noted, “The idea behind fluid images is that you deliver images at the maximum size they will be used at. You don’t declare the height and width in your code, but instead let the browser resize the images as needed while using CSS to guide their relative size”. It’s a great and simple technique to resize images beautifully.
Note that max-width is not supported in IE, but a good use of width: 100% would solve the problem neatly in an IE-specific style sheet. One more issue is that when an image is resized too small in some older browsers in Windows, the rendering isn’t as clear as it ought to be. There is a JavaScript to fix this issue, though, found in Ethan Marcotte’s article.
While the above is a great quick fix and good start to responsive images, image resolution and download times should be the primary considerations. While resizing an image for mobile devices can be very simple, if the original image size is meant for large devices, it could significantly slow download times and take up space unnecessarily.
Filament Group’s Responsive Images
This technique, presented by the Filament Group, takes this issue into consideration and not only resizes images proportionately, but shrinks image resolution on smaller devices, so very large images don’t waste space unnecessarily on small screens. Check out the demo page here.
The data-fullsrc is a custom HTML5 attribute, defined in the files linked to above. For any screen that is wider than 480 pixels, the larger-resolution image (largeRes.jpg) will load; smaller screens wouldn’t need to load the bigger image, and so the smaller image (smallRes.jpg) will load.
The JavaScript file inserts a base element that allows the page to separate responsive images from others and redirects them as necessary. When the page loads, all files are rewritten to their original forms, and only the large or small images are loaded as necessary. With other techniques, all higher-resolution images would have had to be downloaded, even if the larger versions would never be used. Particularly for websites with a lot of images, this technique can be a great saver of bandwidth and loading time.
This technique is fully supported in modern browsers, such as IE8+, Safari, Chrome and Opera, as well as mobile devices that use these same browsers (iPad, iPhone, etc.). Older browsers and Firefox degrade nicely and still resize as one would expect of a responsive image, except that both resolutions are downloaded together, so the end benefit of saving space with this technique is void.
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Stop iPhone Simulator Image Resizing
One nice thing about the iPhone and iPod Touch is that Web designs automatically rescale to fit the tiny screen. A full-sized design, unless specified otherwise, would just shrink proportionally for the tiny browser, with no need for scrolling or a mobile version. Then, the user could easily zoom in and out as necessary.
There was, however, one issue this simulator created. When responsive Web design took off, many noticed that images were still changing proportionally with the page even if they were specifically made for (or could otherwise fit) the tiny screen. This in turn scaled down text and other elements.
(Image: Think Vitamin | Website referenced: 8 Faces
Because this works only with Apple’s simulator, we can use an Apple-specific meta tag to fix the problem, placing it below the website’s section. Thanks to Think Vitamin’s article on image resizing, we have the meta tag below:
Setting the initial-scale to 1 overrides the default to resize images proportionally, while leaving them as is if their width is the same as the device’s width (in either portrait or lanscape mode). Apple’s documentation has a lot more information on the viewport meta tag.
Custom Layout Structure
For extreme size changes, we may want to change the layout altogether, either through a separate style sheet or, more efficiently, through a CSS media query. This does not have to be troublesome; most of the styles can remain the same, while specific style sheets can inherit these styles and move elements around with floats, widths, heights and so on.
For example, we could have one main style sheet (which would also be the default) that would define all of the main structural elements, such as #wrapper, #content, #sidebar, #nav, along with colors, backgrounds and typography. Default flexible widths and floats could also be defined.
If a style sheet made the layout too narrow, short, wide or tall, we could then detect that and switch to a new style sheet. This new child style sheet would adopt everything from the default style sheet and then just redefine the layout’s structure.
Here is the style.css (default) content:
/* Default styles that will carry to the child style sheet */html,body{ background… font… color…}h1,h2,h3{}p, blockquote, pre, code, ol, ul{}/* Structural elements */#wrapper{ width: 80%; margin: 0 auto; background: #fff; padding: 20px;}#content{ width: 54%; float: left; margin-right: 3%;}#sidebar-left{ width: 20%; float: left; margin-right: 3%;}#sidebar-right{ width: 20%; float: left;}Here is the mobile.css (child) content:
#wrapper{ width: 90%;}#content{ width: 100%;}#sidebar-left{ width: 100%; clear: both; /* Additional styling for our new layout */ border-top: 1px solid #ccc; margin-top: 20px;}#sidebar-right{ width: 100%; clear: both; /* Additional styling for our new layout */ border-top: 1px solid #ccc; margin-top: 20px;}
Media QueriesCSS3 supports all of the same media types as CSS 2.1, such as screen, print and handheld, but has added dozens of new media features, including max-width, device-width, orientation and color. New devices made after the release of CSS3 (such as the iPad and Android devices) will definitely support media features. So, calling a media query using CSS3 features to target these devices would work just fine, and it will be ignored if accessed by an older computer browser that does not support CSS3.
In Ethan Marcotte’s article, we see an example of a media query in action:
This media query is fairly self-explanatory: if the browser displays this page on a screen (rather than print, etc.), and if the width of the screen (not necessarily the viewport) is 480 pixels or less, then load shetland.css.
New CSS3 features also include orientation (portrait vs. landscape), device-width, min-device-width and more. Look at “The Orientation Media Query” for more information on setting and restricting widths based on these media query features.
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One can create multiple style sheets, as well as basic layout alterations defined to fit ranges of widths — even for landscape vs. portrait orientations. Be sure to look at the section of Ethan Marcotte’s article entitled “Meet the media query” for more examples and a more thorough explanation.
Multiple media queries can also be dropped right into a single style sheet, which is the most efficient option when used: