Group items tagged

The iPad has a bigger screen, and so it has a bigger resolution. With the iPhone 4, however, Apple did something different: they increased the resolution without changing the physical size of the screen. This makes for a higher pixel density, pixels are smaller and more tightly packed. In one square inch of the iPhone 4’s screen there are around 106 thousand pixels (at 326 PPI, or Pixels per Inch), while the older models have only about 26 thousand (at 163 PPI) in an inch – 4 times less! This makes graphics on the screen seem like continuous lines, because your eye can’t see the individual pixels. Apple calls this technology the “Retina Display” because they claim the human eye (the retina) can’t physically see the pixels at this resolution.

Using Two Images The official way of adding high-resolution support to your application is by having two versions of each image, one in “regular” resolution and one in double resolution. Whenever your application is viewed on the Retina Display, the larger image will be loaded automatically. This method allows for full and precise control of how your application will look in each case, and is very easy to apply to your existing applications. The full size image file should be named however you want, such as “Button.png”. Use this image name in your code and Interface Builder wherever you want to reference the image. The double-size image should be twice the size of its matching smaller image and named exactly the same with “@2x” appended to the name. In our example, we would name it “Button@2x.png”. Unfortunately, this technique will not work on the iPad; a pixel-doubled application will not load the higher resolution resource. This will probably be addressed in the future iOS 4 update which is scheduled to come to iPad this fall.

According to a FAQ on Picasa's support site, the photo-sharing service provides up to 1 GB of free storage for photos and videos to its users. But since Google+ actively encourages storing and sharing photos - its Android app even offers an "instant upload" option - there may have been some concern about storage limits among Picasa users. As it turns out, there's nothing to worry about. If you're signed up for Google+, photos up to 2048x2048 pixels and videos up to 15 minutes long won't count towards this free storage limit. And Google will automatically resize photos for you when you upload them to Google+, so they stay under the free size limit. That means only photos uploaded directly to Picasa Web Albums over the 2048x2048 size will count towards the 1 GB of free storage, explains Google. And when that limit is reached, photos will be automatically resized. Meanwhile, for non-Google+ users, there are slightly stricter rules: photos up to 800x800 and videos up to 15 minutes won't count towards free storage. Again, when the 1 GB limit is reached, larger photos will be resized down. Simply put, this means that whether you're on Google+ or not, Picasa offers unlimited free storage for photos and videos (under 15 minutes). The difference is that Google+ users can upload higher resolution photos to Plus/Picasa without being penalized.

App Store Icon 512x512 (scaled down to 175x175 for display in the store)

Application Icon 114x114 (iPhone 4) 57x57 (older iPhones) 72x72 (iPad)

Spotlight Search Results and Settings Icon 58x58 (iPhone 4) 50x50 (Spotlight results for iPad) 29x29 (settings for iPad and older iPhones)

Exporting & Saving One thing that SVG can’t do is save the resulting image as a bitmap. It’s easy for <canvas> because the element is already a bitmap in the first place! The canvas can export its image to a data URL (e.g., data:image/png;base64,iVBORw0KGg...). This data may then be rendered in the browser, which could then be saved or dragged to the desktop, used in a new canvas, and so on. The browser must support PNG images, and it may have varying support for GIF and JPG. For our example, we’ll stick with PNG since it supports alpha transparency, and where we haven’t drawn on the canvas, it’ll be transparent. To get the data URL, we simply call canvas.toDataURL('image/png'). Note that we’re calling toDataURL() on the <canvas> element, not on the 2D context. This is because we’re getting all the pixels in the canvas, not just the pixels in a particular context. So taking the example we’ve put together already, we’ll make the browser redirect to a PNG version of the image when a user clicks on the <canvas> element (a contrived example, I know!): canvas.onclick = function () {  window.location = canvas.toDataURL('image/png');};

LEGOs and Lincoln Logs are for Luddites. Sifteo cubes are the new building blocks. Each cube has a 128-pixel color LCD screen, wireless connectivity, a 32-bit ARM microprocessor, and an accelerometer that responds to tilting and stacking. You can arrange them to create everything from vocabulary puzzles to building challenges, all of which can be enjoyed by as many people as you can crowd around the coffee table.

Sifteo founders Jeevan Kalanithi and David Merrill previewed the cubes at TED 2009 when they were grad students at MIT. The cubes debuted at CES this year. The design marries classic tactility with new hardware and software. “Sifteo cubes are the first gaming solution to deliver truly hands-on play,” Merrill said. “[The cubes combine] the latest in embedded computing and sensing technology with a timeless play style.”