Road to Mac OS X Leopard: an extensive look at Preview 4.0
Preview has two standard Toolbars: one for graphics and a slightly different one for PDFs, which adds a text selection tool and a search bar. The simplified new PDF toolbar layout makes more sense than Tiger's PDF Preview tools, which grouped together a "Tool Mode" bar selecting between move, select text, select region, and annotate modes. In Leopard, you get Move, Text, and Select buttons that make more sense.
Apple hid all of the new annotation and markup features from the default Toolbar. You'll have to customize the Toolbar to add them. You can choose between adding a compact drop down Annotate button or a more sprawling four button bar that displays the drop down menu as a series of buttons: Oval, Rectangle, Note, Link.
In either case, you can annotate PDFs by drawing an oval or rectangle region, adding a Note comment, or by creating a Link region that can be set to hyperlink to another page inside the PDF, or to an external URL.
Underline, strikeout, or highlight a text selection within a PDF using standard markup that is compatible with Adobe Acrobat and other PDF editors.
Graphic files (as opposed to PDFs) can also be similarly annotated with boxes, ovals, note comments, and free-form arrows, although the tools are slightly different. This makes it easy to add simple modifications to graphics without moving to a more significant graphics tool. In effect, Preview is now like an ultra simple version of Keynote. However, as new features get added to Preview, it stops becoming a free "graphics viewer plus" and begins to look like a graphics tool that doesn't quite do everything one might imagine it should.
Rather than adding text with a standard insertion point, Preview has you select a region of where your text box will go. You can edit the box later, but it isn't quite as intuitive in how it works, and it's not consistent with other iLife and iWork apps. Preview seems to have a number of oddball edges, including its Inspector panel, which takes a step closer to matching the standard inspector found in the iLife apps, but doesn't quite make it there.
Preview's Image Correction panel does a bit better, making the jump from an old style white panel to the more inviting and sophisticated translucent panel of iPhoto. Compare the Leopard version of Preview's Inspector and Adjustment tools (below) with the Tiger version below them.
Another handy tool in Preview 4.0 is the adjust size sheet, which drops down to allow a resizing of width and height based on inches, pixels, or percent change. A "fit into" drop down allows you to select a common resolution, resizing a graphic or photo to fit as a standard desktop background, for example.
Two new tools for extracting portions of a graphic in Preview are both powerful and unique. The first is familiar to anyone using iLife or iWork 08: Apple calls it "Instant Alpha," and it makes it easy to select and remove an object from its background. It works like a magic selection wand to select colors for deletion, but only requires clicking on the background and dragging to blow away the surrounding area. Once the selection matches the result you want, you hit return and your graphic is cleanly removed from its background.
In the iPhone image below, the Instant Alpha tool was used to select a 4% range of blacks representing the background color. This automatically masked off the image, and set the surrounding black area to be transparent (using the alpha channel), all without messing with any of the blacks in the image. This is a very useful tool and extremely easy to use.
For images against a busy background, selecting the undesired background to remove by color ranges using Instant Alpha can be too difficult or too slow. Preview includes a new tool called Extract Shape that intelligently helps you cut out an image. Of course, there's also the lasso selection tool, but drawing a clean freehand selection isn't very easy. Professionals commonly create a detailed mask using Bézier curves to isolate images from their background, but that isn't very easy or intuitive either.
Extract Shape gives you a fat, translucent red marker outline to draw around the desired shape. Once finished doing a rough outline, the tool transforms it into a series of points outlining the area (below left), allowing you to delete extra points or move them around as desired. After doing any desired cleanup, hit return and the system analyzes the selection, then gives you an opportunity to use Instant Alpha to polish away any remaining rough bits to cleanly extract away the background (below right).
The resulting graphic (below left) has an alpha channel background that can be used in a composition created within Keynote, Pages, or iWeb (below right). With iPhoto's retouch brush and a smoothing/burning/dodging tool, Preview could be a great basic photo tool. Add some brushes and it could be the painting app missing from iLife. Not bad for one of the least exciting applications in Mac OS X.
And that's Preview 4.0.