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The Power of Preview: Pulling Files in Preview
Adam C. Engst
So much criticism has been heaped on the likes of iTunes and Photos
that it can be easy to forget the software that Apple gets right ' apps
that are both simple and powerful. There may be no better example of
this than Preview, which has been built into OS X from the beginning.
On the surface, Preview is a simple image and PDF document viewer,
although it can also open iWork and Microsoft Office files. Beyond that
veneer of simplicity, though, Preview can do so much more. To get a
taste of Preview's power, let's take a look at how you open images and
documents in Preview, starting with the obvious ways and moving on to
things you may not know.
Of course, if Preview is your default app for images and PDFs, you can
open those files by double-clicking them or selecting them in the
Finder and pressing Command-O. Or drag a file to the Preview icon,
either in the Finder or in the Dock. Nothing new there.
Slightly more subtle is opening files through Quick Look, which we
covered in detail in '[1]OS X Hidden Treasures: Quick Look,' (12
February 2016). In the Finder, select an image or PDF file and press
the Space bar or Command-Y to open it in Quick Look. Then click the
Open With Preview button at the upper right.
[2][tn_Quick-Look-desktop.jpg]
Although Preview is the default app for most image types and for PDFs,
it's possible that another app, like Adobe Reader, has taken over for
Preview. If you want to change the default app for a file type, here's
how to do that:
1. Select a file of the desired type in the Finder.
2. Choose File > Get Info (or press Command-I) to open the Info
window.
3. Under Open With, choose Preview from the pop-up menu (highlighted
in red in the screenshot below). If necessary, click the arrow to
the left of Open With to expand that section.
4. Click Change All to make Preview the default viewer for all files
of that type.
[3][tn_Get-Info-change-default.jpg]
But that's all Mac 101. Let's look at two of Preview's more interesting
import options.
Import from Cameras -- Here's something you probably didn't know:
Preview can import images directly from cameras and scanners. Better
yet, in Preview's eyes, your iPhone or iPad counts as a camera.
To import pictures from a camera, connect it to your Mac via a USB
cable, open Preview, and choose Import from CameraName (for instance,
Import from iPhone).
A window appears displaying thumbnails of the photos on that camera,
largely mirroring the look and features of Apple's Image Capture
utility (which lives in the Utilities folder inside your Applications
folder). By default, Preview displays the photos in a list, with EXIF
information like the date and time the picture was taken, file size,
resolution, GPS coordinates, aperture size, whether the flash was
fired, and more. Even if you don't want to use Preview to import your
photos, it's a handy way to view all that data.
[4][tn_Preview-camera-import.jpg]
In the lower left, there are buttons to rotate photos, view photos as a
list, or view photos as a grid. To rotate a photo, select it and click
the curvy arrow. You can also adjust thumbnail size with the slider in
the lower right.
When you want to import the photos, you have two options in the lower
right. You can click Import All to get everything or select a few
photos and click Import. Decide where to save the images and click
Choose Destination to put the pictures there.
Import from Scanners -- If you have a scanner attached to your Mac via
USB, you can use Preview to import images and documents from it.
Perhaps not surprisingly, the interface is also nearly identical to
Image Capture's. It's also similar to the window that appears when you
click Open Scanner from the Printers & Scanners pane of System
Preferences. If your scanner doesn't appear, you may need to set it up
first from within the Printers & Scanners preference pane. Once there,
you can also set Preview to open automatically when you press the Scan
button on your scanner, assuming it has one.
[5][tn_Printers-Scanners-pref-pane.jpg]
With the scanner attached and turned on, choose File > Import from
ScannerName in Preview. If the details pane isn't showing already,
click Show Details to display a wide variety of controls for
resolution, size, rotation, format, and image correction. You'll
probably want to choose a resolution higher than 50 dpi (300 dpi is
safe if you're planning to print the scanned document; you might want
to go higher for photos).
[6][tn_Preview-scan.jpg]
Pay special attention to the Auto Selection pop-up menu, which has
three settings: Off, Detect Separate Items, and Detect Enclosing Box.
Preview defaults to Detect Separate Items, which is appropriate for
scanning multiple photos at once but isn't right for scanning a single
sheet of paper. For full-page scanning, choose Detect Enclosing Box,
which tries to detect the edges of the paper and lets you adjust the
scanned area by dragging the selection rectangle's handles. If neither
does quite what you want, you can select the portion of the document to
scan manually by dragging out a rectangle, moving it around, and
resizing it with its handles. For an easier approach when scanning full
pages, choose Edit > Select All (Command-A), and then resize the
selection.
When everything is set to your liking, click Scan. Preview scans the
document and opens it in a new Untitled window. If it doesn't meet your
needs ' this is where you realize that you forgot to reset the
resolution menu from 50 dpi to 300 dpi ' close it without saving.
Otherwise, save and name the document to keep it. If you put multiple
items in the scanner, Preview scans them to separate files, all of
which are shown in a single Preview window.
One last thing. While viewing a PDF, you can add additional pages to it
by choosing Edit > Insert > Page from Scanner. The scanning interface
here is simpler, with only a checkbox to use the scanner's document
feeder, if available, a Rescan button for trying again, and an Add To
Document button. It's not clear how Preview chooses resolution in this
scenario, but it seems to be relatively high. The page is inserted
after the currently selected page, though you can also drag it around
within Preview's thumbnail sidebar.
Take Screenshots -- Those who write about technology have memorized
Apple's [7]keyboard shortcuts to take Mac screenshots. Normal people
who need to take a screenshot only a few times a year should turn to
Preview instead. Just as the previous features also appeared in Apple's
Image Capture utility, the screenshot capabilities are mirrored in
Apple's Grab utility (also stored in the Utilities folder).
In Preview, choose File > Take Screenshot. There you find three
options:
* From Selection: After choosing this command, your cursor becomes a
crosshair. Click and drag the crosshair over the screen area you
wish to capture.
* From Window: Choose this command, and your cursor becomes a camera.
Move the camera cursor over a window and the window turns blue to
indicate that it's selected. Click to take a screenshot of that
window. By default, your window screenshots come with a large
shadow; to remove it, Option-click the selected window.
* From Entire Screen: When you chose this command, a 10-second
countdown begins, which you can cancel by pressing the Esc key.
Once the countdown finishes, Preview takes a screenshot of your
entire screen. If you have multiple screens, Preview creates
screenshots for each one. The timer is useful when you need to set
up the screen in such a way that wouldn't be possible with an
instantaneous screenshot. Although it won't appear in the final
screenshot regardless, you can move the countdown timer bar around
to get it out of your way.
Unlike OS X's screenshot shortcuts, which dump the screenshots on your
Desktop, Preview opens each new screenshot as a PNG file in an Untitled
window, where you can make any modifications you like before saving it.
Simple, but effective.
[8][tn_Preview-marked-up-screenshot.jpg]
Wait, modifications? Yes, that's right, Preview is also a surprisingly
full-featured graphic editor too. But that's a topic for a future
article. Preview may seem unassuming, but it's packed with useful
capabilities, and we'll be looking at more of them in the future.
References
1. http://tidbits.com/article/16254
2. http://tidbits.com/resources/2016-02/Quick-Look-desktop.png
3. http://tidbits.com/resources/2016-02/Get-Info-change-default.png
4. http://tidbits.com/resources/2016-02/Preview-camera-import.png
5. http://tidbits.com/resources/2016-02/Printers-Scanners-pref-pane.png
6. http://tidbits.com/resources/2016-02/Preview-scan.png
7. https://support.apple.com/en-us/HT201361
8. http://tidbits.com/resources/2016-02/Preview-marked-up-screenshot.png