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I like the convenience of being able to crop jpg/png images with Preview, but I would also like to be able occasionally to restrict the aspect ratio of the cropped image. This is useful, for instance, if I want to prepare images for printing in 4x6 or 5x7, while avoiding any surprise cropping made by the photo lab.
I am hoping there is a quick and easy way to do this (i.e., without needing to invoke the behemoth of image editing for this elementary task). Are you aware of one?
In Photos (not iPhoto) click Edit
then Crop
then Aspect, and finally Original
.
As of this writing (August 2016), there is no way to do this using Preview or any other stock program in El Capitan. Photos is nearly stock though, and it's easy enough using Photos.
Photo? Is it an app? Do you have a link to it (either on the web or an App store line?) A quick Google & App Store search isn't showing any obvious results, and I've never heard of this app…
Dec 26, 2021 at 4:50
iPhoto. At some point (not sure when) Apple abandoned (the by-then rather backward and unsalvageable) iPhoto. To avoid confusion, and since the new app was genuinely built from scratch, they named the new app Photo. It is this one that you would install today on BigSur, and perhaps on Monterey—I haven't moved yet.
There is no way to do exactly what you are specifying in Preview.app without doing a bit of math.
Holding down the shift key while using the select tool will force the select box to retain itself in square dimensions, while holding down the option key will open the select box from the center of where you begin your selection, while holding down both shift and option keys will implement both these features simultaneously. After creating the size of the select box that you want, you can use command-K to crop. Using the Adjust Size function in the Tools menu retains the aspect ratio by default.
Not what you asked for, but when using the select tool, you will notice numbers at 2 of the corners of the select box, and if you're very good with math (i.e. know if the numbers showing are multiples of your desired aspect ratio) and have a steady hand, you can accomplish what you are asking for on the fly. Otherwise, you'll have to figure out those dimensions beforehand or one at a time, and manually try to match up the numbers. In the end and in all circumstances, in my experience, mathematics is simply inescapable.
You may want to demo using an application dedicated to exactly what you want to do (rather than seeking functionality that just isn't there from such a simple, although often very useful, application such as Preview.app), for example, photo crop PRO. I personally would not recommend using Mac App Store ;-), but it is also available from the Mac App Store.
Alternatively, for an application far more powerful than either Preview or photo crop Pro, I've discovered darktable, which
"is an open source photography workflow application and RAW developer. A virtual lighttable and darkroom for photographers. It manages your digital negatives in a database, lets you view them through a zoomable lighttable and enables you to develop raw images and enhance them."
darktable can be installed manually, but is also maintained as a port using MacPorts, if you prefer to use package management. I've included step by step instructions for installing MacPorts and darktable below.
Another extremely powerful alternative suggested in another response (I thank you Ecnerwal!) is using the GIMP. The GIMP can be installed manually, or built from source using MacPorts. I've included instructions below on how to install the GIMP using MacPorts. If you know Adobe Photoshop well, you may want to demo using GIMPshop, which very cleverly and conveniently reconstructs the look and feel of the GIMP to appear and behave nearly just like Photoshop... and its all for free.
If you're looking for a mature package management solution, for OS X I recommend MacPorts. MacPorts requires an appropriate version of xcode; xcode_5.1.1.dmg is the most recent version for Mavericks and Mountain Lion, and will require registering for free as an Apple Developer. Once registered and logged in, the link above for xcode will initiate the xcode download.
Get to know MacPorts
Enter these commands using /Applications/Utilities/Terminal.app
curl -Ok https://distfiles.macports.org/MacPorts/MacPorts-2.2.1.tar.bz2
tar xf MacPorts-2.2.1.tar.bz2
cd MacPorts-2.2.1
./configure
make
sudo make install # *not war!*
cd ..
rm -rf Macports-*
sudo /opt/local/bin/port -v selfupdate
export PATH=/opt/local/bin:/opt/local/sbin:$PATH
sudo port -vsc install darktable
sudo port -vsc install gimp
port search photo
If, for whatever reason, you need to remove MacPorts:
sudo port -dfp uninstall --follow-dependencies installed
sudo port -dfp uninstall all
sudo rm -rf /opt/local
sudo rm -rf /Library/Tcl/macports*
Do it in iPhoto.
Edit.Crop or type cOriginal, the second dimensionSave.I don't think "what you want" really exists - so I'll answer with alternate ways to get there that are less painful than just staying in Preview.
I have a regular flow with fixed aspect where I use a tool from a camera suite (probably obsolete - certainly dubious about talking to the camera anymore with updated systems) that does fixed crop, resize to fixed pixels, and export - then open in Preview and use its color adjust tools (which get where I want faster than things with more options, and well-enough for the job.) You may find something similar (crop-wise) in software for a camera you own.
If "the behemoth" (or lack thereof) is your main issue, GIMP does fixed aspect crop for an attractive price (free or what you choose to donate) and without (IMHO) being a behemoth. It's quietly become quite decent, though it started out laughably bad.
Draw a diagonal from one corner to the other. Then hit Cmd-A and move one of the corresponding corner handles on the line to mark your desired region. Hit crop and then delete the line again.
You might not consider this simpler than opening image editing software :) but it is quite fast nonetheless.
I love how everyone is saying there is no way... There is always a way, given not the best.
I know this thread is old but you could always do it with an Automator script.. You don't have control of what is cropped though...
If I understand your question correctly you could just use the Adjust Size… option from the Tools menu, and if it's not selected already, set Fit into to Custom.
