The Shape of Everything
A website mostly about Mac stuff, written by Gus Mueller
» Acorn
» Twitter
» Pizza Lab
» Code
» Archive
December 6, 2013

Acorn 4.2 is out, and this release is for the Pros.

Acorn has implemented some of the top feature requests from professional users

  • Opening a raw image with more than 8 bits per component (bpc) will pop Acorn into a 16 bpc "deep" workspace for image processing and saving. If you have a newer DSLR that takes wide gamut pictures- this is for you.
  • Acorn 4.2 also has an option to convert your image into a 16 bpc image. Wide gamut displays are becoming more popular and Acorn is ready for it.
  • Acorn’s default color profile is now set to sRGB.
  • The crop palette now has an option to keep the aspect ratio of your crop bounds when saving a new preset (this has been requested frequently in the past, so I'm happy to finally incorporate it).
  • There are now keyboard shortcuts for flipping through the various blend modes for a layer.
  • The upper boundary for brush diameters has been increased to 1600 pixels wide. Other image editors max out before that and still stutter when trying to draw with a giant brush on an 83 megapixel image[^1]. Acorn 4.2 handles this task with ease, and the reason is…

Acorn has been supercharged in anticipation of the new Mac Pros

Pixels get to the screen so much faster now that everything is drawn through OpenGL. Not only that, but Acorn takes advantage of OpenCL by virtue of using Core Image. Acorn also uses custom OpenCL kernels I hand coded to speed up other operations. Acorn incorporates some super fast algorithms combined with GCD to minimize the amount of drawing that happens. Less drawing means longer battery life and overall things go faster.

I had mentioned in a previous post that I was reworking the compositing engine. I'm not done with that yet, but the progress I have made is promising. So with a bit more work and time, things are going to get even faster for Acorn.

More awesome stuff in Acorn 4.2

I've also added some other new features such as "Radial Gradient Blur", which is sort of like a vignette but with a blur. It's fun, try it out!

There's a new Share menu item which will let you post your images to Flickr, Twitter, and Facebook, or send them to iPhoto and Aperture.

The pencil tool has been revamped with pixel editing in mind. You can now draw exact squares to help you make perfect pixel art. Acorn even allows you to set the pencil blend mode, including a new "Copy" blend mode that is exclusive to the Pencil tool.

You can now extend a selection after you've made it. Use the arrow keys when a selection is made (and one of the selection tools is active) and hold down the option key. Acorn will copy the selection in the direction you press with the keys, thus extending the selection by a pixel (or 10 if you hold down the shift key).

And there are many more improvements including bug fixes of course. You can read the full release notes for the gory details.

Other stuff

We'll be submitting Acorn 4.2 to the Mac App Store shortly. Even though 4.2 has been in beta for a while with lots of folks banging on it- I want to make sure it's absolutely solid before I submit it to Apple. It's a lot easier to get a quick bug fix out via direct downloads than the App Store. So look for it there soon.

Why are you still reading? Go grab Acorn 4.2 and take it for a spin. And if you have feedback- let us know.

OK, one last thing. We've got some new forums for Acorn up that we're beta testing. I thought it'd be fun to put up a post describing some of the technical changes in 4.2.

[^1]: Here's the image I've been testing with: Mona Lisa, by Leonardo da Vinci. It's a 7479 x 11146 pixel image weighing in at 89.94 MB. The main machine I've done my testing on is a Mid 2012 2.3 GHz Intel Core i7 Retina MPB with 16 GB ram, while viewing the image at 10%.