A Better Algorithm For Scaling

When something is scaled in Photoshop, chances are you’ll get aliasing artifacts and an overall reduction in quality. This is particularly noticeable when what you are scaling has high contrast areas (shadows and highlights close to each other). The issue becomes even more pronounced when dealing with a canvas with a transparent background. In short: A template like the OS X one is extra prone to the sort of aliasing issues automatic scaling creates. For the longest time this unavoidable fact has kept me from releasing a resource I knew thousands of people would rely on.

With the tools at our disposal, we'll never quite be able to get rid of the issues related to scaling, but to somewhat combat this in this highly susceptible template, I've come up with a new export scheme. In my previous templates the export actions would slice up each scaled smart object and export each individual slice. With that method, Photoshop defaults to automatic bicupic scaling. (This is the same thing that happens when you just transform something in Photoshop). The algorithm Photoshop uses when downsizing has sharpening qualities which might work fine if you're working with pictures, but not when you're working with hairline contrasts. The result of this automatic scaling is noticeable aliasing issues.

Now, instead of saving out each of the sliced sizes you see in the template, the new export action will resample the largest icon with a plain bicupic algorithm (with less sharpening qualities). It will do this repeatedly for each size. What this means is that the multiple sizes you’re seeing auto generated via smart objects in the template is just a preview and not part of the actual export. A lot of people will surely comment on this so let me repeat; the smaller sizes in the template is just there as a preview, they'll suffer from the usual issues related to automatic scaling. The actual outputted files should look better.

(If your email client in complete irony botched the example image on the right, check out this bigger view)