Re: 1x, 2x, 3x and so on graphics.

Dave Fernandes

DPI tells it how big to print on paper. It is the number of pixels that matter for the screen asset. 90x90 pixels is 3x higher resolution than 30x30 pixels no matter what DPI values are in the metadata.

On Oct 10, 2018, at 8:39 PM, Alex Zavatone via Groups.Io <zav@...> wrote:

I’ve been recooking up my tools and decided to take another stab at graphic fidelity when preparing graphics for iOS, Android and Mac apps.

Previous tests I did in the past indicated that creating graphics at the same dimensions (say 30x30) but increasing the DPI in Preview created assets that do look good on higher density devices using a DPI of 72, 144, and 216 when compared to making png images at 1x, 2x and 3x in dimensions in Preview or Photoshop.

Attempting to use PDF images, they look fuzzy and like crap on the Mac, but good on all devices.

This time, I’m using Apple’s sips.

One thing that seems odd is that when using either sips or Preview, changing the DPI of the image for 1x, 2x and 3x images seems to ignore the DPI when combined with the pixels of the image. I’d expect a 30 x 30 image at 30x30 to be a 3x image, but this is not the case. A basic PNG at 90x90 looks perfect when compared to a 30x30 PNG at a 216 DPI, which looks just as bad (fuzzy) as a 30x30 PNG at 72 DPI.

Is this expected?

Alex Zavatone

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