Update Jan 2019: Adobe has still not addressed this issue, although I made suggestions that solve the problem indirectly without even having to modify any GPU code:
- should scale only to a supported GPU scaling factor instead of blindly fitting exactly to the window. Why not? It’s already buggy in adding excessive margin space around the image.
- Letting the user define desired scaling factor(s) so that uses that scaling for a clean rendition. Why are things hard-coded as they are?
- Just let the user redefine the cmd-0 shortcut to scale to some desired factor: 50%, 33%, 25% — and make darn sure the GPU has a high quality version at that scaling factor.
Back in November 2014 I reported on blurry image scaling in Photoshop with the GPU enabled. This issue has not been addressed even here in November 2015.
For my work in assessing images, I must be able to see a non-blurred image atwhen I evaluate my images in Photoshop CC 2015. Because of this bug, I am forced to disable the GPU. Which mean impaired performance for a variety of operations.
Specifically, Fit to Screen on a 2560 X 1600 display results in a blurry image with large digital files. This makes it impossible to assess batches of images without a time-wasting zoom in/zoom out hassle. And it is not a pleasure to look at a blurred image, if not an outright eyestrain.
Photoshop allows enabling or disabling GPU support in.
Different cache levels and GPU settings are all broken. GPU support is just plain broken for zooming in Photoshop; some zoom levels are sharp and others are awful. Actual pixels is fine of course, but then one cannot see the image as a whole. Surely a fast GPU can render a reduced size image far better than is being done (dual GPUs in Mac Pro!). But I’m told by Adobe that fixing this is not easy. But since when is such a damaging bug acceptable for three years in an image editor?
Note that the GPU blur depends on the amount of zoom relative to screen and image size, so a different size image or display might be fine for some users. And indeed some zoom levels are reasonably sharp—but neverwith my typical images.
I reported this to Adobe over three years ago, but nothing has been done.
Update: in a frustrating twist for my work, support for 10-bit color requires that GPU support be enabled. So I get blurry images and 10-bit color, or sharp images and 8-bit color.
The image below is a crop of the whole. Observe the blur with GPU enabled and sharp image with the GPU disabled (toggle). Click for a full size image.