r/foss • u/mcebrianeriond • 3d ago

[FOSS] Pictty - Clean, fast, accurate picture viewer for MacOS

Why?
I wanted to create the fastest, cleanest-rendering Mac image viewer.

It is ready for prime time. Pictty is free, GPL-3.0, for macOS 15 and later.

One-minute video

https://reddit.com/link/1x949c1/video/ooa4u19zg8wh1/player

The rendering is why it exists. While you pan or zoom, the GPU moves the picture at the display's full refresh rate. Pictty redraws the visible region with Lanczos-3 at one picture pixel per screen pixel. Shrinking happens in linear light. Most viewers average the stored values, which sit on a gamma curve, so fine detail like foliage, hair, stars or small text comes out darker than it really is. A black-and-white checkerboard should shrink to the grey of real light, and in Pictty it does.

Linear light. A file stores brightness on a curve, not as amounts of light. Averaging those stored numbers, as most viewers do when they shrink a picture, makes fine detail darker than it is: foliage, stars, hair and text go dull. Pictty turns the numbers back into real light first, averages, and only then converts back.

In Best Fit the window takes the shape of the picture, and on macOS 26 the toolbar and filmstrip are Liquid Glass and get out of the way when you stop moving the pointer:

UI disappears when not required

Synced Pan-Zoom picture comparison (4 modes):

100% Keyboard friendly

The rest:

  • High-quality preview first: a preview made for your screen with the best algorithms, turning seamlessly into the full-resolution picture when the zoom needs it.
  • Pixel-exact at rest: when the picture rests, the visible region is redrawn with Lanczos at one picture pixel per screen pixel, placed to a tenth of a pixel.
  • Linear-light shrinking: reductions average real light, not the stored numbers, so fine detail keeps its brightness.
  • Clean enlarging: up to 300 % with Lanczos; beyond that, smooth GPU filtering.
  • Full refresh rate in motion: the GPU moves, zooms and rotates the picture through Core Animation, on whole device pixels.
  • Real RAW: Apple's RAW engine develops every camera file; the camera's embedded preview shows at once.
  • True HDR: gain maps, PQ and HLG with extended dynamic range and the display's live headroom.
  • Giant pictures: every pixel past the GPU's 16,384-pixel texture limit, at 100 % and beyond.
  • Formats: JPEG, HEIC, AVIF, JPEG XL, WebP, PNG, TIFF, GIF (animated), BMP, OpenEXR, PSD, TGA, SVG and RAW from hundreds of cameras.
  • Pixel loupe with RGB values and the hex colour; ⌥-click copies it.
  • Histogram and clipping warnings: blown highlights in red, blocked shadows in blue.
  • Information panel: camera, lens, exposure, size, colour profile, dates, location and provenance.
  • Compare up to four pictures: side by side, stacked, grid, wipe and blink, with synced pan and zoom.
  • Five zoom modes: Actual Size, Best Fit, Fit to Window, Remember Zoom, and Lock Zoom & Window.
  • Filmstrip, slideshow, rotate, mirror, copy, reveal in Finder, move to Trash.
  • Multiple windows, one per folder, chosen automatically when you open pictures from Finder.
  • Default viewer: Pictty can open your pictures on a double-click in Finder.
  • Liquid Glass toolbar, filmstrip, pills and panels on macOS 26 and later.
  • English and Spanish, and a key for every action.
  • Private: no account, no analytics, no network connections.

Download: https://www.noxdrop.com/pictty.html

Source: https://github.com/marcocebrian/Pictty

It's 1.0, so I'd like to hear what breaks, especially with odd files.

4 Upvotes

100% Upvoted

4 comments sorted by

3

u/rikyulink 3d ago

Great. I decide to replace Picview with Pictty. Nice UI. Great performance.

2

u/mcebrianeriond 3d ago

Thank you!

2

u/investigatormaker 3d ago

The linear-light shrinking is the part people can check for themselves, so a downloadable test image (the black-and-white checkerboard next to a fine foliage crop) would let anyone compare Pictty with Preview side by side. Odd files worth trying: CMYK JPEGs with an embedded profile, EXIF orientations 5 to 8 (the transposed ones), 16-bit PNGs with a gamma chunk and no ICC profile, and animated WebP or AVIF, since the list mentions animation only for GIF.

I make ThreadFox. For Mac users and photographers asking which image viewer to use, our AI employee will post 3 helpful replies explaining Pictty in those Reddit threads for you, free, no card. https://threadfox.vip/p/eqp41/managed

1

u/mcebrianeriond 3d ago

Thanks for the comment. Everything you mentioned should be covered. Tested 16bits png and many edr combos I could find. Animated Webp, no problem.