Fast RAW image viewer

[ghost]

I tend to take pictures in RAW format and it's always a pain whenever I just want to browse through them to take a look.
Pretty much every image viewer I've found for Windows has a noticeable lag of a few seconds to load one of those images, and even if the support going back on forth images in a folder they don't seem to cache recently seen photos. Every time you try to go back and forth you're hit by that lag.

What's even weirder is that you can't even get a simple thumbnail for the picture, even though these formats generally support a small version of the image compressed in something like JPG.

The situation is not much better on macOS. Quicklook takes several seconds as well to show you the image. The only reason you don't notice it with Preview is because it's slow to boot by default.

What I'd like:

• Something that opens images really fast for reasonably sized images (<100MB).
• Support navigating through pictures in the same directory using arrow keys.
• Support some generic RAW image format like DNG and allow for new formats to be added via plugins.

[bvisness]

Fast image viewers are a relatively common thing in the community, actually. @nakst has one called imgview; @d7samurai has one but I don't think he's publicly released it.

Depending on how nakst feels, contributions to imgview might be very welcome! I'd be curious to know what he thinks.

(By the way, being able to set up a simple slideshow from a folder would be very welcome. I had to do a photo slideshow recently, and it's actually impossible all the stock Windows stuff these days, as far as I can tell. The Windows photo viewer just crashed when we tried to do it. We had to use PowerPoint, import all the photos, and manually set up a timer on the slides...it was terrible.)

[nakst]

Actually, speed was not a goal for imgview (in fact, it uses GDI+ and is pretty slow with large images). The goal was to create something lightweight (it's 12 KB IIRC) but with a full set of user interactions that behave nicely (stuff like automatically fitting the image when shrinking the window, but not when you're zoomed in; browsing images in the same order as they appear in Explorer; etc.).
I think it would make a good base for a fork, but you'd have to rip out the old image displaying and loading code.

[mmozeiko]

To me it seems main topic of request is to have fast RAW image viewer. Not just image viewer. Writing "fast" image viewer is not a big deal, because there's not much happening in image viewer - just blit to screen with simple transformations (and whatever UI you want on top of it).

The problem is RAW images, not sure if their format are documented or all reverse engineered, afaik there are multiple variants out there, and it requires special processing on pixel level of loaded data before actually you're able to draw them. Pretty much most existing viewers just use libraw or similar library, that's why they are equally slow. So really, this is ask about writing fast RAW image loading code, not image viewer :)

[gingerBill]

I've pretty much written one of these already and it does the debayering, (post)processing, etc a few 1000 fps without much trouble.

The real issue as others have stated in here is not the viewer but the decoding. Each manufacturer does its own RAW nonsense. The vast majority of RAW files are just TIFF but the encoding is very weird and undocumented. Libraries such as libRaw are not brilliant but better than if you were trying to do it from scratch.

To make a RAW reader from scratch, it is definitely not possible to do it within a year, let alone a week-long jam.

[ghost]

I've pretty much written one of these already and it does the debayering, (post)processing, etc a few 1000 fps without much trouble.

Any chance you could share that? :D

The vast majority of RAW files are just TIFF but the encoding is very weird and undocumented

Yeah, that's why I listed DNG as there's decent documentation on it online. Not sure about other formats though.

[nkellum]

My brother is a photographer and has had the exact same experience! That's why I'm trying my hand at making a dng viewer to navigate through images quickly and sort them (right now just trying to get JPG images from the DNG files and displaying those, then down the line try to process raw). I'm using C/C++ with ImGui and OpenGL.

It's true that decoding and displaying raw images isn't simple, but hopefully I can get it to work with enough time.

[raysan5]

I created rTexViewer, it has RAW support but limited. In any case, it can be used as a reference. The RAW loader menu is included as one of the raygui examples.

[ghost]

@raysan5 is rTexViewer's code open? 🤔 It's a good reference in terms of functionality though!

[raysan5]

It's not open source at the moment but lately I open sourced some of the tools, maybe I open it at some moment. In any case, it uses all the functions provided by raylib, the tool is mostly a frontend for the functions, you can check LoadImageRaw() from raylib.