BoofCV VS JDK

BoofCV https://github.com/lessthanoptimal/BoofCV

Is there any fast way to get pixel values and pixel coordinate? I had to jump through a lot of hoops to get convert BufferedImages into a format that's useful for image processing it to be a reasonable speed in BoofCV. getRGB() is glacial. At one point I was trying to convince the JDK team to make private data structures public again. Right now it's inconsistent what you have access too.

Apologizes if this post runs afoul of the rules. This is a product we are making that started as an open source project (here).

I will take the opportunity to call out one of my favourite libraries, BoofCV (http://boofcv.org)

It comes with a wonderful demonstration tool that allows you to apply the various included algorithms to images and tweak the parameters in real-time – including the Hough transform. A great tool for helping to understand how these kinds of algorithms work!

Speaking of using the vector api, I see there's a class in boofcv that converts rgb to hsv. I've previously written a simd accelerated version of rgb to hsv using the java vector api. For anybody looking to do a bit of code janitor work, converting the one-off library into something that could be contributed to /u/lessthanoptimal's project might be a worthwhile contribution.

For instance I looked at BoofCV and all I found was : https://github.com/lessthanoptimal/BoofCV/issues/265 " the question now seems to be can you compile the library as native. The answer is probably but someone needs to try it."

It's an all-Java computer vision library, see https://boofcv.org/ and https://github.com/lessthanoptimal/BoofCV

project website: https://boofcv.org

There really is a community for everything on Reddit... Anyways, so I've updated the tutorial on QR Codes in BoofCV. If you're not familiar with it, BoofCV is a computer vision library that also includes a high quality QR Code scanner. Plenty of benchmarks and examples can be found on the website to back that up. Here's a link to the tutorial page and please let me know if it all makes sense. The tutorial focuses on applications which are either command line or have a GUI.

I felt out of the loop, thinking that Zero VM was some kind of new distro for OpenJDK but chasing <https://packages.debian.org/sid/openjdk-22-jre-zero#:~:text=...> to <https://sources.debian.org/src/openjdk-11/11.0.23%2B9-1/debi...> lead me to https://github.com/openjdk/jdk/tree/jdk-22-ga/src/hotspot/cp...

It seems that it's a specific CPU target for the Hotspot JIT for non-mainstream architectures (or for research purposes, as I saw mentioned once)

Completely gutted from the OpenJDK, last I checked. See here for the culprit PR: https://github.com/openjdk/jdk/pull/18688

> Yes, they're changing one aspect of signal handler use to work around this problem. They're not stopping the use of signal handlers in general. Hotspot continues to use signals for efficiency in general. See https://github.com/openjdk/jdk/blob/9059727df135dc90311bd476...

This whole thread is about SIGSEGV, and specifically their SIGSEGV handling. However, catching normal signals is not about efficiency.

Some of their exception handling is still odd: There is no reason for a program that receives SIGILL to ever attempt continuing. But others is fine, like catching SIGFPE to just forward an exception to the calling code.

(Sure, you could construct an argument to say that this is for efficiency if you considered the alternative to be implementing floating point in software so that all exceptions exist in user-space, but hardware floating point is the norm and such alternative would be wholly unreasonable.)

> The wonderful thing about choosing not to care about facts is having whatever opinions you want.

I appreciate the irony of you making such statement, proudly thinking that your opinion equals fact, and therefore any other opinion is not.

This discussion is nothing but subjective opinion vs. subjective opinion. Facts are (hopefully, as I can only speak for myself) inputs to both our opinions, but no opinion about "good" or "bad", "nasty" or not can ever be objective. Objective code quality does not exist.

I remember talking to Brendan about the PreserveFramePointer patch during my first months at Netflix in 2015. As of JDK 21, unfortunately it is no longer a general purpose solution for the JVM, because it prevents a fast path being taken for stack thawing for virtual threads: https://github.com/openjdk/jdk/blob/d32ce65781c1d7815a69ceac...