Sort array in filterContours

[SamCarlberg]

FWIW you could also write that as

public static void sortContoursByArea(List<MatOfPoint> contours) {
  Collections.sort(contours, Comparator.comparingDouble(Imgproc::contourArea));
}

[PhilBot]

Originally Posted by SamCarlberg

FWIW you could also write that as

public static void sortContoursByArea(List<MatOfPoint> contours) {
  Collections.sort(contours, Comparator.comparingDouble(Imgproc::contourArea));
}

That's a really interesting syntax.

Is there a name for what is hapening with "Imgproc::contourArea" ?
I'd like to look up the explanation of how that works...

Clearly it's getting expanded internally into Imgprog.contourArea(contours[n]) for the comparison.... but I don't know how/why.....

[SamCarlberg]

That's called a method reference.

This article explains it quite well

Also, you don't even need a special method for sorting a list. The List interface defines a method "sort(Comparator)" that you can use inline like

contours.sort(Comparator.comparingDouble(Imgproc::contourArea));

[PhilBot]

Originally Posted by SamCarlberg

That's called a method reference.

This article explains it quite well

Also, you don't even need a special method for sorting a list. The List interface defines a method "sort(Comparator)" that you can use inline like

contours.sort(Comparator.comparingDouble(Imgproc::contourArea));

Dang... As an "vintage" programmer, it's sometimes scary when I realize how much I don't know about the "newer" languages. That's pretty darn powerful.