@Override
@SuppressWarnings("unchecked")
public void perform(InputSocket<?>[] inputs, OutputSocket<?>[] outputs, Optional<?> data) {
final Mat input = ((InputSocket<Mat>) inputs[0]).getValue().get();
final Mat tmp = ((Optional<Mat>) data).get();
final boolean externalOnly = ((InputSocket<Boolean>) inputs[1]).getValue().get();
if (input.empty()) {
return;
}
// findContours modifies its input, so we pass it a temporary copy of the input image
input.copyTo(tmp);
// OpenCV has a few different things it can return from findContours, but for now we only use
// EXTERNAL and LIST.
// The other ones involve hierarchies of contours, which might be useful in some situations, but
// probably only
// when processing the contours manually in code (so, not in a graphical pipeline).
MatVector contours = new MatVector();
findContours(
tmp, contours, externalOnly ? CV_RETR_EXTERNAL : CV_RETR_LIST, CV_CHAIN_APPROX_TC89_KCOS);
final OutputSocket<ContoursReport> contoursSocket = (OutputSocket<ContoursReport>) outputs[0];
contoursSocket.setValue(new ContoursReport(contours, input.rows(), input.cols()));
}
