Trying to sort ROI rectangles from left to right.
auto compare = [](const void* p1, const void* p2) -> int
{
const int* p1x = &(((const cv::Rect*)p1)->width);
const int* p2x = &(((const cv::Rect*)p2)->width);
return (*p2x) - (*p1x);
};
qsort(&vec, vec.size(), sizeof(cv::Rect), compare);
But ->width gives the wrong values.
your compare function is broken. also please use std::sort, not the c-style qsort.
int compare(const Rect &a, const Rect &b) {
return a.x - b.x;
}
std::sort(vec.begin(), vec.end(), compare);
I try this:
auto compare = [](const cv::Rect &a, const cv::Rect &b) -> int
{
a.x - b.x;
};
std::sort(empty_and_right_props.begin(), empty_and_right_props.end(), compare);
But no matters if I change to b.x - a.x it always sort reversed against original no sorted order.
Then after some iterations this function I don't know how falls into an infinite loop.
Broke my head :) Forgot about return :)
About app crash: now I change the comparator from int to bool and crash is gone.
auto compare = [](const cv::Rect &a, const cv::Rect &b) -> bool
{
return a.x > b.x; //left to right
};
std::sort(empty_and_right_props.begin(), empty_and_right_props.end(), compare);
Asked: 2018-07-29 23:23:45 -0600
Seen: 2,166 times
Last updated: Jul 29 '18