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出处：#include "cxcore.h"#include "highgui.h"#includeCvSeq* point_seq = 0;IplImage* canvas = 0;CvScalar* colors = 0;int pos = 10;int is_equal( const void* _a, const void* _b, void* userdata ){CvPoint a = *(const CvPoint*)_a;CvPoint b = *(const CvPoint*)_b;double threshold = *(double*)userdata;return (double)(a.x - b.x)*(a.x - b.x) + (double)(a.y - b.y)*(a.y - b.y) <= threshold;}void on_track( int pos ){CvSeq* labels = 0; //声明输出标签double threshold = pos*pos; //定义阈值为pos^2int i, class_count = cvSeqPartition( point_seq, 0, &labels, is_equal, &threshold );//对point_seq点序列拆分为等效的类，条件是(Ax-Bx)^2+(Ay-By)^2<=pos^2//含义为两点相差距离小于pos的属于一类printf("%4d classes/n", class_count );//打印出分了几类cvZero( canvas );for( i = 0; i < labels->total; i++ ){//取点、取颜色，画圆,你可以用按任意键的方式一个点一个点的画CvPoint pt = *(CvPoint*)cvGetSeqElem( point_seq, i );CvScalar color = colors[*(int*)cvGetSeqElem( labels, i )];cvCircle( canvas, pt, 1, color, -1 );cvShowImage( "points", canvas );cvWaitKey(0);}}int main( int argc, char** argv ){CvMemStorage* storage = cvCreateMemStorage(0);//建立了一个存储器point_seq = cvCreateSeq( CV_32SC2, sizeof(CvSeq), sizeof(CvPoint), storage );//建立了一个32位整型序列CvRNG rng = cvRNG(0xffffffff);//初始化随机数生成器int width = 500, height = 500;//定义图像的长和宽int i, count = 1000;//定义了两个计数器canvas = cvCreateImage( cvSize(width,height), 8, 3 );//设置图像，大小为500*500，色深8，三通道colors = (CvScalar*)cvAlloc( count*sizeof(colors[0]) );//分配1000个CvScalar大小的内存缓冲区for( i = 0; i < count; i++ ){CvPoint pt;//设置一个点int icolor;//定义颜色标的pt.x = cvRandInt( &rng ) % width;//随机产生点的x坐标pt.y = cvRandInt( &rng ) % height;//随机产生点的y坐标cvSeqPush( point_seq, &pt );//添加这个点到序列的尾部icolor = cvRandInt( &rng ) +0xa0a0a0a0 ;//用随机的方法给颜色标的一个基准，后边加的那个数字是可以任意的。colors[i] = CV_RGB(icolor & 255, (icolor >> 8)&255, (icolor >> 16)&255);//把这个点的颜色完全写入标量容器colors中}cvNamedWindow( "points", 1 );//创建窗口cvCreateTrackbar( "threshold", "points", &pos, 50, on_track );//建立拖动条，名称为threshold，窗口的名字叫points，创建初始化值取自pos，//回调函数名称为on_trackon_track(pos);//监视拖动条的改变并处理之cvWaitKey(0);return 0;}
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