《学习OpenCV》课后习题解答7

题目：（P105）

创建一个结构，结构中包含一个整数，一个CvPoint和一个 CvRect；称结构体为“my_struct”。

a. 写两个函数：void Write_my_strct(CvFileStorage* fs, const char * name, my_struct* ms) 和 void read_my_struct(CvFileStorage* fs, CvFileNode* ms_node, my_struct* ms)

b. 创建一个元素为my_struct结构体且长度为10的数组，并将数组写入磁盘和从磁盘读入内存。

解答：

#include<cv.h>
#include<highgui.h>

typedef struct my_struct {
    int integer;
    CvPoint ptr;
    CvRect rect;
}my_struct;

void write_my_struct(CvFileStorage* fs, const char* name, my_struct* ms) {
    cvWriteInt(fs, "integer", ms[0].integer);

    cvStartWriteStruct(fs, "ptr", CV_NODE_SEQ);
    cvWriteInt(fs, NULL, ms[0].ptr.x);
    cvWriteInt(fs, NULL, ms[0].ptr.y);
    cvEndWriteStruct(fs);

    cvStartWriteStruct(fs, "rect", CV_NODE_SEQ);
    cvWriteInt(fs, NULL, ms[0].rect.x);
    cvWriteInt(fs, NULL, ms[0].rect.y);
    cvWriteInt(fs, NULL, ms[0].rect.width);
    cvWriteInt(fs, NULL, ms[0].rect.height);
    cvEndWriteStruct(fs);
}

void read_my_struct(CvFileStorage* fs, CvFileNode* ms_node, my_struct* ms) {
    int integer = cvReadIntByName(fs, NULL, "integer", 5);
    CvSeq* seq = cvGetFileNodeByName(fs, NULL, "ptr")->data.seq;
    int ptr_x = cvReadInt((CvFileNode*)cvGetSeqElem(seq, 0));
    int ptr_y = cvReadInt((CvFileNode*)cvGetSeqElem(seq, 1));
    seq = cvGetFileNodeByName(fs, NULL, "rect")->data.seq;
    int rect_x = cvReadInt((CvFileNode*)cvGetSeqElem(seq, 0));
    int rect_y = cvReadInt((CvFileNode*)cvGetSeqElem(seq, 1));
    int rect_width = cvReadInt((CvFileNode*)cvGetSeqElem(seq, 2));
    int rect_height = cvReadInt((CvFileNode*)cvGetSeqElem(seq, 3));
    CvPoint ptr = cvPoint(ptr_x, ptr_y);
    CvRect rect = cvRect(rect_x, rect_y, rect_width, rect_height);
    ms->integer = integer;
    ms->ptr.x = ptr_x;
    ms->ptr.y = ptr_y;
    ms->rect.x = rect_x;
    ms->rect.y = rect_y;
    ms->rect.width = rect_width;
    ms->rect.height = rect_height;
}

int main(int argc, char** argv) {
    my_struct ms[10] = { { 10, cvPoint(5, 5), cvRect(5, 5, 10, 10) } };
    CvFileStorage* sfs = cvOpenFileStorage("E:\\cfg.xml", NULL, CV_STORAGE_WRITE);
    write_my_struct(sfs, "struct", ms);
    cvReleaseFileStorage(&sfs);

    my_struct* ms2 = (my_struct*)malloc(sizeof(my_struct));
    CvFileStorage* ofs = cvOpenFileStorage("E:\\cfg.xml", NULL, CV_STORAGE_READ);
    read_my_struct(ofs, NULL, ms2);
    cvReleaseFileStorage(&ofs);

    printf("integer: %d\n", ms2->integer);
    printf("ptr: (%d, %d) \n", ms->ptr.x, ms->ptr.y);
    printf("rect: (%d, %d, %d, %d) \n", ms->rect.x, ms->rect.y, ms->rect.width, ms->rect.height);
    getchar();
    return 0;
}