这里定义一个函数ecvOutputMatrix，用于打印CvMat的元素。下面有两个例子。
例一在Debug时有误，而在Release时没有问题，这由CV_MAT_ELEM的定义可见，其中有assert表达式，使得CV_MAT_ELEM在Debug情况下只能应用于单通道矩阵，实际上在Release情况下CV_MAT_ELEM还是可以应用于多通道矩阵的。
鉴于CV_MAT_ELEM的缺点，在例二中仿照CV_MAT_ELEM定义了三个宏，分别用于访问二三四通道矩阵中的元素。注意所定义的宏并没有保证row，col和cha小于矩阵的行数，列数和通道数，读者可以自行添加相应的assert表达式。
例一
#define CV_MAT_ELEM_2(mat,type,row,col,cha) (((type*)((mat).data.ptr+row*(mat).step))[2*col+cha])
#define CV_MAT_ELEM_3(mat,type,row,col,cha) (((type*)((mat).data.ptr+row*(mat).step))[3*col+cha])
#define CV_MAT_ELEM_4(mat,type,row,col,cha) (((type*)((mat).data.ptr+row*(mat).step))[4*col+cha])#include <cv.h>
#include <stdio.h>
#pragma comment( lib, "cv.lib" )
#pragma comment( lib, "cxcore.lib" )
void ecvOutputMatrix(CvMat *mat)
{
for(int i=0;i<mat->rows;i++)
{
for(int j=0;j<mat->cols;j++)
{
int type=cvGetElemType(mat);
switch(type)
{
case CV_8UC1:
printf("%d\t",CV_MAT_ELEM(*mat,uchar,i,j));
break;
case CV_8UC2:
printf("(%d,%d)\t",CV_MAT_ELEM(*mat,uchar,i,j*2),
CV_MAT_ELEM(*mat,uchar,i,j*2+1));
break;
case CV_8UC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM(*mat,uchar,i,j*3),
CV_MAT_ELEM(*mat,uchar,i,j*3+1),
CV_MAT_ELEM(*mat,uchar,i,j*3+2));
break;
case CV_8UC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM(*mat,uchar,i,j*4),
CV_MAT_ELEM(*mat,uchar,i,j*4+1),
CV_MAT_ELEM(*mat,uchar,i,j*4+2),
CV_MAT_ELEM(*mat,uchar,i,j*4+3));
break;case CV_8SC1:
printf("%d\t",CV_MAT_ELEM(*mat,signed char,i,j));
break;
case CV_8SC2:
printf("(%d,%d)\t",CV_MAT_ELEM(*mat,signed char,i,j*2),
CV_MAT_ELEM(*mat,signed char,i,j*2+1));
break;
case CV_8SC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM(*mat,signed char,i,j*3),
CV_MAT_ELEM(*mat,signed char,i,j*3+1),
CV_MAT_ELEM(*mat,signed char,i,j*3+2));
break;
case CV_8SC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM(*mat,signed char,i,j*4),
CV_MAT_ELEM(*mat,signed char,i,j*4+1),
CV_MAT_ELEM(*mat,signed char,i,j*4+2),
CV_MAT_ELEM(*mat,signed char,i,j*4+3));
break;case CV_16UC1:
printf("%d\t",CV_MAT_ELEM(*mat,unsigned short,i,j));
break;
case CV_16UC2:
printf("(%d,%d)\t",CV_MAT_ELEM(*mat,unsigned short,i,j*2),
CV_MAT_ELEM(*mat,unsigned short,i,j*2+1));
break;
case CV_16UC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM(*mat,unsigned short,i,j*3),
CV_MAT_ELEM(*mat,unsigned short,i,j*3+1),
CV_MAT_ELEM(*mat,unsigned short,i,j*3+2));
break;
case CV_16UC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM(*mat,unsigned short,i,j*4),
CV_MAT_ELEM(*mat,unsigned short,i,j*4+1),
CV_MAT_ELEM(*mat,unsigned short,i,j*4+2),
CV_MAT_ELEM(*mat,unsigned short,i,j*4+3));
break;case CV_16SC1:
printf("%d\t",CV_MAT_ELEM(*mat,short,i,j));
break;
case CV_16SC2:
printf("(%d,%d)\t",CV_MAT_ELEM(*mat,short,i,j*2),
CV_MAT_ELEM(*mat,short,i,j*2+1));
break;
case CV_16SC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM(*mat,short,i,j*3),
CV_MAT_ELEM(*mat,short,i,j*3+1),
CV_MAT_ELEM(*mat,short,i,j*3+2));
break;
case CV_16SC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM(*mat,short,i,j*4),
CV_MAT_ELEM(*mat,short,i,j*4+1),
CV_MAT_ELEM(*mat,short,i,j*4+2),
CV_MAT_ELEM(*mat,short,i,j*4+3));
break;case CV_32SC1:
printf("%d\t",CV_MAT_ELEM(*mat,int,i,j));
break;
case CV_32SC2:
printf("(%d,%d)\t",CV_MAT_ELEM(*mat,int,i,j*2),
CV_MAT_ELEM(*mat,int,i,j*2+1));
break;
case CV_32SC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM(*mat,int,i,j*3),
CV_MAT_ELEM(*mat,int,i,j*3+1),
CV_MAT_ELEM(*mat,int,i,j*3+2));
break;
case CV_32SC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM(*mat,int,i,j*4),
CV_MAT_ELEM(*mat,int,i,j*4+1),
CV_MAT_ELEM(*mat,int,i,j*4+2),
CV_MAT_ELEM(*mat,int,i,j*4+3));
break;case CV_32FC1:
printf("%lf\t",CV_MAT_ELEM(*mat,float,i,j));
break;
case CV_32FC2:
printf("(%d,%d)\t",CV_MAT_ELEM(*mat,float,i,j*2),
CV_MAT_ELEM(*mat,float,i,j*2+1));
break;
case CV_32FC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM(*mat,float,i,j*3),
CV_MAT_ELEM(*mat,float,i,j*3+1),
CV_MAT_ELEM(*mat,float,i,j*3+2));
break;
case CV_32FC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM(*mat,float,i,j*4),
CV_MAT_ELEM(*mat,float,i,j*4+1),
CV_MAT_ELEM(*mat,float,i,j*4+2),
CV_MAT_ELEM(*mat,float,i,j*4+3));
break;case CV_64FC1:
printf("%lf\t",CV_MAT_ELEM(*mat,double,i,j));
break;
case CV_64FC2:
printf("(%d,%d)\t",CV_MAT_ELEM(*mat,double,i,j*2),
CV_MAT_ELEM(*mat,double,i,j*2+1));
break;
case CV_64FC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM(*mat,double,i,j*3),
CV_MAT_ELEM(*mat,double,i,j*3+1),
CV_MAT_ELEM(*mat,double,i,j*3+2));
break;
case CV_64FC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM(*mat,double,i,j*4),
CV_MAT_ELEM(*mat,double,i,j*4+1),
CV_MAT_ELEM(*mat,double,i,j*4+2),
CV_MAT_ELEM(*mat,double,i,j*4+3));
break;
}
}
putchar('\n');
}
}
int main()
{
int m[]={
255, 255, 255,
255, 255, 255,
128, 200,1
};CvMat M=cvMat(1,3,CV_32SC3,m);
ecvOutputMatrix(&M);
cvReleaseData(&M);return 0;
}
例二
#include <cv.h>
#include <stdio.h>
#include <highgui.h>#pragma comment( lib, "cv.lib" )
#pragma comment( lib, "cxcore.lib" )
#pragma comment( lib, "highgui.lib" )#define CV_MAT_ELEM_2(mat,type,row,col,cha) (((type*)((mat).data.ptr+row*(mat).step))[2*col+cha])
#define CV_MAT_ELEM_3(mat,type,row,col,cha) (((type*)((mat).data.ptr+row*(mat).step))[3*col+cha])
#define CV_MAT_ELEM_4(mat,type,row,col,cha) (((type*)((mat).data.ptr+row*(mat).step))[4*col+cha])void ecvOutputMatrix(CvMat *mat)
{
for(int i=0;i<mat->rows;i++)
{
for(int j=0;j<mat->cols;j++)
{
int type=cvGetElemType(mat);
switch(type)
{
case CV_8UC1:
printf("%d\t",CV_MAT_ELEM(*mat,uchar,i,j));
break;
case CV_8UC2:
printf("(%d,%d)\t",CV_MAT_ELEM_2(*mat,uchar,i,j,0),
CV_MAT_ELEM_2(*mat,uchar,i,j,1));
break;
case CV_8UC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM_3(*mat,uchar,i,j,0),
CV_MAT_ELEM_3(*mat,uchar,i,j,1),
CV_MAT_ELEM_3(*mat,uchar,i,j,2));
break;
case CV_8UC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM_4(*mat,uchar,i,j,0),
CV_MAT_ELEM_4(*mat,uchar,i,j,1),
CV_MAT_ELEM_4(*mat,uchar,i,j,2),
CV_MAT_ELEM_4(*mat,uchar,i,j,3));
break;case CV_8SC1:
printf("%d\t",CV_MAT_ELEM(*mat,signed char,i,j));
break;
case CV_8SC2:
printf("(%d,%d)\t",CV_MAT_ELEM_2(*mat,signed char,i,j,0),
CV_MAT_ELEM_2(*mat,signed char,i,j,1));
break;
case CV_8SC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM_3(*mat,signed char,i,j,0),
CV_MAT_ELEM_3(*mat,signed char,i,j,1),
CV_MAT_ELEM_3(*mat,signed char,i,j,2));
break;
case CV_8SC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM_4(*mat,signed char,i,j,0),
CV_MAT_ELEM_4(*mat,signed char,i,j,1),
CV_MAT_ELEM_4(*mat,signed char,i,j,2),
CV_MAT_ELEM_4(*mat,signed char,i,j,3));
break;case CV_16UC1:
printf("%d\t",CV_MAT_ELEM(*mat,unsigned short,i,j));
break;
case CV_16UC2:
printf("(%d,%d)\t",CV_MAT_ELEM_2(*mat,unsigned short,i,j,0),
CV_MAT_ELEM_2(*mat,unsigned short,i,j,1));
break;
case CV_16UC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM_3(*mat,unsigned short,i,j,0),
CV_MAT_ELEM_3(*mat,unsigned short,i,j,1),
CV_MAT_ELEM_3(*mat,unsigned short,i,j,2));
break;
case CV_16UC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM_4(*mat,unsigned short,i,j,0),
CV_MAT_ELEM_4(*mat,unsigned short,i,j,1),
CV_MAT_ELEM_4(*mat,unsigned short,i,j,2),
CV_MAT_ELEM_4(*mat,unsigned short,i,j,3));
break;case CV_16SC1:
printf("%d\t",CV_MAT_ELEM(*mat,short,i,j));
break;
case CV_16SC2:
printf("(%d,%d)\t",CV_MAT_ELEM_2(*mat,short,i,j,0),
CV_MAT_ELEM_2(*mat,short,i,j,1));
break;
case CV_16SC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM_3(*mat,short,i,j,0),
CV_MAT_ELEM_3(*mat,short,i,j,1),
CV_MAT_ELEM_3(*mat,short,i,j,2));
break;
case CV_16SC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM_4(*mat,short,i,j,0),
CV_MAT_ELEM_4(*mat,short,i,j,1),
CV_MAT_ELEM_4(*mat,short,i,j,2),
CV_MAT_ELEM_4(*mat,short,i,j,3));
break;case CV_32SC1:
printf("%d\t",CV_MAT_ELEM(*mat,int,i,j));
break;
case CV_32SC2:
printf("(%d,%d)\t",CV_MAT_ELEM_2(*mat,int,i,j,0),
CV_MAT_ELEM_2(*mat,int,i,j,1));
break;
case CV_32SC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM_3(*mat,int,i,j,0),
CV_MAT_ELEM_3(*mat,int,i,j,1),
CV_MAT_ELEM_3(*mat,int,i,j,2));
break;
case CV_32SC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM_4(*mat,int,i,j,0),
CV_MAT_ELEM_4(*mat,int,i,j,1),
CV_MAT_ELEM_4(*mat,int,i,j,2),
CV_MAT_ELEM_4(*mat,int,i,j,3));
break;case CV_32FC1:
printf("%lf\t",CV_MAT_ELEM(*mat,float,i,j));
break;
case CV_32FC2:
printf("(%d,%d)\t",CV_MAT_ELEM_2(*mat,float,i,j,0),
CV_MAT_ELEM_2(*mat,float,i,j,1));
break;
case CV_32FC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM_3(*mat,float,i,j,0),
CV_MAT_ELEM_3(*mat,float,i,j,1),
CV_MAT_ELEM_3(*mat,float,i,j,2));
break;
case CV_32FC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM_4(*mat,float,i,j,0),
CV_MAT_ELEM_4(*mat,float,i,j,1),
CV_MAT_ELEM_4(*mat,float,i,j,2),
CV_MAT_ELEM_4(*mat,float,i,j,3));
break;case CV_64FC1:
printf("%lf\t",CV_MAT_ELEM(*mat,double,i,j));
break;
case CV_64FC2:
printf("(%d,%d)\t",CV_MAT_ELEM_2(*mat,double,i,j,0),
CV_MAT_ELEM_2(*mat,double,i,j,1));
break;
case CV_64FC3:
printf("(%d,%d,%d)\t",CV_MAT_ELEM_3(*mat,double,i,j,0),
CV_MAT_ELEM_3(*mat,double,i,j,1),
CV_MAT_ELEM_3(*mat,double,i,j,2));
break;
case CV_64FC4:
printf("(%d,%d,%d,%d)\t",CV_MAT_ELEM_4(*mat,double,i,j,0),
CV_MAT_ELEM_4(*mat,double,i,j,1),
CV_MAT_ELEM_4(*mat,double,i,j,2),
CV_MAT_ELEM_4(*mat,double,i,j,3));
break;
}
}
putchar('\n');
}
}
int main()
{
int m[]={
255, 255, 255,
255, 255, 255,
128, 200,1
};CvMat M=cvMat(1,3,CV_32SC3,m);
ecvOutputMatrix(&M);
cvReleaseData(&M);IplImage *image=cvLoadImage("lena.jpg",-1);
CvMat mat;
cvGetMat(image,&mat);
ecvOutputMatrix(&mat);
cvReleaseImage(&image);return 0;
}