如何用opencv实现jpg图片转换为pgm格式

[awful199baayng]

利用opencv实现jpg到pgm的抓换，C++也可以，只要是控制台程序

[C_amateur]

void cvConvertImage2pgm(char* filename,IplImage* srcImage,int type)
{
	int width=srcImage->width;
	int height=srcImage->height;

	FILE *pgmPict;
	int rSize=width*height;
	int i,j;
	pgmPict=fopen(filename,"w"); 
	if(type==2)
	{
		fprintf(pgmPict,"P2\n");
	}else if(type==5)
	{
		fprintf(pgmPict,"P5\n");
	}
	fprintf(pgmPict,"%d %d \n%d\n",width,height,255);
	if(type==5)
	{
		unsigned char temp=0;
		for( i=0;i<srcImage->height;i++)
		{
			for( j=0;j<srcImage->width;j++)
			{
				temp=srcImage->imageData[i*srcImage->widthStep+j*3];
				fwrite((void*)&temp,sizeof(unsigned char),1,pgmPict);
			}
		}
	}
	else if(type==2)
	{
		for( i=0;i<srcImage->height;i++)
		{
			for( j=0;j<srcImage->width;j++)
			{
				int temp=(int)srcImage->imageData[i*srcImage->widthStep+j*3];
				if(temp<0)
					temp+=256;
				fprintf(pgmPict,"%d ",temp);
			}
		}
	}
	fclose(pgmPict);
}