使用指针数组复制PPM图像

Question

因此，我尝试编写一个程序，该程序将接收PPM图像并制作它的新副本。

我使用平面阵列来保存原始像素数据并使用fwrite写入新图像。但是，当试图使用“2-D”阵列来实现相同的结果但我不断得到一个seg。错误，我不知道如何解决它。

这些是我的课程：

ppmWriter.cc

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "ppmWriter.h"
int ppmWriter(const char *filename,int **array, int *width, int *height)
{
    const int max = *width**height*3;
    FILE * fp;

    fp = fopen(filename, "w");
    fprintf(fp, "P6\n%d %d\n255\n", *width, *height);
    unsigned char* rgb;
    int *newarray = new int[*width**height*3];
    int* flat = array[0];
    int nelements = *width**height;
    int index=0;
    for(int i=0; i<nelements; ++i) // loop for w*h times and each iteration fills in 3 slots-r,g,b- of the
    {
        rgb = (unsigned char*)(&(flat[i]));
        newarray[index++]=rgb[0];
        newarray[index++]=rgb[1];
        newarray[index++]=rgb[2];
    }
    fwrite( flat, sizeof(char),max,fp);

    fclose(fp);
    printf("OK - file %s saved\n", filename);
    return 0;
}

Main.cc

#include <cstdio>
#include <stdio.h>
#include "ppmWriter.h"
#include "ppmReader.h"

int main(int argc, char** argv)
{
    int width, height;
    int ** array = ppmReader("test.ppm",&width,&height);
    ppmWriter("test2.ppm", array , &width, &height);
}

ppmReader.cc

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "ppmReader.h"
int **ppmReader( const char *filename, int *width, int *height)
{
    FILE *fp = fopen(filename,"r");
    unsigned char *buff;
    int s,h,w;
    if (!fp) {
        fprintf(stderr, "Unable to open file '%s'\n", filename);
        exit(1);
    }
    fscanf(fp,"P6\n%d %d\n255\n", &w, &h);
    *width=w ;
    *height=h;
    s= h*w*3;
    buff= new unsigned char[s];
    fread(buff,sizeof(char),s,fp);
    fclose(fp);

// Initiates a Numerical Recepies Trick array ( pointer to a pointer to and int array, aka 2D array)
//-----------------------------------------------------------------------
    unsigned char* rgb;
    int** array = new int*[w];
    *array = new int[w*h];
    for(int j=1; j<h; ++j)
    {
        array[ j ] = array[ j-1] + w;

    }
//1-loop traversing through array
//-----------------------------------------------------------------------
    int* flat = array[0];
    int nelements = w*h;
    for(int i=0; i<nelements; ++i)
    {
        rgb = (unsigned char*)(&(flat[i]));
        rgb[i] = *(buff++);
        rgb[i+1] = *(buff++);
        rgb[i+2] = *(buff++);
        rgb[i+3] = 0;
    }

    return array;
}

头文件：

#ifndef ppmReader_h
#define ppmReader_h

#include <stdio.h>

int **ppmReader( const char *filename, int *width, int *height);

#endif /* ppmReader_h */

和

#ifndef ppmWriter_h
#define ppmWriter_h

#include <stdio.h>

int ppmWriter(const char *filename, int** array, int *width, int *height);

#endif /* ppmWriter_h */

我实际上是将数据分配到一个二维数组中，然后“尝试”恢复此过程并将其写入一个平面数组并将其写入图像。