c - PPM 图像格式，高度和宽度不显示 - C

Question

我的程序旨在读取和显示 PPM 图像，但不会打印正在读取的图像的实际格式或高度或宽度。这可能是一个非常基本的错误，但我使用 C 的时间并不长。

编辑:我实际上只是注意到在哪里检查图像格式是否有效，我正在检查它是否== 2，但它应该是!= 2(如果我错了，请纠正我)，所以它说我的无论哪种方式，图像格式都是无效的。我将尝试在另一个图像上运行我的代码。

如果有人可以提供帮助，那就太好了。

当前输出:

PPM FILE PROGRAM
Memory allocation successful
File format is correct
89~
Image size: 3680602 544108293

所需输出:

PPM FILE PROGRAM
Memory allocation successful
File format is correct
P3
Image size: 125 100

代码:

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

#define MAX_HEIGHT 600
#define MAX_WIDTH 400

struct PPM {
    char format[3]; //PPM format code
    int height, width; //image pixel height and width
    int max; //max rgb colour value
};


struct PPM_Pixel {
    //Create variables to hold the rgb pixel values
    int red;
    int green;
    int blue;
};


struct PPM *getPPM(FILE * file);
void showPPM(struct PPM * image);

int main( void ){

    printf("PPM FILE PROGRAM \n");
    FILE *file;
    // get image file
    // FILE *file;
    file = fopen("aab(1).ppm", "r");
    //if there is no file then return an error
    if(file == NULL){
        fprintf(stderr, "File does not exist\n");
        return 0;
    }

    struct PPM *newPPM = getPPM(file);
    showPPM(file);
    fclose(file);
}


struct PPM *getPPM(FILE * file){

    char buffer[3];
    int c;

    struct PPM *image = NULL;
    if(NULL == (image = malloc(sizeof(struct PPM)))){
        perror("memory allocation for PPM file failed\n");
        exit(1);
    }
    else {
        printf("Memory allocation succesful\n");
    }

    //read the image of the format
    if(!fgets(buffer, sizeof(buffer), file)){
        exit(1);
    }

    //checks the format of the ppm file is correct
    if(buffer[0] != 'P' || buffer[1] != '3'){
        fprintf(stderr, "Invalid image format! \n");
        exit(1);
    }else{
        printf("File format is correct\n");
        printf("%s\n", image->format);
    }

    //checks whether the next character is a comment and skips it
    c = getc(file);
    while(c == '#'){
        while(getc(file) != '\n'){
        c = getc(file);
        }
    }

    //check the image size is valid
    if(fscanf(file, "%d %d", &image->height, &image->width) == 2){
        printf("Invalid imaze size\n");
        exit(1);
    }else{
        printf("Image size: %d %d ", image->height, image->width);
    }

    return image;
}

void showPPM(struct PPM * image){

    struct PPM_Pixel rgb_array[MAX_HEIGHT][MAX_WIDTH];
    int i;
    int j;

    for(i = 0; i<MAX_HEIGHT; i++){
        for(j = 0; j<MAX_WIDTH; j++){
            struct PPM_Pixel newPPM_Pixel;
            if(fscanf(image, "%d %d %d", &newPPM_Pixel.red, &newPPM_Pixel.green, &newPPM_Pixel.blue) == 3){
                rgb_array[i][j] = newPPM_Pixel;
            }
        }
    }
}

抱歉，我不知道如何将输出文本更改为纯文本。

Answer 1

虽然你忘记包含showPPM()的代码，但他的原型(prototype)是

void showPPM(struct PPM * image);

并且您正在传递一个FILE *:

FILE *file;
...
showPPM(file);