如何在Linux上读取C++中的JPEG和PNG像素？

#include<iostream>
#include <jpeglib.h>
#include <png.h>

void readJPEG(const char* filename) {
    FILE* infile;
    JSAMPARRAY buffer;
    int row_stride;
    struct jpeg_decompress_struct cinfo;
    struct jpeg_error_mgr jerr;

    infile = fopen(filename, "rb");
    if (infile == NULL) {
        std::cerr << "Error opening JPEG file"<< std::endl;
        return;
    }

    cinfo.err = jpeg_std_error(&jerr);
    jpeg_create_decompress(&cinfo);
    jpeg_stdio_src(&cinfo, infile);
    jpeg_read_header(&cinfo, TRUE);

    jpeg_start_decompress(&cinfo);
    row_stride = cinfo.output_width * cinfo.output_components;

    buffer = (*cinfo.mem->alloc_sarray)
        ((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);

    while (cinfo.output_scanline < cinfo.output_height) {
        jpeg_read_scanlines(&cinfo, buffer, 1);
    }

    jpeg_finish_decompress(&cinfo);
    jpeg_destroy_decompress(&cinfo);
    fclose(infile);
}

void readPNG(const char* filename) {
    FILE* infile;
    png_structp png_ptr;
    png_infop info_ptr;
    int width, height, bit_depth, color_type;

    infile = fopen(filename, "rb");
    if (infile == NULL) {
        std::cerr << "Error opening PNG file"<< std::endl;
        return;
    }

    png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
    info_ptr = png_create_info_struct(png_ptr);
    if (setjmp(png_jmpbuf(png_ptr))) {
        std::cerr << "Error during init_io"<< std::endl;
        return;
    }

    png_init_io(png_ptr, infile);
    png_read_info(png_ptr, info_ptr);
    width = png_get_image_width(png_ptr, info_ptr);
    height = png_get_image_height(png_ptr, info_ptr);
    bit_depth = png_get_bit_depth(png_ptr, info_ptr);
    color_type = png_get_color_type(png_ptr, info_ptr);

    // TODO: Process the image data

    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
    fclose(infile);
}

int main() {
    readJPEG("image.jpg");
    readPNG("image.png");
    return 0;
}