C++ linux下使用X11实现屏幕截图（续）_x11截屏

使用libpng库将XGetImage获取到的内容保存为PNG格式的文件。以下是一个示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <png.h>
 
void saveImageToPNG(XImage *image, const char *filename) {
    FILE *fp = fopen(filename, "wb");
    if (!fp) {
        fprintf(stderr, "Error: Failed to open file '%s' for writing.\n", filename);
        return;
    }
 
    png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
    if (!png_ptr) {
        fprintf(stderr, "Error: Failed to create PNG write structure.\n");
        fclose(fp);
        return;
    }
 
    png_infop info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr) {
        fprintf(stderr, "Error: Failed to create PNG info structure.\n");
        png_destroy_write_struct(&png_ptr, NULL);
        fclose(fp);
        return;
    }
 
    if (setjmp(png_jmpbuf(png_ptr))) {
        fprintf(stderr, "Error: Failed to set PNG jump buffer.\n");
        png_destroy_write_struct(&png_ptr, &info_ptr);
        fclose(fp);
        return;
    }
 
    png_init_io(png_ptr, fp);
 
    png_set_IHDR(png_ptr, info_ptr, image->width, image->height, 8, PNG_COLOR_TYPE_RGBA,
                 PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
 
    png_write_info(png_ptr, info_ptr);
 
    png_bytep *row_pointers = (png_bytep *)malloc(image->height * sizeof(png_bytep));
    for (int y = 0; y < image->height; y++) {
        row_pointers[y] = (png_bytep)(image->data + y * image->bytes_per_line);
    }
 
    png_write_image(png_ptr, row_pointers);
    png_write_end(png_ptr, NULL);
 
    free(row_pointers);
    png_destroy_write_struct(&png_ptr, &info_ptr);
    fclose(fp);
}
 
int main() {
    Display *display = XOpenDisplay(NULL);
    if (!display) {
        fprintf(stderr, "Error: Failed to open display.\n");
        return 1;
    }
 
    Window root = DefaultRootWindow(display);
    XImage *image = XGetImage(display, root, 0, 0, 1920, 1080, AllPlanes, ZPixmap);
    if (!image) {
        fprintf(stderr, "Error: Failed to get image from display.\n");
        XCloseDisplay(display);
        return 1;
    }
 
    saveImageToPNG(image, "screenshot.png");
 
    XDestroyImage(image);
    XCloseDisplay(display);
 
    return 0;
}