c++ - 从QByteArray使用libjpeg加载jpeg图像纹理

嗨，我有一个从QNetworkReply获得的jpeg图像的QByteArray。我到处都看到从文件读取并解压缩的jpeg图像，

FILE * infile;
......
if ((infile = fopen(filename, "rb")) == NULL)
{
     fprintf(stderr, "can't open %s\n", filename);
     exit(1);
}
jpeg_stdio_src(&cinfo, infile);
jpeg_read_header(&cinfo, 0);
jpeg_start_decompress(&cinfo);

然后

while (scan lines remain to be read)
      jpeg_read_scanlines(...);

但是，如何从QByteArray而不是文件/ stdio流读取它？

最佳答案

用

void jpeg_mem_src(j_decompress_ptr cinfo, unsigned char * inbuffer,
              unsigned long insize);

代替jpeg_stdio_src

 QByteArray qarr;

 jpeg_decompress_struct cinfo;
 jpeg_mem_src(&cinfo, qarr.data(), qarr.size());
 jpeg_read_header(&cinfo, TRUE);
 jpeg_start_decompress(&cinfo);

 /// etc..