gdImageTrueColorToPalette  843 http/modules/ngx_http_image_filter_module.c             gdImageTrueColorToPalette(dst, 1, 256);
gdImageTrueColorToPalette  926 http/modules/ngx_http_image_filter_module.c                 gdImageTrueColorToPalette(dst, 1, 256);