#include #include #include #include #include #include #include int save_jpeg_to_file(image_t *img, char* filename, int quality) { void *dl = dlopen("libjpeg-62.so", 0); if(!dl){ ShowMSG(1, (int)"Can`t load jpeg library!"); return -1; } struct jpeg_error_mgr * (*jpeg_std_error)(struct jpeg_error_mgr *) = dlsym(dl, "jpeg_std_error"); if(!jpeg_std_error) goto err; void (*jpeg_CreateCompress)(j_compress_ptr cinfo, int version, size_t structsize) = dlsym(dl, "jpeg_CreateCompress"); if(!jpeg_CreateCompress) goto err; void (*jpeg_stdio_dest)(j_compress_ptr cinfo, FILE * outfile) = dlsym(dl, "jpeg_stdio_dest"); if(!jpeg_stdio_dest) goto err; void (*jpeg_set_defaults)(j_compress_ptr cinfo) = dlsym(dl, "jpeg_set_defaults"); if(!jpeg_set_defaults) goto err; void (*jpeg_set_quality)(j_compress_ptr cinfo, int quality, boolean force_baseline) = dlsym(dl, "jpeg_set_quality"); if(!jpeg_set_quality) goto err; void (*jpeg_start_compress)(j_compress_ptr cinfo, boolean write_all_tables) = dlsym(dl, "jpeg_start_compress"); if(!jpeg_start_compress) goto err; void (*jpeg_write_scanlines)(j_compress_ptr cinfo, JSAMPARRAY scanlines, JDIMENSION num_lines) = dlsym(dl, "jpeg_write_scanlines"); if(!jpeg_write_scanlines) goto err; void (*jpeg_finish_compress)(j_compress_ptr cinfo) = dlsym(dl, "jpeg_finish_compress"); if(!jpeg_finish_compress) goto err; void (*jpeg_destroy_compress)(j_compress_ptr cinfo) = dlsym(dl, "jpeg_destroy_compress"); if(!jpeg_destroy_compress) goto err; goto success; err: dlclose(dl); return -1; success:; /* This struct contains the JPEG compression parameters and pointers to * working space (which is allocated as needed by the JPEG library). * It is possible to have several such structures, representing multiple * compression/decompression processes, in existence at once. We refer * to any one struct (and its associated working data) as a "JPEG object". */ struct jpeg_compress_struct cinfo; /* This struct represents a JPEG error handler. It is declared separately * because applications often want to supply a specialized error handler * (see the second half of this file for an example). But here we just * take the easy way out and use the standard error handler, which will * print a message on stderr and call exit() if compression fails. * Note that this struct must live as long as the main JPEG parameter * struct, to avoid dangling-pointer problems. */ struct jpeg_error_mgr jerr; /* More stuff */ FILE * outfile; /* target file */ JSAMPLE *scanline; /* pointer to JSAMPLE row[s] */ int row_stride; /* physical row width in image buffer */ /* Step 1: allocate and initialize JPEG compression object */ /* We have to set up the error handler first, in case the initialization * step fails. (Unlikely, but it could happen if you are out of memory.) * This routine fills in the contents of struct jerr, and returns jerr's * address which we place into the link field in cinfo. */ cinfo.err = jpeg_std_error(&jerr); /* Now we can initialize the JPEG compression object. */ jpeg_create_compress(&cinfo); /* Step 2: specify data destination (eg, a file) */ /* Note: steps 2 and 3 can be done in either order. */ /* Here we use the library-supplied code to send compressed data to a * stdio stream. You can also write your own code to do something else. * VERY IMPORTANT: use "b" option to fopen() if you are on a machine that * requires it in order to write binary files. */ if ((outfile = fopen(filename, "wb")) == NULL) { ShowMSG(1, (int)"Error opening file for writing"); dlclose(dl); return 0; } setvbuf(outfile, 0, _IOFBF, 4096); jpeg_stdio_dest(&cinfo, outfile); /* Step 3: set parameters for compression */ /* First we supply a description of the input image. * Four fields of the cinfo struct must be filled in: */ cinfo.image_width = img->w; /* image width and height, in pixels */ cinfo.image_height = img->h; cinfo.input_components = 3; /* # of color components per pixel */ cinfo.in_color_space = JCS_RGB; /* colorspace of input image */ /* Now use the library's routine to set default compression parameters. * (You must set at least cinfo.in_color_space before calling this, * since the defaults depend on the source color space.) */ jpeg_set_defaults(&cinfo); /* Now you can set any non-default parameters you wish to. * Here we just illustrate the use of quality (quantization table) scaling: */ jpeg_set_quality(&cinfo, quality, TRUE /* limit to baseline-JPEG values */); /* Step 4: Start compressor */ /* TRUE ensures that we will write a complete interchange-JPEG file. * Pass TRUE unless you are very sure of what you're doing. */ jpeg_start_compress(&cinfo, TRUE); /* Step 5: while (scan lines remain to be written) */ /* jpeg_write_scanlines(...); */ /* Here we use the library's state variable cinfo.next_scanline as the * loop counter, so that we don't have to keep track ourselves. * To keep things simple, we pass one scanline per call; you can pass * more if you wish, though. */ row_stride = img->w * 3; /* JSAMPLEs per row in image_buffer */ uint32_t *bit = (uint32_t*)img->bitmap; scanline = malloc( row_stride ); for(int posy = 0; posy < img->h; posy++) { for(int posx = 0; posx < img->w; posx++) { uint32_t pixel = pixel32 (img, posx, posy); scanline[posx*3+0] = pixel >> 16 & 0xff; scanline[posx*3+1] = pixel >> 8 & 0xff; scanline[posx*3+2] = pixel & 0xff; } jpeg_write_scanlines(&cinfo, &scanline, 1); } free(scanline); /* Step 6: Finish compression */ jpeg_finish_compress(&cinfo); /* After finish_compress, we can close the output file. */ fclose(outfile); /* Step 7: release JPEG compression object */ /* This is an important step since it will release a good deal of memory. */ jpeg_destroy_compress(&cinfo); dlclose(dl); return 0; }