diff options
Diffstat (limited to 'fitz/image_jpeg.c')
| -rw-r--r-- | fitz/image_jpeg.c | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/fitz/image_jpeg.c b/fitz/image_jpeg.c index e66f3d8d..432ba86d 100644 --- a/fitz/image_jpeg.c +++ b/fitz/image_jpeg.c @@ -145,3 +145,70 @@ fz_load_jpeg(fz_context *ctx, unsigned char *rbuf, int rlen) return image; } + +void +fz_load_jpeg_info(fz_context *ctx, unsigned char *rbuf, int rlen, int *xp, int *yp, int *xresp, int *yresp, fz_colorspace **cspacep) +{ + struct jpeg_decompress_struct cinfo; + struct jpeg_error_mgr err; + struct jpeg_source_mgr src; + + fz_try(ctx) + { + cinfo.client_data = ctx; + cinfo.err = jpeg_std_error(&err); + err.error_exit = error_exit; + + jpeg_create_decompress(&cinfo); + + cinfo.src = &src; + src.init_source = init_source; + src.fill_input_buffer = fill_input_buffer; + src.skip_input_data = skip_input_data; + src.resync_to_restart = jpeg_resync_to_restart; + src.term_source = term_source; + src.next_input_byte = rbuf; + src.bytes_in_buffer = rlen; + + jpeg_read_header(&cinfo, 1); + + if (cinfo.num_components == 1) + *cspacep = fz_device_gray; + else if (cinfo.num_components == 3) + *cspacep = fz_device_rgb; + else if (cinfo.num_components == 4) + *cspacep = fz_device_cmyk; + else + fz_throw(ctx, "bad number of components in jpeg: %d", cinfo.num_components); + + *xp = cinfo.image_width; + *yp = cinfo.image_height; + + if (cinfo.density_unit == 1) + { + *xresp = cinfo.X_density; + *yresp = cinfo.Y_density; + } + else if (cinfo.density_unit == 2) + { + *xresp = cinfo.X_density * 254 / 100; + *yresp = cinfo.Y_density * 254 / 100; + } + else + { + *xresp = 0; + *yresp = 0; + } + + if (*xresp <= 0) *xresp = 72; + if (*yresp <= 0) *yresp = 72; + } + fz_always(ctx) + { + jpeg_destroy_decompress(&cinfo); + } + fz_catch(ctx) + { + fz_rethrow(ctx); + } +} |