diff options
Diffstat (limited to 'cjpeg.c')
| -rw-r--r-- | cjpeg.c | 38 |
1 files changed, 21 insertions, 17 deletions
@@ -149,7 +149,7 @@ usage (void) #endif fprintf(stderr, "Switches (names may be abbreviated):\n"); - fprintf(stderr, " -quality N Compression quality (0..100; 5-95 is useful range)\n"); + fprintf(stderr, " -quality N[,...] Compression quality (0..100; 5-95 is useful range)\n"); fprintf(stderr, " -grayscale Create monochrome JPEG file\n"); #ifdef ENTROPY_OPT_SUPPORTED fprintf(stderr, " -optimize Optimize Huffman table (smaller file, but slow compression)\n"); @@ -157,6 +157,9 @@ usage (void) #ifdef C_PROGRESSIVE_SUPPORTED fprintf(stderr, " -progressive Create progressive JPEG file\n"); #endif +#ifdef DCT_SCALING_SUPPORTED + fprintf(stderr, " -scale M/N Scale image by fraction M/N, eg, 1/2\n"); +#endif #ifdef TARGA_SUPPORTED fprintf(stderr, " -targa Input file is Targa format (usually not needed)\n"); #endif @@ -209,21 +212,16 @@ parse_switches (j_compress_ptr cinfo, int argc, char **argv, { int argn; char * arg; - int quality; /* -quality parameter */ - int q_scale_factor; /* scaling percentage for -qtables */ boolean force_baseline; boolean simple_progressive; + char * qualityarg = NULL; /* saves -quality parm if any */ char * qtablefile = NULL; /* saves -qtables filename if any */ char * qslotsarg = NULL; /* saves -qslots parm if any */ char * samplearg = NULL; /* saves -sample parm if any */ char * scansarg = NULL; /* saves -scans parm if any */ /* Set up default JPEG parameters. */ - /* Note that default -quality level need not, and does not, - * match the default scaling for an explicit -qtables argument. - */ - quality = 75; /* default -quality value */ - q_scale_factor = 100; /* default to no scaling for -qtables */ + force_baseline = FALSE; /* by default, allow 16-bit quantizers */ simple_progressive = FALSE; is_targa = FALSE; @@ -328,13 +326,10 @@ parse_switches (j_compress_ptr cinfo, int argc, char **argv, #endif } else if (keymatch(arg, "quality", 1)) { - /* Quality factor (quantization table scaling factor). */ + /* Quality ratings (quantization table scaling factors). */ if (++argn >= argc) /* advance to next argument */ usage(); - if (sscanf(argv[argn], "%d", &quality) != 1) - usage(); - /* Change scale factor in case -qtables is present. */ - q_scale_factor = jpeg_quality_scaling(quality); + qualityarg = argv[argn]; } else if (keymatch(arg, "qslots", 2)) { /* Quantization table slot numbers. */ @@ -382,7 +377,15 @@ parse_switches (j_compress_ptr cinfo, int argc, char **argv, * default sampling factors. */ - } else if (keymatch(arg, "scans", 2)) { + } else if (keymatch(arg, "scale", 4)) { + /* Scale the image by a fraction M/N. */ + if (++argn >= argc) /* advance to next argument */ + usage(); + if (sscanf(argv[argn], "%d/%d", + &cinfo->scale_num, &cinfo->scale_denom) != 2) + usage(); + + } else if (keymatch(arg, "scans", 4)) { /* Set scan script. */ #ifdef C_MULTISCAN_FILES_SUPPORTED if (++argn >= argc) /* advance to next argument */ @@ -422,11 +425,12 @@ parse_switches (j_compress_ptr cinfo, int argc, char **argv, /* Set quantization tables for selected quality. */ /* Some or all may be overridden if -qtables is present. */ - jpeg_set_quality(cinfo, quality, force_baseline); + if (qualityarg != NULL) /* process -quality if it was present */ + if (! set_quality_ratings(cinfo, qualityarg, force_baseline)) + usage(); if (qtablefile != NULL) /* process -qtables if it was present */ - if (! read_quant_tables(cinfo, qtablefile, - q_scale_factor, force_baseline)) + if (! read_quant_tables(cinfo, qtablefile, force_baseline)) usage(); if (qslotsarg != NULL) /* process -qslots if it was present */ |