Add option for setting luminance & chrominance quality independently (currently only works if using libjpeg v7 or v8 code base)
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@248 632fc199-4ca6-4c93-a231-07263d6284db
diff --git a/rdswitch.c b/rdswitch.c
index 4f4bb4f..d34b400 100644
--- a/rdswitch.c
+++ b/rdswitch.c
@@ -9,6 +9,7 @@
* command-line switches. Switches processed here are:
* -qtables file Read quantization tables from text file
* -scans file Read scan script from text file
+ * -quality N[,N,...] Set quality ratings
* -qslots N[,N,...] Set component quantization table selectors
* -sample HxV[,HxV,...] Set component sampling factors
*/
@@ -69,9 +70,12 @@
}
+#if JPEG_LIB_VERSION < 70
+static int q_scale_factor = 100;
+#endif
+
GLOBAL(boolean)
-read_quant_tables (j_compress_ptr cinfo, char * filename,
- int scale_factor, boolean force_baseline)
+read_quant_tables (j_compress_ptr cinfo, char * filename, boolean force_baseline)
/* Read a set of quantization tables from the specified file.
* The file is plain ASCII text: decimal numbers with whitespace between.
* Comments preceded by '#' may be included in the file.
@@ -108,7 +112,12 @@
}
table[i] = (unsigned int) val;
}
- jpeg_add_quant_table(cinfo, tblno, table, scale_factor, force_baseline);
+#if JPEG_LIB_VERSION >= 70
+ jpeg_add_quant_table(cinfo, tblno, table, cinfo->q_scale_factor[tblno],
+ force_baseline);
+#else
+ jpeg_add_quant_table(cinfo, tblno, table, q_scale_factor, force_baseline);
+#endif
tblno++;
}
@@ -263,6 +272,46 @@
GLOBAL(boolean)
+set_quality_ratings (j_compress_ptr cinfo, char *arg, boolean force_baseline)
+/* Process a quality-ratings parameter string, of the form
+ * N[,N,...]
+ * If there are more q-table slots than parameters, the last value is replicated.
+ */
+{
+ int val = 75; /* default value */
+ int tblno;
+ char ch;
+
+ for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) {
+ if (*arg) {
+ ch = ','; /* if not set by sscanf, will be ',' */
+ if (sscanf(arg, "%d%c", &val, &ch) < 1)
+ return FALSE;
+ if (ch != ',') /* syntax check */
+ return FALSE;
+ /* Convert user 0-100 rating to percentage scaling */
+#if JPEG_LIB_VERSION >= 70
+ cinfo->q_scale_factor[tblno] = jpeg_quality_scaling(val);
+#endif
+ while (*arg && *arg++ != ',') /* advance to next segment of arg string */
+ ;
+ } else {
+ /* reached end of parameter, set remaining factors to last value */
+#if JPEG_LIB_VERSION >= 70
+ cinfo->q_scale_factor[tblno] = jpeg_quality_scaling(val);
+#endif
+ }
+ }
+#if JPEG_LIB_VERSION >= 70
+ jpeg_default_qtables(cinfo, force_baseline);
+#else
+ jpeg_set_quality(cinfo, val, force_baseline);
+#endif
+ return TRUE;
+}
+
+
+GLOBAL(boolean)
set_quant_slots (j_compress_ptr cinfo, char *arg)
/* Process a quantization-table-selectors parameter string, of the form
* N[,N,...]