Enable the use of separate luminance/chrominance quality scaling with libjpeg v6b code base as well
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@251 632fc199-4ca6-4c93-a231-07263d6284db
diff --git a/rdswitch.c b/rdswitch.c
index d34b400..d406755 100644
--- a/rdswitch.c
+++ b/rdswitch.c
@@ -2,6 +2,7 @@
* rdswitch.c
*
* Copyright (C) 1991-1996, Thomas G. Lane.
+ * Copyright (C) 2010, D. R. Commander.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
@@ -71,7 +72,7 @@
#if JPEG_LIB_VERSION < 70
-static int q_scale_factor = 100;
+static int q_scale_factor[NUM_QUANT_TBLS] = {100, 100, 100, 100};
#endif
GLOBAL(boolean)
@@ -116,7 +117,8 @@
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);
+ jpeg_add_quant_table(cinfo, tblno, table, q_scale_factor[tblno],
+ force_baseline);
#endif
tblno++;
}
@@ -271,6 +273,44 @@
#endif /* C_MULTISCAN_FILES_SUPPORTED */
+#if JPEG_LIB_VERSION < 70
+/* These are the sample quantization tables given in JPEG spec section K.1.
+ * The spec says that the values given produce "good" quality, and
+ * when divided by 2, "very good" quality.
+ */
+static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = {
+ 16, 11, 10, 16, 24, 40, 51, 61,
+ 12, 12, 14, 19, 26, 58, 60, 55,
+ 14, 13, 16, 24, 40, 57, 69, 56,
+ 14, 17, 22, 29, 51, 87, 80, 62,
+ 18, 22, 37, 56, 68, 109, 103, 77,
+ 24, 35, 55, 64, 81, 104, 113, 92,
+ 49, 64, 78, 87, 103, 121, 120, 101,
+ 72, 92, 95, 98, 112, 100, 103, 99
+};
+static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = {
+ 17, 18, 24, 47, 99, 99, 99, 99,
+ 18, 21, 26, 66, 99, 99, 99, 99,
+ 24, 26, 56, 99, 99, 99, 99, 99,
+ 47, 66, 99, 99, 99, 99, 99, 99,
+ 99, 99, 99, 99, 99, 99, 99, 99,
+ 99, 99, 99, 99, 99, 99, 99, 99,
+ 99, 99, 99, 99, 99, 99, 99, 99,
+ 99, 99, 99, 99, 99, 99, 99, 99
+};
+
+
+LOCAL(void)
+jpeg_default_qtables (j_compress_ptr cinfo, boolean force_baseline)
+{
+ jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
+ q_scale_factor[0], force_baseline);
+ jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
+ q_scale_factor[1], force_baseline);
+}
+#endif
+
+
GLOBAL(boolean)
set_quality_ratings (j_compress_ptr cinfo, char *arg, boolean force_baseline)
/* Process a quality-ratings parameter string, of the form
@@ -292,6 +332,8 @@
/* Convert user 0-100 rating to percentage scaling */
#if JPEG_LIB_VERSION >= 70
cinfo->q_scale_factor[tblno] = jpeg_quality_scaling(val);
+#else
+ q_scale_factor[tblno] = jpeg_quality_scaling(val);
#endif
while (*arg && *arg++ != ',') /* advance to next segment of arg string */
;
@@ -299,14 +341,12 @@
/* reached end of parameter, set remaining factors to last value */
#if JPEG_LIB_VERSION >= 70
cinfo->q_scale_factor[tblno] = jpeg_quality_scaling(val);
+#else
+ 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;
}