The Independent JPEG Group's JPEG software v7
diff --git a/jcparam.c b/jcparam.c
index 6fc48f5..c5e85dd 100644
--- a/jcparam.c
+++ b/jcparam.c
@@ -2,6 +2,7 @@
* jcparam.c
*
* Copyright (C) 1991-1998, Thomas G. Lane.
+ * Modified 2003-2008 by Guido Vollbeding.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
@@ -60,6 +61,47 @@
}
+/* 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
+};
+
+
+GLOBAL(void)
+jpeg_default_qtables (j_compress_ptr cinfo, boolean force_baseline)
+/* Set or change the 'quality' (quantization) setting, using default tables
+ * and straight percentage-scaling quality scales.
+ * This entry point allows different scalings for luminance and chrominance.
+ */
+{
+ /* Set up two quantization tables using the specified scaling */
+ jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
+ cinfo->q_scale_factor[0], force_baseline);
+ jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
+ cinfo->q_scale_factor[1], force_baseline);
+}
+
+
GLOBAL(void)
jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor,
boolean force_baseline)
@@ -69,31 +111,6 @@
* applications that insist on a linear percentage scaling.
*/
{
- /* 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
- };
-
/* Set up two quantization tables using the specified scaling */
jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
scale_factor, force_baseline);
@@ -284,6 +301,8 @@
/* Initialize everything not dependent on the color space */
+ cinfo->scale_num = 1; /* 1:1 scaling */
+ cinfo->scale_denom = 1;
cinfo->data_precision = BITS_IN_JSAMPLE;
/* Set up two quantization tables using default quality of 75 */
jpeg_set_quality(cinfo, 75, TRUE);
@@ -320,6 +339,9 @@
/* By default, use the simpler non-cosited sampling alignment */
cinfo->CCIR601_sampling = FALSE;
+ /* By default, apply fancy downsampling */
+ cinfo->do_fancy_downsampling = TRUE;
+
/* No input smoothing */
cinfo->smoothing_factor = 0;