The Independent JPEG Group's JPEG software v6
diff --git a/jcparam.c b/jcparam.c
index 234aa56..29862d3 100644
--- a/jcparam.c
+++ b/jcparam.c
@@ -1,7 +1,7 @@
/*
* jcparam.c
*
- * Copyright (C) 1991-1994, Thomas G. Lane.
+ * Copyright (C) 1991-1995, Thomas G. Lane.
* This file is part of the Independent JPEG Group's software.
* For conditions of distribution and use, see the accompanying README file.
*
@@ -279,15 +279,16 @@
cinfo->arith_ac_K[i] = 5;
}
+ /* Default is no multiple-scan output */
+ cinfo->scan_info = NULL;
+ cinfo->num_scans = 0;
+
/* Expect normal source image, not raw downsampled data */
cinfo->raw_data_in = FALSE;
/* Use Huffman coding, not arithmetic coding, by default */
cinfo->arith_code = FALSE;
- /* Color images are interleaved by default */
- cinfo->interleave = TRUE;
-
/* By default, don't do extra passes to optimize entropy coding */
cinfo->optimize_coding = FALSE;
/* The standard Huffman tables are only valid for 8-bit data precision.
@@ -368,7 +369,6 @@
#define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl) \
(compptr = &cinfo->comp_info[index], \
- compptr->component_index = (index), \
compptr->component_id = (id), \
compptr->h_samp_factor = (hsamp), \
compptr->v_samp_factor = (vsamp), \
@@ -399,9 +399,9 @@
case JCS_RGB:
cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */
cinfo->num_components = 3;
- SET_COMP(0, 'R', 1,1, 0, 0,0);
- SET_COMP(1, 'G', 1,1, 0, 0,0);
- SET_COMP(2, 'B', 1,1, 0, 0,0);
+ SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0);
+ SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0);
+ SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0);
break;
case JCS_YCbCr:
cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
@@ -415,10 +415,10 @@
case JCS_CMYK:
cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */
cinfo->num_components = 4;
- SET_COMP(0, 'C', 1,1, 0, 0,0);
- SET_COMP(1, 'M', 1,1, 0, 0,0);
- SET_COMP(2, 'Y', 1,1, 0, 0,0);
- SET_COMP(3, 'K', 1,1, 0, 0,0);
+ SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0);
+ SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0);
+ SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0);
+ SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0);
break;
case JCS_YCCK:
cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */
@@ -441,3 +441,135 @@
ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
}
}
+
+
+#ifdef C_PROGRESSIVE_SUPPORTED
+
+LOCAL jpeg_scan_info *
+fill_a_scan (jpeg_scan_info * scanptr, int ci,
+ int Ss, int Se, int Ah, int Al)
+/* Support routine: generate one scan for specified component */
+{
+ scanptr->comps_in_scan = 1;
+ scanptr->component_index[0] = ci;
+ scanptr->Ss = Ss;
+ scanptr->Se = Se;
+ scanptr->Ah = Ah;
+ scanptr->Al = Al;
+ scanptr++;
+ return scanptr;
+}
+
+LOCAL jpeg_scan_info *
+fill_scans (jpeg_scan_info * scanptr, int ncomps,
+ int Ss, int Se, int Ah, int Al)
+/* Support routine: generate one scan for each component */
+{
+ int ci;
+
+ for (ci = 0; ci < ncomps; ci++) {
+ scanptr->comps_in_scan = 1;
+ scanptr->component_index[0] = ci;
+ scanptr->Ss = Ss;
+ scanptr->Se = Se;
+ scanptr->Ah = Ah;
+ scanptr->Al = Al;
+ scanptr++;
+ }
+ return scanptr;
+}
+
+LOCAL jpeg_scan_info *
+fill_dc_scans (jpeg_scan_info * scanptr, int ncomps, int Ah, int Al)
+/* Support routine: generate interleaved DC scan if possible, else N scans */
+{
+ int ci;
+
+ if (ncomps <= MAX_COMPS_IN_SCAN) {
+ /* Single interleaved DC scan */
+ scanptr->comps_in_scan = ncomps;
+ for (ci = 0; ci < ncomps; ci++)
+ scanptr->component_index[ci] = ci;
+ scanptr->Ss = scanptr->Se = 0;
+ scanptr->Ah = Ah;
+ scanptr->Al = Al;
+ scanptr++;
+ } else {
+ /* Noninterleaved DC scan for each component */
+ scanptr = fill_scans(scanptr, ncomps, 0, 0, Ah, Al);
+ }
+ return scanptr;
+}
+
+
+/*
+ * Create a recommended progressive-JPEG script.
+ * cinfo->num_components and cinfo->jpeg_color_space must be correct.
+ */
+
+GLOBAL void
+jpeg_simple_progression (j_compress_ptr cinfo)
+{
+ int ncomps = cinfo->num_components;
+ int nscans;
+ jpeg_scan_info * scanptr;
+
+ /* Safety check to ensure start_compress not called yet. */
+ if (cinfo->global_state != CSTATE_START)
+ ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
+
+ /* Figure space needed for script. Calculation must match code below! */
+ if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
+ /* Custom script for YCbCr color images. */
+ nscans = 10;
+ } else {
+ /* All-purpose script for other color spaces. */
+ if (ncomps > MAX_COMPS_IN_SCAN)
+ nscans = 6 * ncomps; /* 2 DC + 4 AC scans per component */
+ else
+ nscans = 2 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */
+ }
+
+ /* Allocate space for script. */
+ /* We use permanent pool just in case application re-uses script. */
+ scanptr = (jpeg_scan_info *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
+ nscans * SIZEOF(jpeg_scan_info));
+ cinfo->scan_info = scanptr;
+ cinfo->num_scans = nscans;
+
+ if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
+ /* Custom script for YCbCr color images. */
+ /* Initial DC scan */
+ scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
+ /* Initial AC scan: get some luma data out in a hurry */
+ scanptr = fill_a_scan(scanptr, 0, 1, 5, 0, 2);
+ /* Chroma data is too small to be worth expending many scans on */
+ scanptr = fill_a_scan(scanptr, 2, 1, 63, 0, 1);
+ scanptr = fill_a_scan(scanptr, 1, 1, 63, 0, 1);
+ /* Complete spectral selection for luma AC */
+ scanptr = fill_a_scan(scanptr, 0, 6, 63, 0, 2);
+ /* Refine next bit of luma AC */
+ scanptr = fill_a_scan(scanptr, 0, 1, 63, 2, 1);
+ /* Finish DC successive approximation */
+ scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
+ /* Finish AC successive approximation */
+ scanptr = fill_a_scan(scanptr, 2, 1, 63, 1, 0);
+ scanptr = fill_a_scan(scanptr, 1, 1, 63, 1, 0);
+ /* Luma bottom bit comes last since it's usually largest scan */
+ scanptr = fill_a_scan(scanptr, 0, 1, 63, 1, 0);
+ } else {
+ /* All-purpose script for other color spaces. */
+ /* Successive approximation first pass */
+ scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
+ scanptr = fill_scans(scanptr, ncomps, 1, 5, 0, 2);
+ scanptr = fill_scans(scanptr, ncomps, 6, 63, 0, 2);
+ /* Successive approximation second pass */
+ scanptr = fill_scans(scanptr, ncomps, 1, 63, 2, 1);
+ /* Successive approximation final pass */
+ scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
+ scanptr = fill_scans(scanptr, ncomps, 1, 63, 1, 0);
+ }
+}
+
+#endif /* C_PROGRESSIVE_SUPPORTED */