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brouhaha.tumble/bitblt_g4.c

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/*
* t2p: Create a PDF file from the contents of one or more TIFF
* bilevel image files. The images in the resulting PDF file
* will be compressed using ITU-T T.6 (G4) fax encoding.
*
* PDF routines
* $Id: bitblt_g4.c,v 1.8 2003/03/05 12:44:33 eric Exp $
* Copyright 2003 Eric Smith <eric@brouhaha.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation. Note that permission is
* not granted to redistribute this program under the terms of any
* other version of the General Public License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA
*/
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "bitblt.h"
#include "pdf.h"
#include "pdf_util.h"
#include "pdf_prim.h"
#include "pdf_private.h"
#include "pdf_g4_tables.h"
#define SWAP(type,a,b) do { type temp; temp = a; a = b; b = temp; } while (0)
struct pdf_g4_image
{
double width, height;
double x, y;
double r, g, b; /* fill color, only for ImageMask */
unsigned long Columns;
unsigned long Rows;
bool ImageMask;
bool BlackIs1;
Bitmap *bitmap;
char XObject_name [4];
};
char pdf_new_XObject (pdf_page_handle pdf_page, struct pdf_obj *ind_ref)
{
char XObject_name [4] = "Im ";
XObject_name [2] = ++pdf_page->last_XObject_name;
if (! pdf_page->XObject_dict)
{
pdf_page->XObject_dict = pdf_new_obj (PT_DICTIONARY);
pdf_set_dict_entry (pdf_page->resources, "XObject", pdf_page->XObject_dict);
}
pdf_set_dict_entry (pdf_page->XObject_dict, & XObject_name [0], ind_ref);
return (pdf_page->last_XObject_name);
}
void pdf_write_g4_content_callback (pdf_file_handle pdf_file,
struct pdf_obj *stream,
void *app_data)
{
struct pdf_g4_image *image = app_data;
/* transformation matrix is: width 0 0 height x y cm */
pdf_stream_printf (pdf_file, stream, "q %g 0 0 %g %g %g cm ",
image->width, image->height,
image->x, image->y);
if (image->ImageMask)
pdf_stream_printf (pdf_file, stream, "%g %g %g rg ",
image->r, image->g, image->b);
pdf_stream_printf (pdf_file, stream, "/%s Do Q\r\n",
image->XObject_name);
}
static void pdf_g4_encode_horizontal_run (pdf_file_handle pdf_file,
struct pdf_obj *stream,
bool black,
uint32_t run_length)
{
uint32_t i;
while (run_length >= 2560)
{
pdf_stream_write_bits (pdf_file, stream, 12, 0x01f);
run_length -= 2560;
}
if (run_length >= 1792)
{
i = (run_length - 1792) >> 6;
pdf_stream_write_bits (pdf_file, stream,
g4_long_makeup_code [i].count,
g4_long_makeup_code [i].bits);
run_length -= (1792 + (i << 6));
}
else if (run_length >= 64)
{
i = (run_length >> 6) - 1;
pdf_stream_write_bits (pdf_file, stream,
g4_makeup_code [black] [i].count,
g4_makeup_code [black] [i].bits);
run_length -= (i + 1) << 6;
}
pdf_stream_write_bits (pdf_file, stream,
g4_h_code [black] [run_length].count,
g4_h_code [black] [run_length].bits);
}
uint32_t find_transition (uint8_t *data,
uint32_t pos,
uint32_t width)
{
if (! data)
return (width);
return (0); /* $$$ */
}
static void pdf_g4_encode_row (pdf_file_handle pdf_file,
struct pdf_obj *stream,
uint32_t width,
uint8_t *ref,
uint8_t *row)
{
int a0, a1, a2;
int b1, b2;
a0 = -1;
while (a0 < width)
{
/* find a1, a2 */
a1 = find_transition (row, a0, width);
a2 = find_transition (row, a1, width);
/* find b1, b2 */
b1 = find_transition (ref, a0, width);
if (0) /* $$$ b1 color = a0 color */
b1 = find_transition (ref, b1, width);
b2 = find_transition (ref, b2, width);
if (b2 < a1)
{
/* pass mode - 0001 */
pdf_stream_write_bits (pdf_file, stream, 4, 0x1);
a0 = b2;
}
else if (abs (a1 - b1) <= 3)
{
/* vertical mode */
pdf_stream_write_bits (pdf_file, stream,
g4_vert_code [3 + a1 - b1].count,
g4_vert_code [3 + a1 - b1].bits);
a0 = a1;
}
else
{
/* horizontal mode - 001 */
pdf_stream_write_bits (pdf_file, stream, 3, 0x1);
pdf_g4_encode_horizontal_run (pdf_file, stream,
0 /* $$$ color (a0) */, a1 - a0);
pdf_g4_encode_horizontal_run (pdf_file, stream,
1 /* $$$ color (a1) */, a2 - a1);
a0 = a2;
}
}
}
void pdf_write_g4_fax_image_callback (pdf_file_handle pdf_file,
struct pdf_obj *stream,
void *app_data)
{
struct pdf_g4_image *image = app_data;
uint32_t row;
word_type *ref_line = NULL; /* reference (previous) row */
word_type *line = image->bitmap->bits;
for (row = image->bitmap->rect.min.y;
row < image->bitmap->rect.max.y;
row++)
{
pdf_g4_encode_row (pdf_file, stream, image->Columns,
(uint8_t *) ref_line,
(uint8_t *) line);
ref_line = line;
line += image->bitmap->row_words;
}
/* write EOFB code */
pdf_stream_write_bits (pdf_file, stream, 24, 0x001001);
pdf_stream_flush_bits (pdf_file, stream);
}
void pdf_write_g4_fax_image (pdf_page_handle pdf_page,
double x,
double y,
double width,
double height,
Bitmap *bitmap,
bool ImageMask,
double r, /* RGB fill color, only for ImageMask */
double g,
double b,
bool BlackIs1) /* boolean, typ. false */
{
struct pdf_g4_image *image;
struct pdf_obj *stream;
struct pdf_obj *stream_dict;
struct pdf_obj *decode_parms;
struct pdf_obj *content_stream;
image = pdf_calloc (1, sizeof (struct pdf_g4_image));
image->width = width;
image->height = height;
image->x = x;
image->y = y;
image->r = r;
image->g = g;
image->b = b;
image->bitmap = bitmap;
image->Columns = bitmap->rect.max.x - bitmap->rect.min.x;
image->Rows = bitmap->rect.max.y - bitmap->rect.min.y;
image->ImageMask = ImageMask;
image->BlackIs1 = BlackIs1;
stream_dict = pdf_new_obj (PT_DICTIONARY);
stream = pdf_new_ind_ref (pdf_page->pdf_file,
pdf_new_stream (pdf_page->pdf_file,
stream_dict,
& pdf_write_g4_fax_image_callback,
image));
strcpy (& image->XObject_name [0], "Im ");
image->XObject_name [2] = pdf_new_XObject (pdf_page, stream);
pdf_set_dict_entry (stream_dict, "Type", pdf_new_name ("XObject"));
pdf_set_dict_entry (stream_dict, "Subtype", pdf_new_name ("Image"));
pdf_set_dict_entry (stream_dict, "Name", pdf_new_name (& image->XObject_name [0]));
pdf_set_dict_entry (stream_dict, "Width", pdf_new_integer (image->Columns));
pdf_set_dict_entry (stream_dict, "Height", pdf_new_integer (image->Rows));
pdf_set_dict_entry (stream_dict, "BitsPerComponent", pdf_new_integer (1));
if (ImageMask)
pdf_set_dict_entry (stream_dict, "ImageMask", pdf_new_bool (ImageMask));
else
pdf_set_dict_entry (stream_dict, "ColorSpace", pdf_new_name ("DeviceGray"));
decode_parms = pdf_new_obj (PT_DICTIONARY);
pdf_set_dict_entry (decode_parms,
"K",
pdf_new_integer (-1));
pdf_set_dict_entry (decode_parms,
"Columns",
pdf_new_integer (image->Columns));
pdf_set_dict_entry (decode_parms,
"Rows",
pdf_new_integer (image->Rows));
if (BlackIs1)
pdf_set_dict_entry (decode_parms,
"BlackIs1",
pdf_new_bool (BlackIs1));
pdf_stream_add_filter (stream, "CCITTFaxDecode", decode_parms);
/* the following will write the stream, using our callback function to
get the actual data */
pdf_write_ind_obj (pdf_page->pdf_file, stream);
content_stream = pdf_new_ind_ref (pdf_page->pdf_file,
pdf_new_stream (pdf_page->pdf_file,
pdf_new_obj (PT_DICTIONARY),
& pdf_write_g4_content_callback,
image));
pdf_set_dict_entry (pdf_page->page_dict, "Contents", content_stream);
pdf_write_ind_obj (pdf_page->pdf_file, content_stream);
}
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