GRASS GIS 7 Programmer's Manual  7.7.svn(2018)-r73570
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pngdriver/write_ppm.c
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1 /*!
2  \file lib/pngdriver/write_ppm.c
3 
4  \brief GRASS png display driver - write PPM image (lower level functions)
5 
6  (C) 2007-2014 by Glynn Clements and the GRASS Development Team
7 
8  This program is free software under the GNU General Public License
9  (>=v2). Read the file COPYING that comes with GRASS for details.
10 
11  \author Glynn Clements
12 */
13 
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <string.h>
17 
18 #include <grass/gis.h>
19 #include "pngdriver.h"
20 
21 void write_ppm(void)
22 {
23  FILE *output;
24  int x, y;
25  unsigned int *p;
26 
27  output = fopen(png.file_name, "wb");
28  if (!output)
29  G_fatal_error("PNG: couldn't open output file %s", png.file_name);
30 
31  fprintf(output, "P6\n%d %d\n255\n", png.width, png.height);
32 
33  for (y = 0, p = png.grid; y < png.height; y++) {
34  for (x = 0; x < png.width; x++, p++) {
35  unsigned int c = *p;
36  int r, g, b, a;
37 
38  png_get_pixel(c, &r, &g, &b, &a);
39 
40  fputc((unsigned char)r, output);
41  fputc((unsigned char)g, output);
42  fputc((unsigned char)b, output);
43  }
44  }
45 
46  fclose(output);
47 }
48 
49 void write_pgm(void)
50 {
51  char *mask_name = G_store(png.file_name);
52  FILE *output;
53  int x, y;
54  unsigned int *p;
55 
56  mask_name[strlen(mask_name) - 2] = 'g';
57 
58  output = fopen(mask_name, "wb");
59  if (!output)
60  G_fatal_error("PNG: couldn't open mask file %s", mask_name);
61 
62  G_free(mask_name);
63 
64  fprintf(output, "P5\n%d %d\n255\n", png.width, png.height);
65 
66  for (y = 0, p = png.grid; y < png.height; y++) {
67  for (x = 0; x < png.width; x++, p++) {
68  unsigned int c = *p;
69  int r, g, b, a;
70 
71  png_get_pixel(c, &r, &g, &b, &a);
72 
73  fputc((unsigned char)(255 - a), output);
74  }
75  }
76 
77  fclose(output);
78 }
void write_pgm(void)
void G_free(void *buf)
Free allocated memory.
Definition: gis/alloc.c:149
int width
Definition: pngdriver.h:43
GRASS png display driver - header file.
char * G_store(const char *s)
Copy string to allocated memory.
Definition: strings.c:86
int height
Definition: pngdriver.h:43
void png_get_pixel(unsigned int pixel, int *r, int *g, int *b, int *a)
Definition: color_table.c:112
#define x
void write_ppm(void)
struct png_state png
void G_fatal_error(const char *msg,...)
Print a fatal error message to stderr.
Definition: gis/error.c:160
double b
Definition: r_raster.c:39
char * file_name
Definition: pngdriver.h:33
unsigned int * grid
Definition: pngdriver.h:44
float g
Definition: named_colr.c:8
fclose(fd)
void output(const char *fmt,...)
double r
Definition: r_raster.c:39