/**
* scrotty — Screenshot program for Linux's TTY
*
* Copyright © 2014, 2015 Mattias Andrée (maandree@member.fsf.org)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include "common.h"
#include "png.h"
#ifdef __GNUC__
# pragma GCC diagnostic ignored "-Wpadded"
#endif
#include <png.h>
/*
* Rationale:
*
* Users want their files in PNG (most often), not PNM.
* Calling an external program for conversion poses
* potential security risks, and is slower.
*/
/**
* Convert an image from PNM to PNG.
*
* This is a very limited conversion implementation.
* It is not generally reusable. It makes assumptions
* that are true only necessarily for this program.
*
* @param fdin The file descriptor for the image to convert (PNM).
* @param fdout The file descriptor for the output image (PNG).
* @return Zero on success, -1 on error.
*/
int
convert (int fdin, int fdout)
{
#define SCAN(...) do { if (fscanf(in, __VA_ARGS__) != 1) goto fail; } while (0)
FILE *in = NULL;
FILE *out = NULL;
long height, width, width3;
long y, x, r, g, b;
png_byte *pixbuf = 0;
png_struct *pngbuf = NULL;
png_info *pnginfo = NULL;
int saved_errno = 0, rc, c;
/* Get a FILE * for the input, we want to use fscanf, there is no dscanf. */
in = fdopen (fdin, "r");
if (in == NULL)
goto fail;
/* Get a FILE * for the output, libpng wants a FILE *, not a file descriptor. */
out = fdopen (fdout, "w");
if (out == NULL)
goto fail;
/* Read head. */
do c = fgetc(in); while ((c != '\n') && (c != EOF));
SCAN ("%li ", &width);
SCAN ("%li\n", &height);
do c = fgetc(in); while ((c != '\n') && (c != EOF));
/* Allocte structures for the PNG. */
width3 = width * 3;
pixbuf = malloc ((size_t)width3 * sizeof (png_byte));
if (pixbuf == NULL)
goto fail;
pngbuf = png_create_write_struct (png_get_libpng_ver (NULL), NULL, NULL, NULL);
if (pngbuf == NULL)
goto fail;
pnginfo = png_create_info_struct (pngbuf);
if (pnginfo == NULL)
goto fail;
/* Initialise PNG write, and write head. */
if (setjmp (png_jmpbuf(pngbuf))) /* Failing libpng calls jump here. */
goto fail;
png_init_io (pngbuf, out);
png_set_IHDR (pngbuf, pnginfo, (png_uint_32)width, (png_uint_32)height,
8 /* bit depth */, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_write_info (pngbuf, pnginfo);
/* Read and convert body. */
for (y = 0; y < height; y++)
{
for (x = 0; x < width3; x += 3)
{
SCAN ("%li\n", &r);
SCAN ("%li\n", &g);
SCAN ("%li\n", &b);
pixbuf[x + 0] = (png_byte)r;
pixbuf[x + 1] = (png_byte)g;
pixbuf[x + 2] = (png_byte)b;
}
png_write_row (pngbuf, pixbuf);
}
png_write_end (pngbuf, pnginfo);
rc = 0;
goto cleanup;
fail:
saved_errno = errno;
rc = -1;
goto cleanup;
cleanup:
png_destroy_write_struct (&pngbuf, (pnginfo ? &pnginfo : NULL));
if (in != NULL)
fclose (in);
if (out != NULL)
fclose (out);
free (pixbuf);
return errno = saved_errno, rc;
}
