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/**
* 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 "kern.h"
#include "png.h"
#include <sys/ioctl.h>
#include <linux/fb.h>
/**
* Stop when `try_alt_fbpath` (in scrotty.c) reaches this value.
*/
const int alt_fbpath_limit = 2;
struct data
{
unsigned long start;
unsigned long end;
long hblank;
unsigned long position;
};
/**
* This is called if no framebuffer is found.
*
* It prints a message describing this condition
* and suggests how to resolve it.
*/
void
print_not_found_help (void)
{
fprintf (stderr, _("%s: Unable to find a framebuffer. "
"If you have a file named %s/MAKEDEV, "
"run it with '-d /dev/fb' as root, "
"or try running '%s'.\n"),
execname, DEVDIR, "mknod /dev/fb0 c 29 0 && chgrp video /dev/fb0");
}
/**
* Construct the path to a framebuffer device.
*
* @param altpath The index of the alternative path-pattern to use.
* @param fbno The index of the framebuffer.
* @return The path to the framebuffer device. Errors are impossible.
* This string is statically allocated and must not be deallocated.
*/
char *
get_fbpath (int altpath, int fbno)
{
static char pathbuf[sizeof (DEVDIR "/fb/") + 3 * sizeof (int)];
sprintf (pathbuf, "%s/fb%s%i", DEVDIR, (altpath ? "/" : ""), fbno);
return pathbuf;
}
/**
* Get the dimensions of a framebuffer.
*
* @param fbno The number of the framebuffer.
* @param fbfd File descriptor for framebuffer device.
* @param width Output parameter for the width of the image.
* @param height Output parameter for the height of the image.
* @parma data Additional data to pass to `convert_fb_to_png`.
* @return Zero on success, -1 on error.
*/
int
measure (int fbno, int fbfd, long *restrict width, long *restrict height, void **restrict data)
{
static struct data d;
struct fb_fix_screeninfo fixinfo;
struct fb_var_screeninfo varinfo;
unsigned long int linelength;
if (ioctl (fbfd, FBIOGET_FSCREENINFO, &fixinfo))
goto fail;
if (ioctl (fbfd, FBIOGET_VSCREENINFO, &varinfo))
goto fail;
*width = varinfo.xres;
*height = varinfo.yres;
if (varinfo.bits_per_pixel & 7)
{
fprintf(stderr, _("%s: Unsupported framebuffer configurations: "
"pixels are not encoded in whole bytes.\n"), execname);
exit(1);
}
linelength = fixinfo.line_length / (varinfo.bits_per_pixel / 8);
d.start = varinfo.yoffset * linelength;
d.start += varinfo.xoffset;
d.end = d.start + linelength * varinfo.yres;
d.hblank = linelength - *width;
d.position = 0;
/* TODO depth support */
*data = &d;
return 0;
fail:
return -1;
}
/**
* Convert read data from a framebuffer to PNG pixel data.
*
* @param file The output image file.
* @param buf Buffer with read data.
* @param n The number of read characters.
* @param width3 The width of the image multipled by 3.
* @param adjustment Set to zero if all bytes were converted
* (a whole number of pixels where available,)
* otherwise, set to the number of bytes a
* pixel is encoded.
* @param state Use this to keep track of where in the you
* stopped. It will be 0 on the first call.
* @param data Data from `measure`.
* @return Zero on success, -1 on error.
*/
int
convert_fb_to_png (png_struct *pngbuf, png_byte *restrict pixbuf, const char *restrict buf, size_t n,
long width3, size_t *restrict adjustment, long *restrict state, void *restrict data)
{
const uint32_t *restrict pixel;
int r, g, b;
size_t off;
long x3 = *state;
struct data d = *(struct data *)data;
unsigned long pos = d.position;
long lineend = width3 + d.hblank * 3;
for (off = 0; off < n; off += 4, pos++)
{
/* A pixel in the framebuffer is formatted as `%{blue}%{green}%{red}%{x}`
in big-endian binary, or `%{x}%{red}%{green}%{blue}` in little-endian binary. */
pixel = (const uint32_t *)(buf + off);
r = (*pixel >> 16) & 255;
g = (*pixel >> 8) & 255;
b = (*pixel >> 0) & 255;
if ((pos < d.start) || (pos >= d.end))
continue;
if (x3 < width3)
SAVE_PNG_PIXEL (pixbuf, x3, r, g, b);
x3 += 3;
if (x3 == lineend)
{
SAVE_PNG_ROW (pngbuf, pixbuf);
x3 = 0;
}
}
*adjustment = (off != n ? 4 : 0);
*state = x3;
((struct data *)data)->position = pos;
return 0;
}
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