/**
* fb2png Save screenshot into .png.
*
* Copyright (C) 2012 Kyan <kyan.ql.he@gmail.com>
*
* 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 2 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <errno.h>
#include <fcntl.h>
#include <linux/fb.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
#include "log.h"
#include "fb2png.h"
#include "fb.h"
/**
* Get the {@code struct fb} from device's framebuffer.
* Return
* 0 for success.
*/
int get_device_fb(const char* path, struct fb *fb)
{
int fd;
int bytespp;
int offset;
char *x;
struct fb_var_screeninfo vinfo;
fd = open(path, O_RDONLY);
if (fd < 0) return -1;
if(ioctl(fd, FBIOGET_VSCREENINFO, &vinfo) < 0) {
D("ioctl failed, %s\n", strerror(errno));
return -1;
}
bytespp = vinfo.bits_per_pixel / 8;
fb->bpp = vinfo.bits_per_pixel;
fb->size = vinfo.xres * vinfo.yres * bytespp;
fb->width = vinfo.xres;
fb->height = vinfo.yres;
fb->red_offset = vinfo.red.offset;
fb->red_length = vinfo.red.length;
fb->green_offset = vinfo.green.offset;
fb->green_length = vinfo.green.length;
fb->blue_offset = vinfo.blue.offset;
fb->blue_length = vinfo.blue.length;
fb->alpha_offset = vinfo.transp.offset;
fb->alpha_length = vinfo.transp.length;
#ifdef ANDROID
/* HACK: for several of 3d cores a specific alignment
* is required so the start of the fb may not be an integer number of lines
* from the base. As a result we are storing the additional offset in
* xoffset. This is not the correct usage for xoffset, it should be added
* to each line, not just once at the beginning */
offset = vinfo.xoffset * bytespp;
/* Android use double-buffer, capture 2nd */
offset += vinfo.xres * vinfo.yoffset * bytespp;
#else
offset = 0;
#endif
x = malloc(fb->size);
if (!x) return -1;
lseek(fd, offset, SEEK_SET);
if (read(fd, x ,fb->size) != fb->size) goto oops;
fb->data = x;
close(fd);
return 0;
oops:
close(fd);
free(x);
return -1;
}
int fb2png(const char *path)
{
struct fb fb;
int ret;
#ifdef ANDROID
ret = get_device_fb("/dev/graphics/fb0", &fb);
#else
ret = get_device_fb("/dev/fb0", &fb);
#endif
if (ret) {
D("Failed to read framebuffer.");
return -1;
}
fb_dump(&fb);
return fb_save_png(&fb, path);
}
