嵌入式linux通用截图工具

程序非原创，是在李先静的工具基础上增加了保存为png格式的支持，在基于framebuffer的x86上和android模拟器上测试成功。下载地址如下:http://blogimg.chinaunix.net/blog/upfile2/090828170135.bz2

源代码如下

/*
 * File:    gsnap.c
 * Author:  Li XianJing
 * Brief:   snap the linux mobile device screen.
 *
 * Copyright (c) 2009  Li XianJing
 *
 * Licensed under the Academic Free License version 2.1
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/*
 * History:
 * ================================================================
 * 2009-08-20 Li XianJing created
 *
 */

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include "jpeglib.h"
#include

struct FB
{
    int fd;
    unsigned size;
    unsigned short *bits;
    struct fb_fix_screeninfo fi;
    struct fb_var_screeninfo vi;
};

#define fb_width(fb) ((fb)->vi.xres)
#define fb_height(fb) ((fb)->vi.yres)
#define fb_size(fb) ((fb)->vi.xres * (fb)->vi.yres * 2)

static int fb_open(struct FB *fb, const char* fbfilename)
{
    fb->fd = open(fbfilename, O_RDWR);
    if (fb->fd < 0)
    {
        fprintf(stderr, "can't open %s\n", fbfilename);
        return -1;
    }

    if (ioctl(fb->fd, FBIOGET_FSCREENINFO, &fb->fi) < 0)
        goto fail;
    if (ioctl(fb->fd, FBIOGET_VSCREENINFO, &fb->vi) < 0)
        goto fail;

    fb->bits = mmap(0, fb_size(fb), PROT_READ | PROT_WRITE,
                    MAP_SHARED, fb->fd, 0);
    if (fb->bits == MAP_FAILED)
        goto fail;

    return 0;
fail:
    printf("%s is not a framebuffer.\n", fbfilename);
    close(fb->fd);

    return -1;
}

static void fb_close(struct FB *fb)
{
    munmap(fb->bits, fb_size(fb));
    close(fb->fd);
}

static int snap2jpg(const char * filename, int quality, struct FB* fb)
{
    int row_stride = 0;
    FILE * outfile = NULL;
    JSAMPROW row_pointer[1] = {0};
    struct jpeg_error_mgr jerr = {0};
    struct jpeg_compress_struct cinfo = {0};

    cinfo.err = jpeg_std_error(&jerr);
    jpeg_create_compress(&cinfo);

    if ((outfile = fopen(filename, "wb+")) == NULL)
    {
        fprintf(stderr, "can't open %s\n", filename);

        return -1;
    }

    jpeg_stdio_dest(&cinfo, outfile);
    cinfo.image_width = fb_width(fb);
    cinfo.image_height = fb_height(fb);
    cinfo.input_components = 3;
    cinfo.in_color_space = JCS_RGB;
    jpeg_set_defaults(&cinfo);
    jpeg_set_quality(&cinfo, quality, TRUE);
    jpeg_start_compress(&cinfo, TRUE);

    row_stride = fb_width(fb) * 2;
    JSAMPLE* image_buffer = malloc(3 * fb_width(fb));

    while (cinfo.next_scanline < cinfo.image_height)
    {
        int i = 0;
        unsigned short* line = fb->bits + cinfo.next_scanline * fb_width(fb);
        for(i = 0; i < fb_width(fb); i++)
        {
            int offset = i * 3;
            unsigned short color = line[i];
            unsigned char r = ((color >> 11) & 0xff) << 3;
            unsigned char g = ((color >> 5) & 0xff)  << 2;
            unsigned char b = (color & 0xff )<< 3;
            image_buffer[offset]     = r;
            image_buffer[offset + 1] = g;
            image_buffer[offset + 2] = b;
        }

        row_pointer[0] = image_buffer;
        (void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
    }

    jpeg_finish_compress(&cinfo);
    fclose(outfile);

    jpeg_destroy_compress(&cinfo);

    return 0;
}

static int snap2png(const char * filename, int quality, struct FB* fb)
{
    FILE *outfile;
    if ((outfile = fopen(filename, "wb+")) == NULL)
    {
        fprintf(stderr, "can't open %s\n", filename);
        return -1;
    }

    /* prepare the standard PNG structures */
    png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,0,0,0);
   
    png_infop info_ptr = png_create_info_struct(png_ptr);

    /* setjmp() must be called in every function that calls a PNG-reading libpng function */
    if (setjmp(png_jmpbuf(png_ptr)))
    {
        png_destroy_write_struct(&png_ptr, &info_ptr);
        fclose(outfile);
        return -1;
    }

    /* initialize the png structure */
    png_init_io(png_ptr, outfile);

    //
    int width = 0;
    int height = 0;
    int bit_depth = 8;
    int color_type = PNG_COLOR_TYPE_RGB;
    int interlace = 0;
    width = fb_width(fb);
    height = fb_height(fb);

    png_set_IHDR (png_ptr, info_ptr, width, height, bit_depth, color_type,
                    (!interlace) ? PNG_INTERLACE_NONE : PNG_INTERLACE_ADAM7,
                    PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);

    /* write the file header information */
    png_write_info(png_ptr, info_ptr);

    printf("[Framebuffer] width = %d height = %d\n",width,height);

    png_bytep row_pointers[height];
    png_byte* image_buffer = malloc(3 * width);

    int i = 0;
    int j = 0;
    unsigned short* line = NULL;
    for( ; i < height; i++ )
    {
        line = fb->bits + i * width;
        for(j = 0; j < width; j++)
        {
            int offset = j * 3;
            image_buffer[offset]     = ((line[j] >> 11) & 0xff) << 3;
            image_buffer[offset + 1] = ((line[j] >> 5) & 0xff)  << 2;
            image_buffer[offset + 2] = (line[j] & 0xff )<< 3;
        }
        row_pointers[i] = image_buffer;
        png_write_rows(png_ptr, &row_pointers[i], 1);
    }
   
    png_destroy_write_struct(&png_ptr, &info_ptr);

    fclose(outfile);

    return 0;

}

int main(int argc, char* argv[])
{
    struct FB fb = {0};
    const char* filename   = NULL;
    const char* fbfilename = NULL;

    if(argc != 3)
    {
        printf("\nusage: %s [jpeg/png] [framebuffer]\n", argv[0]);
        printf("-----------------------------------------\n");
        printf("Powered by broncho()\n");
        return 0;
    }

    filename   = argv[1];
    fbfilename = argv[2];
    if (fb_open(&fb, fbfilename) == 0)
    {
        char *extname = strrchr(argv[1],'.');
        if(!strcasecmp( extname+1, "jpg" ) || !strcasecmp( extname+1, "jpeg" ) )
            snap2jpg(filename, 100, &fb);
        else if (!strcasecmp( extname+1, "png" ))
            snap2png(filename,100,&fb);
        else
                printf("Unsupported file format!\n");
        fb_close(&fb);
    }

    return 0;
}