android 使用jpeg库截屏

jtest.c

#include <string.h>  #include <stdlib.h>//#include <jni.h>  #include <math.h>  #include <stdio.h>  #include <unistd.h>#include <stdio.h>#include <fcntl.h>#include <linux/fb.h>#include <sys/mman.h>#include <stdlib.h>#include <errno.h>#include <string.h>typedef uint8_t BYTE;  #define true 1  #define false 0  #include "jpeglib.h"#define FB_DEVICE "/dev/graphics/fb0"static int g_fd;typedef struct{int x;int y;}point;typedef struct{int w;    /* width */int h;    /* high */int bpp;  /* bits per pixel */unsigned char *fbmem;}screen;int init_fb(screen *fb){if ((g_fd = open(FB_DEVICE, O_RDWR)) < 0){ fprintf(stderr, "Open %s failed:%s\n", FB_DEVICE, strerror(errno));return -1; }   struct fb_var_screeninfo fb_var;struct fb_fix_screeninfo fb_fix;if (ioctl(g_fd, FBIOGET_VSCREENINFO, &fb_var) < 0){ fprintf(stderr, "fb ioctl failed:%s\n", strerror(errno));return -1; }   if (ioctl(g_fd, FBIOGET_FSCREENINFO, &fb_fix) < 0){ fprintf(stderr, "fb ioctl failed:%s\n", strerror(errno));return -1; }   fb->w = fb_fix.line_length / 4;fb->h = fb_var.yres;fb->bpp = fb_var.bits_per_pixel;printf("--->^_^ %d, %d, %d, %d\n", fb_var.xres_virtual, fb_var.yres_virtual, fb_var.xoffset, fb_var.yoffset);printf("--->^_^ %d\n", fb_fix.line_length);#if 1printf("width:%d\thign:%d\tbpp:%d\n",fb->w, fb->h, fb->bpp);#endiffb->fbmem = mmap(0, fb->w * fb->h * fb->bpp /8,PROT_READ | PROT_WRITE, MAP_SHARED, g_fd, 0);if (fb->fbmem == MAP_FAILED){fprintf(stderr, "fb mmap failed:%s\n", strerror(errno));return -1;}close(g_fd);return 0;}int term_fb(screen *fb){    munmap(fb->fbmem, fb->w * fb->h * fb->bpp / 8);    return 0;}int generateJPEG(BYTE* data,int w, int h, const char* outfilename)  {  int nComponent = 3;  struct jpeg_compress_struct jcs;  struct jpeg_error_mgr jem;  jcs.err = jpeg_std_error(&jem);   jpeg_create_compress(&jcs);  FILE* f=fopen(outfilename,"wb");  if (f==NULL)   {  free(data);  return 0;  }  jpeg_stdio_dest(&jcs, f);  jcs.image_width = w;   jcs.image_height = h;  jcs.input_components = nComponent;  if (nComponent==1)  jcs.in_color_space = JCS_GRAYSCALE; else   jcs.in_color_space = JCS_RGB;  jpeg_set_defaults(&jcs);      jpeg_set_quality (&jcs, 60, true);  jpeg_start_compress(&jcs, TRUE);  JSAMPROW row_pointer[1];int row_stride;   row_stride = jcs.image_width*nComponent;   while (jcs.next_scanline < jcs.image_height) {  row_pointer[0] = & data[jcs.next_scanline*row_stride];jpeg_write_scanlines(&jcs, row_pointer, 1);  }  jpeg_finish_compress(&jcs);  jpeg_destroy_compress(&jcs);  fclose(f);  return 1;  }  BYTE*  generateRGB24Data()  {  struct {  BYTE r;  BYTE g;  BYTE b;  } pRGB[100][199];memset( pRGB, 0, sizeof(pRGB) ); int i=0, j=0;  for(  i=50;i<70;i++ ){  for( j=70;j<140;j++ ){  pRGB[i][j].b = 0xff;  }  }  for(  i=0;i<10;i++ ){  for( j=0;j<199;j++ ){  pRGB[i][j].r = 0xff;  }  }  BYTE* ret = (BYTE*)malloc(sizeof(BYTE)*100*199*3);  memcpy(ret, (BYTE*)pRGB, sizeof(pRGB));  return ret;  }  int main(void){  int i, j;unsigned char *p;int w, h;//BYTE* data = generateRGB24Data();  screen fb_screen;init_fb(&fb_screen);w = fb_screen.w;h = fb_screen.h;p = (unsigned char *)malloc(w * h * 3);printf("0x%x %x %x %x\n", *fb_screen.fbmem, *(fb_screen.fbmem + 1), \*(fb_screen.fbmem + 2), *(fb_screen.fbmem + 3));for(i = 0; i < h; i++){for(j = 0; j < w; j++){*(p + (i * w + j) * 3) = *(fb_screen.fbmem + (i * w + j) * 4 + 0);*(p + (i * w + j) * 3 + 1) = *(fb_screen.fbmem + (i * w + j) * 4 + 1);*(p + (i * w + j) * 3 + 2) = *(fb_screen.fbmem + (i * w + j) * 4 + 2);}}generateJPEG(p, fb_screen.w, fb_screen.h, "/sdcard/test.jpg");  term_fb(&fb_screen);free(p);//free(data);  return 0;}

Android.mk

LOCAL_PATH:= $(call my-dir)include $(CLEAR_VARS)LOCAL_SRC_FILES:= jtest.cLOCAL_MODULE:= jtest#LOCAL_FORCE_STATIC_EXECUTABLE := true#LOCAL_STATIC_LIBRARIES := libc LOCAL_SHARED_LIBRARIES:= libjpeg libcLOCAL_C_INCLUDES := $(LOCAL_PATH)LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)LOCAL_MODULE_TAGS := debuginclude $(BUILD_EXECUTABLE)

运行后在/sdcard/目录下，生产test.jpg