1.板子是imx6ullpro，屏幕分辨率是1024600，摄像头的分辨率是800600的，摄像头图像并不能占满全部屏幕。
2.在使用framebuffer后想使用lvgl在右侧生成按钮来控制，比如打开摄像头关闭摄像头，截图或者录屏。
3.问题在于打开摄像头后，摄像头实时图像可以正常显示，按钮没有被覆盖但按钮无法按取。
4.就算强制关闭摄像头后，屏幕上还会留下关闭时的图片。
5.论坛里也有人说用lvgl画布可以显示，但跟着一些回复也没有搞定，很是迷惑
6.以下是代码，通过start按钮打开摄像头
lv_obj_t *back_btn;
lv_obj_t *back_btn_text;
lv_obj_t *screenshot;
lv_obj_t *screenshot_text;
lv_obj_t *screenrecord;
lv_obj_t *screenrecord_text;
lv_obj_t *background_video;
lv_obj_t *start_btn;
lv_obj_t *start_btn_text;
int start_or_stop_flag=0;
lv_obj_t *canvas;
static lv_color_t canvasBuf[(32*800)*600/8];
void video_back_event_cb(lv_event_t *e);
void video_start_event_cb(lv_event_t *e);
void canvas_test(void);
void video_test(void)
{
//background
LV_IMG_DECLARE(white);
background_video=lv_img_create(lv_scr_act());
lv_img_set_src(background_video,&white);
lv_obj_center(background_video);
//back_btn
back_btn=lv_btn_create(lv_scr_act());
lv_obj_set_size(back_btn,150,100);
lv_obj_set_style_bg_color(back_btn,lv_color_hex(0x000000),0);
lv_obj_set_style_bg_opa(back_btn,30,0);
lv_obj_set_style_border_color(back_btn,lv_color_hex(0xffffff),0);
lv_obj_set_pos(back_btn,850,0);
lv_obj_add_event_cb(back_btn,video_back_event_cb,LV_EVENT_ALL,NULL);
back_btn_text=lv_label_create(back_btn);
lv_label_set_text(back_btn_text,LV_SYMBOL_LEFT "Back");
lv_obj_set_style_text_font(back_btn_text,&lv_font_montserrat_30,LV_STATE_DEFAULT);
lv_obj_align(back_btn_text,LV_ALIGN_CENTER,0,0);
// lv_obj_add_event_cb(back_btn_text,video_back_event_cb,LV_EVENT_ALL,NULL);
//start and stop
start_btn=lv_btn_create(lv_scr_act());
lv_obj_set_size(start_btn,150,100);
lv_obj_set_style_bg_color(start_btn,lv_color_hex(0x000000),0);
lv_obj_set_style_bg_opa(start_btn,30,0);
lv_obj_set_style_border_color(start_btn,lv_color_hex(0xffffff),0);
lv_obj_set_pos(start_btn,850,150);
start_btn_text=lv_label_create(start_btn);
lv_label_set_text(start_btn_text,LV_SYMBOL_PLAY "START");
lv_obj_set_style_text_font(start_btn_text,&lv_font_montserrat_30,LV_STATE_DEFAULT);
lv_obj_align(start_btn_text,LV_ALIGN_CENTER,0,0);
lv_obj_add_event_cb(start_btn,video_start_event_cb,LV_EVENT_ALL,NULL);
//screenshot
screenshot=lv_btn_create(lv_scr_act());
lv_obj_set_size(screenshot,150,100);
lv_obj_set_style_bg_color(screenshot,lv_color_hex(0x000000),0);
lv_obj_set_style_bg_opa(screenshot,30,0);
lv_obj_set_style_border_color(screenshot,lv_color_hex(0xffffff),0);
lv_obj_set_pos(screenshot,850,300);
screenshot_text=lv_label_create(screenshot);
lv_label_set_text(screenshot_text,LV_SYMBOL_IMAGE "IMAGE");
lv_obj_set_style_text_font(screenshot_text,&lv_font_montserrat_30,LV_STATE_DEFAULT);
lv_obj_align(screenshot_text,LV_ALIGN_CENTER,0,0);
//screenrecord
screenrecord=lv_btn_create(lv_scr_act());
lv_obj_set_size(screenrecord,150,100);
lv_obj_set_style_bg_color(screenrecord,lv_color_hex(0x000000),0);
lv_obj_set_style_bg_opa(screenrecord,30,0);
lv_obj_set_style_border_color(screenrecord,lv_color_hex(0xffffff),0);
lv_obj_set_pos(screenrecord,850,450);
screenrecord_text=lv_label_create(screenrecord);
lv_label_set_text(screenrecord_text,LV_SYMBOL_VIDEO "VIDEO");
lv_obj_set_style_text_font(screenrecord_text,&lv_font_montserrat_30,LV_STATE_DEFAULT);
lv_obj_align(screenrecord_text,LV_ALIGN_CENTER,0,0);
}
void video_back_event_cb(lv_event_t *e)
{
lv_event_code_t code = lv_event_get_code(e);
lv_obj_t * obj = lv_event_get_target(e);
if(code==LV_EVENT_CLICKED)
{
lv_obj_del(background_video);
//lv_obj_add_flag(file_explorer,LV_OBJ_FLAG_HIDDEN);
lv_obj_del(back_btn_text);
lv_obj_del(back_btn);
lv_obj_del(start_btn);
lv_obj_del(screenrecord);
lv_obj_del(screenshot);
}
}
void video_start_event_cb(lv_event_t *e)
{
lv_event_code_t code = lv_event_get_code(e);
lv_obj_t * obj = lv_event_get_target(e);
if(code==LV_EVENT_CLICKED)
{
if(start_or_stop_flag==0)
{
lv_label_set_text(start_btn_text,LV_SYMBOL_PAUSE "STOP");
lv_obj_set_style_text_font(start_btn_text,&lv_font_montserrat_30,LV_STATE_DEFAULT);
lv_obj_align(start_btn_text,LV_ALIGN_CENTER,0,0);
start_or_stop_flag=1;
}else if(start_or_stop_flag==1)
{
lv_label_set_text(start_btn_text,LV_SYMBOL_PLAY "START");
lv_obj_set_style_text_font(start_btn_text,&lv_font_montserrat_30,LV_STATE_DEFAULT);
lv_obj_align(start_btn_text,LV_ALIGN_CENTER,0,0);
start_or_stop_flag=0;
}
video_show();
}
}
#include "video.h"
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <linux/videodev2.h>
#include <string.h>
#include <sys/mman.h>
#include <linux/fb.h>
#include <stdio.h>
int fd_fb; /* 文件句柄 */
static struct fb_var_screeninfo var; /* LCD可变参数 */
static unsigned int *fb_base = NULL; /* Framebuffer映射基地址 */
static int screen_size; /* 整个Framebuffer大小*/
int lcd_w = 1024 ,lcd_h= 600;
//解码函数
void yuyv_to_rgb(unsigned char *yuyvdata, unsigned char *rgbdata, int w, int h)
{
int r1, g1, b1;
int r2, g2, b2;
for(int i=0; i<w*h/2; i++)
{
char data[4];
memcpy(data, yuyvdata+i*4, 4);
unsigned char Y0=data[0];
unsigned char U0=data[1];
unsigned char Y1=data[2];
unsigned char V1=data[3];
//Y0U0Y1V1 -->[Y0 U0 V1] [Y1 U0 V1]
b1 = Y0+1.4075*(V1-128); if(b1>255)b1=255; if(b1<0)b1=0;
g1 =Y0- 0.3455 * (U0-128) - 0.7169*(V1-128); if(g1>255)g1=255; if(g1<0)g1=0;
r1 = Y0 + 1.779 * (U0-128); if(r1>255)r1=255; if(r1<0)r1=0;
b2 = Y1+1.4075*(V1-128);if(b2>255)b2=255; if(b2<0)b2=0;
g2 = Y1- 0.3455 * (U0-128) - 0.7169*(V1-128); if(g2>255)g2=255; if(g2<0)g2=0;
r2 = Y1 + 1.779 * (U0-128); if(r2>255)r2=255; if(r2<0)r2=0;
rgbdata[i*6+0]=r1;
rgbdata[i*6+1]=g1;
rgbdata[i*6+2]=b1;
rgbdata[i*6+3]=r2;
rgbdata[i*6+4]=g2;
rgbdata[i*6+5]=b2;
}
}
void lcd_show_rgb(unsigned char *rgbdata, int w ,int h)
{
unsigned int *ptr = fb_base; //不要直接对lcd基地址操作以免卡住
for(int i = 0; i <h; i++) {
for(int j = 0; j < w; j++) {
memcpy(ptr+j,rgbdata+j*3,4);//rgb用3个字节表示一个像素点
}
ptr += lcd_w;
rgbdata += w*3;
}
}
int video_show(void)
{
fd_fb = open("/dev/fb0", O_RDWR); //打开LCD文件
if(fd_fb < 0)
{
perror("/dev/fb0");
exit(-1);
}
if (ioctl(fd_fb,FBIOGET_VSCREENINFO,&var)) //读取lcd参数
{
printf("can't get fb_var_screeninfo \n");
goto err1;
}
printf("X:%d Y:%d bbp:%d\n",var.xres,var.yres,var.bits_per_pixel);
screen_size = var.xres *var.yres *var.bits_per_pixel /8; //整个Framebuffer大小，bits_per_pixel 表示色深，除以8表示转换单位字节
//screen_size = 1024 *600 *var.bits_per_pixel /8;
//建立内存映射 方便控制
fb_base = (unsigned int*)mmap(NULL,screen_size,PROT_READ|PROT_WRITE,MAP_SHARED, fd_fb,0);
if(fb_base == NULL)
{
printf("can't mmap Framebuffer\n");
goto err1;
}
int fd = open("/dev/video1",O_RDWR); //打开摄像头节点，请根据自己的摄像头所在节点修改
if (fd < 0)
{
perror("打开设备失败");
return -1;
}
//获取摄像头支持格式 ioctl(文件描述符,命令，与命令对应的结构体)
struct v4l2_format vfmt;
vfmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; //摄像头采集
vfmt.fmt.pix.width = 800; //设置摄像头采集参数，不可以任意设置
vfmt.fmt.pix.height = 600;
vfmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; //设置视频采集格式 ，根据上一步测得
int ret = ioctl(fd,VIDIOC_S_FMT,&vfmt); //写入摄像头参数
if (ret < 0)
{
perror("设置格式失败1");
}
struct v4l2_streamparm Stream_Parm; //定义结构体设置摄像头帧率
memset(&Stream_Parm, 0, sizeof(struct v4l2_streamparm));
Stream_Parm.type=V4L2_BUF_TYPE_VIDEO_CAPTURE;
Stream_Parm.parm.capture.timeperframe.denominator = 15 ; //分母
Stream_Parm.parm.capture.timeperframe.numerator = 1 ; //分子
ret = ioctl(fd,VIDIOC_S_PARM,&Stream_Parm); //写入摄像头帧率
if (ret < 0)
{
perror("设置帧率失败");
}
//以下函数是读取目前摄像头帧率
/* Stream_Parm.type=V4L2_BUF_TYPE_VIDEO_CAPTURE;
ret = ioctl(fd,VIDIOC_G_PARM,&Stream_Parm);
if (ret < 0)
{
perror("获取帧率失败");
}
printf("Frame rate: %u/%u\n",Stream_Parm.parm.capture.timeperframe.numerator,Stream_Parm.parm.capture.timeperframe.denominator);
*/
//申请内核空间
struct v4l2_requestbuffers reqbuffer;
reqbuffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
reqbuffer.count = 4; //申请4个缓冲区
reqbuffer.memory = V4L2_MEMORY_MMAP; //映射方式
ret = ioctl(fd,VIDIOC_REQBUFS,&reqbuffer);
if (ret < 0)
{
perror("申请空间失败");
}
//映射
unsigned char *mptr[4];//保存映射后用户空间的首地址
unsigned int size[4];
struct v4l2_buffer mapbuffer;
//初始化type和index
mapbuffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
for(int i = 0; i <4;i++) {
mapbuffer.index = i;
ret = ioctl(fd,VIDIOC_QUERYBUF,&mapbuffer); //从内核空间中查询一个空间作映射
if (ret < 0)
{
perror("查询内核空间失败");
}
//映射到用户空间
mptr[i] = (unsigned char *)mmap(NULL,mapbuffer.length,PROT_READ|PROT_WRITE,MAP_SHARED,fd,mapbuffer.m.offset);
size[i] = mapbuffer.length; //保存映射长度用于后期释放
//查询后通知内核已经放回
ret = ioctl(fd,VIDIOC_QBUF,&mapbuffer);
if (ret < 0)
{
perror("放回失败");
}
}
//开始采集
int type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
ret = ioctl(fd,VIDIOC_STREAMON,&type);
if (ret < 0)
{
perror("开启失败");
}
lv_obj_t *video_img;
lv_draw_rect_dsc_t my_img_draw_dsc;
//定义一个空间存储解码后的rgb
unsigned char rgbdata[800*600*3];
lv_draw_rect_dsc_init(&my_img_draw_dsc);
static lv_color_t cbuf[LV_CANVAS_BUF_SIZE_INDEXED_1BIT(800,600)];
video_img=lv_canvas_create(lv_scr_act());
while(1)
{
//从队列中提取一帧数据
struct v4l2_buffer readbuffer;
readbuffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; //每个结构体都需要设置type为这个参赛要记住
ret = ioctl(fd,VIDIOC_DQBUF,&readbuffer);
if (ret < 0)
{
perror("读取数据失败");
}
//显示在lcd上
yuyv_to_rgb(mptr[readbuffer.index],rgbdata,800,600);//把jpeg数据解码为rgb数据
lcd_show_rgb(rgbdata,800,600);
//通知内核使用完毕
ret = ioctl(fd, VIDIOC_QBUF, &readbuffer);
if(ret < 0)
{
perror("放回队列失败");
}
}
//停止采集
ret = ioctl(fd,VIDIOC_STREAMOFF,&type);
//释放映射
for(int i=0; i<4; i)munmap(mptr[i], size[i]);
close(fd); //关闭文件
return 0;
err1:
//close(fd_fb);
return -1;
}
7.这是ui图片
