spdis
112 lines
3.1 KiB
C++
112 lines
3.1 KiB
C++
/*
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* screenshot_demo — 摄像头截图保存
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* ======================================
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* 每次运行截一张图, 保存到 ./screenshot/image_N.jpg
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* 用法:
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* ./screenshot_demo 截一张图 + LCD 显示
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* ./screenshot_demo --no-display 无 LCD
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*/
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#include <opencv2/opencv.hpp>
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#include <iostream>
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#include <cstdio>
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#include <cstring>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/mman.h>
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#include <sys/ioctl.h>
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#include <linux/fb.h>
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using namespace cv;
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using namespace std;
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static uint16_t rgb565(uint8_t r, uint8_t g, uint8_t b)
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{
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return ((r & 0xF8) << 8) | ((g & 0xFC) << 3) | (b >> 3);
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}
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int main(int argc, char *argv[])
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{
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bool no_display = false;
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for (int i = 1; i < argc; ++i)
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if (strcmp(argv[i], "--no-display") == 0)
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no_display = true;
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// ---- 创建目录 ----
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mkdir("./screenshot", 0755);
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// ---- 摄像头 ----
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VideoCapture cap;
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cap.open(0, CAP_V4L2);
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if (!cap.isOpened()) cap.open(0);
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if (!cap.isOpened()) { cerr << "无法打开摄像头" << endl; return 1; }
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cap.set(CAP_PROP_FRAME_WIDTH, 640);
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cap.set(CAP_PROP_FRAME_HEIGHT, 480);
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cap.set(CAP_PROP_FOURCC, VideoWriter::fourcc('M', 'J', 'P', 'G'));
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printf("摄像头: %dx%d\n",
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(int)cap.get(CAP_PROP_FRAME_WIDTH),
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(int)cap.get(CAP_PROP_FRAME_HEIGHT));
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// ---- 丢弃前几帧 (曝光稳定) ----
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Mat frame;
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for (int i = 0; i < 10; ++i)
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cap.read(frame);
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usleep(100000);
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// ---- 截图 ----
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if (!cap.read(frame) || frame.empty())
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{
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cerr << "截图失败" << endl;
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cap.release();
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return 1;
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}
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// 自增文件名
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int idx = 0;
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char fname[64];
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struct stat st;
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do {
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snprintf(fname, sizeof(fname),
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"./screenshot/image_%05d.jpg", ++idx);
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} while (stat(fname, &st) == 0);
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imwrite(fname, frame);
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printf("截图: %s (%dx%d)\n", fname, frame.cols, frame.rows);
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// ---- LCD 显示 ----
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if (!no_display)
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{
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int fb_fd = open("/dev/fb0", O_RDWR);
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if (fb_fd >= 0)
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{
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struct fb_var_screeninfo vinfo;
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ioctl(fb_fd, FBIOGET_VSCREENINFO, &vinfo);
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int scr_w = vinfo.xres, scr_h = vinfo.yres;
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size_t fb_size = vinfo.yres_virtual * vinfo.xres_virtual * 2;
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uint16_t *fb_buf = (uint16_t *)mmap(nullptr, fb_size,
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PROT_READ|PROT_WRITE,
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MAP_SHARED, fb_fd, 0);
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Mat disp;
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resize(frame, disp, Size(scr_w, scr_h));
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rectangle(disp, Point(0, 0), Point(disp.cols, disp.rows),
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Scalar(0, 255, 255), 3);
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for (int y = 0; y < scr_h; ++y)
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for (int x = 0; x < scr_w; ++x)
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{
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Vec3b px = disp.at<Vec3b>(y, x);
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fb_buf[y * scr_w + x] = rgb565(px[2], px[1], px[0]);
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}
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sleep(1);
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munmap(fb_buf, fb_size);
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close(fb_fd);
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}
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}
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cap.release();
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return 0;
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}
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