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#pragma once
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#include <Windows.h>
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#include <opencv2/opencv.hpp>
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class Screenshot
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{
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public:
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    Screenshot();
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    double static getZoom();
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    cv::Mat getScreenshot();
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    cv::Mat getScreenshot(int x, int y, int width, int height);
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private:
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    int m_width;
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    int m_height;
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    HDC m_screenDC;
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    HDC m_compatibleDC;
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    HBITMAP m_hBitmap;
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    LPVOID m_screenshotData = nullptr;
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};

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#include "Screenshot.h"
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using cv::Mat;
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Screenshot::Screenshot()
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{
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    double zoom = getZoom();
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    m_width = GetSystemMetrics(SM_CXSCREEN) * zoom;
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    m_height = GetSystemMetrics(SM_CYSCREEN) * zoom;
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    m_screenshotData = new char[m_width * m_height * 4];
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    memset(m_screenshotData, 0, m_width);
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    // 获取屏幕 DC
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    m_screenDC = GetDC(NULL);
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    m_compatibleDC = CreateCompatibleDC(m_screenDC);
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    // 创建位图
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    m_hBitmap = CreateCompatibleBitmap(m_screenDC, m_width, m_height);
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    SelectObject(m_compatibleDC, m_hBitmap);
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}
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/* 获取整个屏幕的截图 */
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Mat Screenshot::getScreenshot()
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{
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    // 得到位图的数据
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    BitBlt(m_compatibleDC, 0, 0, m_width, m_height, m_screenDC, 0, 0, SRCCOPY);
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    GetBitmapBits(m_hBitmap, m_width * m_height * 4, m_screenshotData);
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    // 创建图像
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    Mat screenshot(m_height, m_width, CV_8UC4, m_screenshotData);
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    return screenshot;
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}
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/** @brief 获取指定范围的屏幕截图
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 * @param x 图像左上角的 X 坐标
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 * @param y 图像左上角的 Y 坐标
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 * @param width 图像宽度
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 * @param height 图像高度
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 */
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Mat Screenshot::getScreenshot(int x, int y, int width, int height)
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{
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    Mat screenshot = getScreenshot();
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    return screenshot(cv::Rect(x, y, width, height));
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}
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/* 获取屏幕缩放值 */
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double Screenshot::getZoom()
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{
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    // 获取窗口当前显示的监视器
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    HWND hWnd = GetDesktopWindow();
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    HMONITOR hMonitor = MonitorFromWindow(hWnd, MONITOR_DEFAULTTONEAREST);
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    // 获取监视器逻辑宽度
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    MONITORINFOEX monitorInfo;
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    monitorInfo.cbSize = sizeof(monitorInfo);
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    GetMonitorInfo(hMonitor, &monitorInfo);
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    int cxLogical = (monitorInfo.rcMonitor.right - monitorInfo.rcMonitor.left);
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    // 获取监视器物理宽度
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    DEVMODE dm;
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    dm.dmSize = sizeof(dm);
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    dm.dmDriverExtra = 0;
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    EnumDisplaySettings(monitorInfo.szDevice, ENUM_CURRENT_SETTINGS, &dm);
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    int cxPhysical = dm.dmPelsWidth;
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    return cxPhysical * 1.0 / cxLogical;
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}