如何拍摄第二个屏幕监视器的屏幕截图? [英] How to take a screenshot of a second screen monitor?
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问题描述
我需要获取第二个屏幕监视器的屏幕截图.我找到了一种截屏的简单方法,但仅适用于主显示器的截屏.这是代码:
I need get a screenshot of a second screen monitor. I found a simple way to make a screen shot, but only works for screen shot of a primary monitor. Here is the code:
#include <windows.h>
void ScreenShot(char*BmpName){
HWND DesktopHwnd = GetDesktopWindow();
RECT DesktopParams;
HDC DevC = GetDC(DesktopHwnd);
GetWindowRect(DesktopHwnd, &DesktopParams);
DWORD Width = DesktopParams.right - DesktopParams.left;
DWORD Height = DesktopParams.bottom - DesktopParams.top;
DWORD FileSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + (sizeof(RGBTRIPLE) + 1 * (Width*Height * 4));
char *BmpFileData = (char*)GlobalAlloc(0x0040, FileSize);
PBITMAPFILEHEADER BFileHeader = (PBITMAPFILEHEADER)BmpFileData;
PBITMAPINFOHEADER BInfoHeader = (PBITMAPINFOHEADER)&BmpFileData[sizeof(BITMAPFILEHEADER)];
BFileHeader->bfType = 0x4D42; // BM
BFileHeader->bfSize = sizeof(BITMAPFILEHEADER);
BFileHeader->bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
BInfoHeader->biSize = sizeof(BITMAPINFOHEADER);
BInfoHeader->biPlanes = 1;
BInfoHeader->biBitCount = 24;
BInfoHeader->biCompression = BI_RGB;
BInfoHeader->biHeight = Height;
BInfoHeader->biWidth = Width;
RGBTRIPLE *Image = (RGBTRIPLE*)&BmpFileData[sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)];
RGBTRIPLE color;
HDC CaptureDC = CreateCompatibleDC(DevC);
HBITMAP CaptureBitmap = CreateCompatibleBitmap(DevC, Width, Height);
SelectObject(CaptureDC, CaptureBitmap);
BitBlt(CaptureDC, 0, 0, Width, Height, DevC, 0, 0, SRCCOPY | CAPTUREBLT);
GetDIBits(CaptureDC, CaptureBitmap, 0, Height, Image, (LPBITMAPINFO)BInfoHeader, DIB_RGB_COLORS);
DWORD Junk;
HANDLE FH = CreateFileA(BmpName, GENERIC_WRITE, FILE_SHARE_WRITE, 0, CREATE_ALWAYS, 0, 0);
WriteFile(FH, BmpFileData, FileSize, &Junk, 0);
CloseHandle(FH);
GlobalFree(BmpFileData);
}
int main()
{
ScreenShot("Hello.bmp");
}
但这仅拍摄默认监视器的屏幕截图.
But this take a screen shot only of the default monitor.
如果处于演示模式,则需要使用2台显示器拍摄第二台显示器的屏幕截图.
If has in presentation mode, with 2 monitors I need to take a screen shot of a second monitor.
我尝试在
EnumDisplayMonitors
像这样:
#include <windows.h>
BOOL CALLBACK MonitorEnumProcCallback(_In_ HMONITOR hMonitor, _In_ HDC DevC, _In_ LPRECT lprcMonitor, _In_ LPARAM dwData) {
screenCounter++;
char*BmpName;
if (screenCounter == 1){
BmpName = "1 screen.bmp";
}
else {
BmpName = "2 screen.bmp";
}
MONITORINFO info;
info.cbSize = sizeof(MONITORINFO);
BOOL monitorInfo = GetMonitorInfo(hMonitor, &info);
if (monitorInfo) {
DWORD Width = info.rcMonitor.right - info.rcMonitor.left;
DWORD Height = info.rcMonitor.bottom - info.rcMonitor.top;
DWORD FileSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + (sizeof(RGBTRIPLE) + 1 * (Width*Height * 4));
char *BmpFileData = (char*)GlobalAlloc(0x0040, FileSize);
PBITMAPFILEHEADER BFileHeader = (PBITMAPFILEHEADER)BmpFileData;
PBITMAPINFOHEADER BInfoHeader = (PBITMAPINFOHEADER)&BmpFileData[sizeof(BITMAPFILEHEADER)];
BFileHeader->bfType = 0x4D42; // BM
BFileHeader->bfSize = sizeof(BITMAPFILEHEADER);
BFileHeader->bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
BInfoHeader->biSize = sizeof(BITMAPINFOHEADER);
BInfoHeader->biPlanes = 1;
BInfoHeader->biBitCount = 24;
BInfoHeader->biCompression = BI_RGB;
BInfoHeader->biHeight = Height;
BInfoHeader->biWidth = Width;
RGBTRIPLE *Image = (RGBTRIPLE*)&BmpFileData[sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)];
RGBTRIPLE color;
HDC CaptureDC = CreateCompatibleDC(DevC);
HBITMAP CaptureBitmap = CreateCompatibleBitmap(DevC, Width, Height);
SelectObject(CaptureDC, CaptureBitmap);
BitBlt(CaptureDC, 0, 0, Width, Height, DevC, 0, 0, SRCCOPY | CAPTUREBLT);
GetDIBits(CaptureDC, CaptureBitmap, 0, Height, Image, (LPBITMAPINFO)BInfoHeader, DIB_RGB_COLORS);
DWORD Junk;
HANDLE FH = CreateFileA(BmpName, GENERIC_WRITE, FILE_SHARE_WRITE, 0, CREATE_ALWAYS, 0, 0);
WriteFile(FH, BmpFileData, FileSize, &Junk, 0);
CloseHandle(FH);
GlobalFree(BmpFileData);
}
return TRUE;
}
int main() {
EnumDisplayMonitors(NULL, NULL, MonitorEnumProcCallback, 0);
return 0;
}
但是这又给了我两个黑色图像.
but this return to me two black images.
推荐答案
感谢@Hans Passant的帮助.
Thanks for help @Hans Passant.
我更改了左上角的值
但是我犯了另一个错误,我在EnumDisplayMonitors中为第一个参数发送了NULL.
But I made another mistake, I send NULL in the EnumDisplayMonitors for the first argument.
以下是更改:
BOOL CALLBACK MonitorEnumProcCallback(_In_ HMONITOR hMonitor, _In_ HDC DevC, _In_ LPRECT lprcMonitor, _In_ LPARAM dwData) {
screenCounter++;
char*BmpName;
if (screenCounter == 1){
BmpName = "1 screen.bmp";
}
else {
BmpName = "2 screen.bmp";
}
MONITORINFO info;
info.cbSize = sizeof(MONITORINFO);
BOOL monitorInfo = GetMonitorInfo(hMonitor, &info);
if (monitorInfo) {
DWORD Width = info.rcMonitor.right - info.rcMonitor.left;
DWORD Height = info.rcMonitor.bottom - info.rcMonitor.top;
DWORD FileSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + (sizeof(RGBTRIPLE) + 1 * (Width*Height * 4));
char *BmpFileData = (char*)GlobalAlloc(0x0040, FileSize);
PBITMAPFILEHEADER BFileHeader = (PBITMAPFILEHEADER)BmpFileData;
PBITMAPINFOHEADER BInfoHeader = (PBITMAPINFOHEADER)&BmpFileData[sizeof(BITMAPFILEHEADER)];
BFileHeader->bfType = 0x4D42; // BM
BFileHeader->bfSize = sizeof(BITMAPFILEHEADER);
BFileHeader->bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
BInfoHeader->biSize = sizeof(BITMAPINFOHEADER);
BInfoHeader->biPlanes = 1;
BInfoHeader->biBitCount = 24;
BInfoHeader->biCompression = BI_RGB;
BInfoHeader->biHeight = Height;
BInfoHeader->biWidth = Width;
RGBTRIPLE *Image = (RGBTRIPLE*)&BmpFileData[sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER)];
RGBTRIPLE color;
HDC CaptureDC = CreateCompatibleDC(DevC);
HBITMAP CaptureBitmap = CreateCompatibleBitmap(DevC, Width, Height);
SelectObject(CaptureDC, CaptureBitmap);
BitBlt(CaptureDC, 0, 0, Width, Height, DevC, info.rcMonitor.left, info.rcMonitor.top, SRCCOPY | CAPTUREBLT);
GetDIBits(CaptureDC, CaptureBitmap, 0, Height, Image, (LPBITMAPINFO)BInfoHeader, DIB_RGB_COLORS);
DWORD Junk;
HANDLE FH = CreateFileA(BmpName, GENERIC_WRITE, FILE_SHARE_WRITE, 0, CREATE_ALWAYS, 0, 0);
WriteFile(FH, BmpFileData, FileSize, &Junk, 0);
CloseHandle(FH);
GlobalFree(BmpFileData);
}
return TRUE;
}
int main() {
HDC DevC = GetDC(NULL);
BOOL b = EnumDisplayMonitors(DevC, NULL, MonitorEnumProcCallback, 0);
return 0;
}
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