如何使用GDIPLUS绘制第二台显示器 [英] How to draw over second monitor with GDIPLUS

问题描述

我想在桌面上绘制一些文字和线条。



我正在使用gdiplus.h来创建具有DrawString功能的打印文本。 />


但是它只能在主屏幕显示器上打印文字。



如果有演示模式，有2个显示器我需要在第二台显示器上打印文本。

I'm want to draw some text and lines over the desktop.

I'm using gdiplus.h for print texts with the function DrawString.

But its only print text on a primary screen monitor.

If has in presentation mode, with 2 monitors I need to print text in a second monitor.

#define _WIN32_WINNT 0x500
#include <windows.h>
#include <gdiplus.h>

using namespace Gdiplus;

#pragma comment (lib,"Gdiplus.lib")

int main() {

    HWND desktop = GetDesktopWindow();
    HDC hdc = GetWindowDC(desktop); 

    ULONG_PTR m_gdiplusToken;
    // Initialize GDI+
    GdiplusStartupInput gdiplusStartupInput;
    GdiplusStartup(&m_gdiplusToken, &gdiplusStartupInput, NULL);

    while (true)
    {

        HPEN newpen;
        LPPOINT point = NULL;
        newpen = CreatePen(PS_COSMETIC, 20, RGB(255, 0, 0));
        SelectObject(hdc, newpen);
        MoveToEx(hdc, 1500, 500, point);
        LineTo(hdc, 1600, 550 ); 
        //this block works for draw line in second monitor

        TextOut(hdc, 1500, 300, TEXT("Text of text out"), 17); // this works too


    //But if I'm use gdiplus only print things on the primary screen
    Gdiplus::Graphics g(hdc);

    Pen      pen(Gdiplus::Color(0, 0, 255), 2);

    g.DrawLine(&pen, 1500, 0, 1700, 600);// dont work

    g.DrawLine(&pen, 0, 0, 1200, 600);//  work, but is in the primary screen

    FontFamily  fontFamily(L"Times New Roman");
    Font        font(&fontFamily, 24, FontStyleRegular, UnitPixel);
    SolidBrush  brush(Color(255, 0, 0, 255));

    g.DrawString(TEXT("test of GDI+"), 13, &font, PointF(1600.0f, 300.0f), &brush); // dont work

    g.DrawString(TEXT("test of GDI+"), 13, &font, PointF(500.0f, 300.0f), &brush); // work, but is in the primary screen
    }

    Gdiplus::GdiplusShutdown(m_gdiplusToken);

    return 0;
}

推荐答案

this（多个监视器上的设备上下文） [ ^ ]可能有用

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