Easy color picker implementation

colorpicker.cpp

#include <stdio.h>
#include <windows.h>
#include <ShellScalingAPI.h>

#pragma comment(lib,"gdi32.lib")
#pragma comment(lib,"user32.lib")
#pragma comment(lib,"shcore.lib")


int main()
{
	SetProcessDpiAwareness(PROCESS_PER_MONITOR_DPI_AWARE);
	auto hdc = GetDC(0);

	for (;;)
	{
		Sleep(300);
		POINT pt;
		GetCursorPos(&pt);

		const int w = 1;
		const int h = 1;
		BYTE* pBits;
		BITMAPINFOHEADER bih;
		ZeroMemory(&bih, sizeof(bih));
		bih.biSize = sizeof(bih);
		bih.biWidth = w;
		bih.biHeight = -h;
		bih.biPlanes = 1;
		bih.biBitCount = 24;
		bih.biCompression = BI_RGB;
		auto bmp = CreateDIBSection(hdc, (BITMAPINFO*)&bih, DIB_RGB_COLORS, (void**)&pBits, NULL, 0);

		auto hdcMem = CreateCompatibleDC(hdc);
		auto oldBmp = SelectObject(hdcMem, bmp);

		BitBlt(hdcMem, 0, 0, w, h, hdc, pt.x, pt.y, SRCCOPY);

		SelectObject(hdcMem, oldBmp);
		DeleteDC(hdcMem);

		printf("(%d,%d): #%02X%02X%02X\n",
			pt.x, pt.y, pBits[2], pBits[1], pBits[0]);
	}
	ReleaseDC(0, hdc);
}