Saving GDI+ Metafile as BMP cropped when screen scaling not 100% - c++

Question

When saving a bitmap file from a GDI+ metafile object, the output is affected by the current display scale of the monitor.
For example, the following code sample generates these images:
with screen at 100% scaling (81x81 pixel bitmap generated).
with screen at 125% scaling (52x52 pixel bitmap generated).
#include <Windows.h>
// GDI+ libraries
#include <gdiplus.h>
#pragma comment(lib, "gdiplus.lib")
void main()
{
// Startup GDI+
ULONG_PTR gdiplusToken;
Gdiplus::GdiplusStartupInput gdiplusStartupInput;
Gdiplus::GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, nullptr);
{
// Create a metafile
const auto dc = GetDC(nullptr);
const auto cdc = CreateCompatibleDC(dc);
Gdiplus::Metafile metafile{ L"test.emf", cdc };
auto graphics = Gdiplus::Graphics::FromImage(&metafile);
// Draw some things
Gdiplus::SolidBrush yellowBrush{ Gdiplus::Color::Yellow };
graphics->FillRectangle(&yellowBrush, 0, 0, 70, 70);
Gdiplus::SolidBrush redBrush(Gdiplus::Color::Red);
graphics->FillRectangle(&redBrush, 10, 10, 50, 50);
delete graphics; // Must be deleted before saving (is this the correct way?)
// Save as BMP (MIME type: image/bmp)
CLSID bmpEncoderId{1434252288, 6660, 4563, {154, 115, 0, 0, 248, 30, 243, 46}};
auto status = metafile.Save(L"test.bmp", &bmpEncoderId);
// Cleanup
DeleteDC(cdc);
ReleaseDC(nullptr, dc);
}
// Shutdown GDI+
Gdiplus::GdiplusShutdown(gdiplusToken);
}
I've tried adding the following in several places (as suggested in other SO answers) but this doesn't seem to change the behviour.
// Set scaling
Gdiplus::MetafileHeader mfh{};
metafile.GetMetafileHeader(&mfh);
graphics->ScaleTransform(mfh.GetDpiX() / graphics->GetDpiX(),
mfh.GetDpiY() / graphics->GetDpiY());
Is it possible to export the full bitmap image independent of what scaling is set on the monitor?
SOLUTION: This was caused by not compiling as DPI-aware.