Retrieve Physical Font Data from Logical Font Handle - winapi

Question

I wrote a font parser and renderer based on some functionality in the freetype library, but it currently only works for font files that I specify. I'd like to be able to retrieve fonts from the Windows Font Mapper and then parse and render them, but I can't figure out how to get the actual font data from a logical font.
I thought that the easy way to accomplish this would be to get the font file name from the logical font, but based on other stack overflow posts, there isn't any good solution to this because there isn't a 1 to 1 mapping of physical fonts to the logical font you specify.
This code shows how I'm currently retrieving a handle to a logical font:
HFONT windowsFont = CreateFontA(72, 0, 0, 0, 0,
0, 0, 0, ANSI_CHARSET,
OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
DEFAULT_QUALITY, DEFAULT_PITCH, "Arial");
HDC deviceContext = GetDC(windowHandle);
SelectObject(deviceContext, windowsFont);
DWORD fontSize = GetFontData(deviceContext, 0, 0, NULL, 0);
void *fontData = malloc(fontSize);
fontSize = GetFontData(deviceContext, 0, 0, fontData, 0);
char *fontFileData;
size_t fontFileSize;
// This is a function that I wrote that does what you'd expect. It opens
// a file, reads all the bytes to a buffer and closes the file
readFileToBuff(&fontFileData, &fontFileSize, "c:/windows/fonts/arial.ttf");
assert(fontFileSize == fontSize); // This passes
assert(((char)fontFileData) == ((char)fontData)); // This fails
Based on this stack overflow post which is for Java, I'm thinking that what I want to do may not be possible. It seems that the only solution may be to look at all the system font files and try to figure out what they are.
How to get ttf font data from system fonts in java
This surprises me though, because it seems that it would be relatively common for a program to want to render fonts themselves, without relying on the Windows renderer. Does anyone know of a way to get the font data, or how other people have solved this problem?

Answer 1

I don't understand why it's getting the exact same amount of bytes as
the file, but the data isn't the same.
From the official sample, I found the correct way to use GetFontData.
This is the modified code, and the returned data is the same as fontFileData.
HRESULT hr = S_OK;
LPVOID ptr = NULL;
HGLOBAL hGlobal = NULL;
...
HFONT windowsFont = CreateFontA(72, 0, 0, 0, 0,
0, 0, 0, ANSI_CHARSET,
OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
DEFAULT_QUALITY, DEFAULT_PITCH, "Arial");
HDC deviceContext = GetDC(hWnd);
SelectObject(deviceContext, windowsFont);
DWORD fontSize = GetFontData(deviceContext, 0, 0, NULL, 0);
hGlobal = GlobalAlloc(GMEM_MOVEABLE, fontSize);
ptr = GlobalLock(hGlobal);
if (!ptr)
{
hr = HRESULT_FROM_WIN32(GetLastError());
fwprintf(stderr, L"ERROR: Could not lock global memory object: %08X\n", hr);
}
else
{
if (GetFontData(deviceContext, 0, 0, ptr, fontSize) == GDI_ERROR)
{
fwprintf(stderr, L"ERROR: Could not get font data\n");
hr = E_UNEXPECTED;
}
GlobalUnlock(hGlobal);
}
char *fontFileData;
size_t fontFileSize;
// This is a function that I wrote that does what you'd expect. It opens
// a file, reads all the bytes to a buffer and closes the file
readFileToBuff(&fontFileData, &fontFileSize, "c:/windows/fonts/arial.ttf");
assert(fontFileSize == fontSize); // This passes
assert(((char)fontFileData) == ((char)fontData)); // This fails