Given just a HBITMAP, how to draw to it? - c++

Question

I'm an absolute beginner at this but have managed to blunder my way to 93% of where I want to be. Need help for the final 7%.
I've manually created a bitmap like so:
BITMAPINFO bmpInfo = { 0 };
BITMAPINFOHEADER bmpInfoHeader = { 0 };
BITMAP ImageBitmap;
void *bits;
bmpInfoHeader.biSize = sizeof(BITMAPINFOHEADER);
bmpInfoHeader.biBitCount = 32;
bmpInfoHeader.biClrImportant = 0;
bmpInfoHeader.biClrUsed = 0;
bmpInfoHeader.biCompression = BI_RGB;
bmpInfoHeader.biHeight = -IMAGE_DISPLAY_HEIGHT;
bmpInfoHeader.biWidth = IMAGE_DISPLAY_WIDTH;
bmpInfoHeader.biPlanes = 1;
bmpInfoHeader.biSizeImage = IMAGE_DISPLAY_WIDTH * IMAGE_DISPLAY_HEIGHT * 4;
ZeroMemory(&bmpInfo, sizeof(bmpInfo));
bmpInfo.bmiHeader = bmpInfoHeader;
bmpInfo.bmiColors->rgbBlue = 0;
bmpInfo.bmiColors->rgbGreen = 0;
bmpInfo.bmiColors->rgbRed = 0;
bmpInfo.bmiColors->rgbReserved = 0;
g_hImageBitmap = CreateDIBSection(hDC, &bmpInfo, DIB_RGB_COLORS, &bits, NULL, 0);
GetObject(g_hImageBitmap, sizeof(BITMAP), &ImageBitmap);
for (i = 0; i < IMAGE_DISPLAY_WIDTH; i++) {
for (j = 0; j < IMAGE_DISPLAY_HEIGHT; j++) {
((unsigned char *)bits)[j*IMAGE_DISPLAY_WIDTH * 4 + i * 4] = 255; // Blue
((unsigned char *)bits)[j*IMAGE_DISPLAY_WIDTH * 4 + i * 4 + 1] = 255; // Green
((unsigned char *)bits)[j*IMAGE_DISPLAY_WIDTH * 4 + i * 4 + 2] = 255; // Red
((unsigned char *)bits)[j*IMAGE_DISPLAY_WIDTH * 4 + i * 4 + 3] = 0;
}
}
g_ImageBitmapPixels = bits;
and elsewhere WM_PAINT handles drawing this like so
hdc = BeginPaint(hwnd, &ps);
if (g_hImageBitmap != NULL) {
GetObject(g_hImageBitmap, sizeof(BITMAP), &bm);
hOldBitmap = (HBITMAP)SelectObject(hMemoryDC, g_hImageBitmap);
BitBlt(hdc, UPPER_LEFT_IMAGE_X, UPPER_LEFT_IMAGE_Y,
bm.bmWidth, bm.bmHeight, hMemoryDC, 0, 0, SRCCOPY);
SelectObject(hMemoryDC, hOldBitmap);
}
Given the global variable g_ImageBitmapPixels other parts of the program can change and manipulate individual pixels in the bitmap, and when that happens, I use
InvalidateRect(hwnd, &RECT_ImageUpdate_Window, TRUE);
UpdateWindow(hwnd);
to update just that little portion of the screen. Works great. Hooray for me.
To get to the point, my question is, if a function has ONLY the HBITMAP (g_hImageBitmap) ... is there a way to call the Windows library functions to draw lines, text, circles, filled circles, to the HBITMAP? Like these functions
MoveToEx(hDC, x1, y1, NULL);
LineTo(hDC, x2, y2 );
HBRUSH hRedBrush = CreateSolidBrush(RGB(255, 0, 0));
FillRect(hDC, &somerectangle, hRedBrush);
except instead of needing a device context, they just take the HBITMAP?
I have a pointer to the actual pixels (g_ImageBitmapPixels) so I could just write my own line drawing, circle drawing, rectangle filling functions. Indeed I have done that, but it seems a shame not to use the functions Microsoft so kindly provides. Also, I'm not smart enough to make my own text-drawing functions.
Thank you for your help.