Win32: BITMAP to ID2D1Bitmap

Question

Win32: BITMAP to ID2D1Bitmap

thebluetropics 1,046

How can I get ID2D1Bitmap from a BITMAP in Win32/Direct2D?

   HDC hScreenDC = GetDC(nullptr);  
   HDC hMemoryDC = CreateCompatibleDC(hScreenDC);  
   state.sw = GetDeviceCaps(hScreenDC, HORZRES);  
   state.sh = GetDeviceCaps(hScreenDC, VERTRES);  
   HBITMAP hBitmap = CreateCompatibleBitmap(hScreenDC, state.sw, state.sh);  
   HBITMAP hOldBitmap = static_cast<HBITMAP>(SelectObject(hMemoryDC, hBitmap));  
   BitBlt(hMemoryDC, 0, 0, state.sw, state.sh, hScreenDC, 0, 0, SRCCOPY);  
   hBitmap = static_cast<HBITMAP>(SelectObject(hMemoryDC, hOldBitmap));  
   DeleteDC(hMemoryDC);  
   DeleteDC(hScreenDC);  
     
   BITMAP bmp;  
   GetObject(hBitmap, sizeof(BITMAP), reinterpret_cast<void*>(&bmp));  
     
   ID2D1Bitmap* d2dBitmap = bmp; // Somehow do this

I have trouble finding the tutorial for this. So I ended up here.

Regards, @thebluetropics

Accepted answer

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Answer 1

Castorix31 90,521

GetDIBits + ID2D1RenderTarget::CreateBitmap from lpvBits

thebluetropics 1,046 Reputation points

2022-09-30T09:15:19.003+00:00

@Castorix31

What is HDC should be? Somehow, I got confused about this. There is two variable that maybe match this (see my code above): hScreenDC, hMemoryDC
But what if there is somehow only BITMAP are available and nothing such HDC?
Castorix31 90,521 Reputation points

2022-09-30T09:41:48.093+00:00

The DC where the hBitmap is selected (in your case, hMemoryDC)
thebluetropics 1,046 Reputation points

2022-09-30T12:02:14.613+00:00

Is there any other way, like get the HDC from only a BITMAP?

The hMemoryDC, as you can see, it was deleted by DeleteDC()
Castorix31 90,521 Reputation points

2022-09-30T12:10:12.617+00:00

You must call GetDIBits before DeleteDC (I tested with your code and I get a correct ID2D1Bitmap, containing a copy of the screen DC)
thebluetropics 1,046 Reputation points

2022-09-30T12:48:23.85+00:00

How do you do GetDIBits()? If possible, can you show me the tested code?
I have no idea with the remaining parameters, start and total of scanlines, etc

Castorix31 90,521

The quick test I did from your code =>

HDC hScreenDC = GetDC(nullptr);  
HDC hMemoryDC = CreateCompatibleDC(hScreenDC);	  
int nCX = GetDeviceCaps(hScreenDC, HORZRES);  
int nCY = GetDeviceCaps(hScreenDC, VERTRES);  
HBITMAP hBitmap = CreateCompatibleBitmap(hScreenDC, nCX, nCY);  
HBITMAP hOldBitmap = static_cast<HBITMAP>(SelectObject(hMemoryDC, hBitmap));  
BitBlt(hMemoryDC, 0, 0, nCX, nCY, hScreenDC, 0, 0, SRCCOPY);  
BITMAP bmp;  
GetObject(hBitmap, sizeof(BITMAP), reinterpret_cast<void*>(&bmp));  
int nWidth = bmp.bmWidth;  
int nHeight = bmp.bmHeight;  
  
BITMAPINFO bmi = { {sizeof(BITMAPINFOHEADER), nWidth, -nHeight, 1, 32, BI_RGB} };  
DWORD* pBits = new DWORD[nWidth * nHeight];  
if (GetDIBits(hMemoryDC, hBitmap, 0, nHeight, pBits, &bmi, DIB_RGB_COLORS))  
{  
	unsigned int nDPI = GetDpiForSystem();  
	D2D1_SIZE_U sizeu = D2D1::SizeU(nWidth, nHeight);  
	D2D1_BITMAP_PROPERTIES props = D2D1::BitmapProperties(  
		D2D1::PixelFormat(  
			DXGI_FORMAT_B8G8R8A8_UNORM,  
			D2D1_ALPHA_MODE_IGNORE  
		),  
		nDPI,  
		nDPI  
	);  
	ID2D1Bitmap* d2dBitmap = NULL;  
	// m_pD2DDeviceContext3 is ID2D1DeviceContext3*  
	hr = m_pD2DDeviceContext3->CreateBitmap(sizeu, pBits, 4 * nWidth, &props, &d2dBitmap);  
	// d2dBitmap is OK here (tested with m_pD2DDeviceContext3->DrawBitmap)  
}  
SelectObject(hMemoryDC, hOldBitmap);  
DeleteObject(hBitmap);  
DeleteDC(hMemoryDC);  
DeleteDC(hScreenDC);

thebluetropics 1,046 Reputation points

2022-09-30T22:56:45.457+00:00

@Castorix31

Thank you for the example. May I know why do you put SelectObject(hMemoryDC, hOldBitmap) at the end?
Castorix31 90,521 Reputation points

2022-09-30T23:33:47.38+00:00

Because a GDI object (here hBitmap) must not be deleted while it is still selected into a DC.
thebluetropics 1,046 Reputation points

2022-09-30T23:38:14.817+00:00

@Castorix31

I have tried using DrawBitmap() but the entire client area is black?

Full code
Castorix31 90,521 Reputation points

2022-10-01T00:19:51.847+00:00

Your CreateBitmap is wrong : not created from pBits...
thebluetropics 1,046 Reputation points

2022-10-01T00:24:53.217+00:00

It works as expected, thank you for helping me, @Castorix31

Answer 2

Xiaopo Yang - MSFT 12,731 Microsoft External Staff

Hello @thebluetropics ,
You can load a Bitmap based on decoder's implementation. For an example, see How to Load a Bitmap from a File , How to Load a Bitmap from a Resource (Direct2D).
In order to load a Bitmap, you can try GUID_ContainerFormatBmp.

thebluetropics 1,046 Reputation points

2022-09-30T09:18:45.043+00:00

Hi, @XiaopaoYang-MSFT

Thank you for the answer. However, I am don't mean to load a bitmap from a file. In my code, there is already a BITMAP available to be used. However, In Direct2D methods (e.g DrawBitmap()) only accept ID2D1Bitmap.

Long story short, I need a way to get ID2D1Bitmap from BITMAP.

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Win32: BITMAP to ID2D1Bitmap

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