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Asked: 2026-06-13T19:21:38+00:00

I’m trying to render a bitmap using both Gdi and Direct 2D on a

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I’m trying to render a bitmap using both Gdi and Direct 2D on a compatible render target.
I create the compatible target with D2D1_COMPATIBLE_RENDER_TARGET_OPTIONS_GDI_COMPATIBLE option and then I do as follows:

HDC hdc=NULL;
ID2D1GdiInteropRenderTarget *gdiTarget=NULL;
target->QueryInterface(__uuidof(ID2D1GdiInteropRenderTarget), (void**)&gdiTarget);
target.BeginDraw();
HRESULT hr=gdiTarget->GetDC(D2D1_DC_INITIALIZE_MODE_CLEAR, &hdc);
if(SUCCEEDED(hr))
{
    /* Gdi drawing code(hdc)*/

gdiTarget->ReleaseDC(NULL);
}
/* Direct2D drawing code
target->EndDraw();
gdiTarget->Release();

But it seems that something goes wrong, because every time I call this render method I get many GDI objects leaks. I try doing this too:

HDC hdc=NULL;
ID2D1GdiInteropRenderTarget *gdiTarget=NULL;
target->QueryInterface(__uuidof(ID2D1GdiInteropRenderTarget), (void**)&gdiTarget);
target.BeginDraw();
HRESULT hr=gdiTarget->GetDC(D2D1_DC_INITIALIZE_MODE_CLEAR, &hdc);
if(SUCCEEDED(hr))
gdiTarget->ReleaseDC(NULL);
target->EndDraw();
gdiTarget->Release();

and i get leaks as well.
I also try with DeleteDC() or ReleaseDC() on HDC created by ID2D1GdiInteropRenderTarget but have no success.

Any suggestion?
Thanks in advance!

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1 Answer

  1. Editorial Team

    I found the problem. It was a not released d2dBitmap that sometimes caused memory leaks, and, when I tried to release the ID2D1GdiInteropRenderTarget, it caused Gdi object leaks.

    HDC hdc=NULL;
ID2D1GdiInteropRenderTarget *gdiTarget=NULL;
compatibleTarget->QueryInterface(__uuidof(ID2D1GdiInteropRenderTarget),(void**)&gdiTarget);
compatibleTarget.BeginDraw();
HRESULT hr=gdiTarget->GetDC(D2D1_DC_INITIALIZE_MODE_CLEAR, &hdc);
if(SUCCEEDED(hr))
{
    /* Gdi drawing code(hdc)*/

gdiTarget->ReleaseDC(NULL);
}
/* Direct2D drawing code
compatibleTarget->EndDraw();
gdiTarget->Release();
ID2D1Bitmap *bitmap=NULL;
compatibleTarget->GetBitmap(&bitmap);
target->BeginDraw();
target->DrawBitmap(bitmap);
target->EndDraw();
compatibleTarget->Release();    // I thought this only enough
bitmap->Release();              // This solved the problem

    I’m still a little confused about which type of target is better to use (DC or Hwnd), because I found different performance depending on whether or not I used the Gpu.
    In particular, I found the following problems:

    • If I use the DCRenderTarget I can not use hardware acceleration (or Default), because I have continued violations of protected areas of memory. This does not happen if I use HwndRenderTarget.
    • If I use HwndRenderTarget, in general everything is fine, but I lose the focus on the window, which does not recognize the KeyPressed message, and, if I use the Gpu, performance fall a lot and strongly depend on the number of active targets (which does not happen if I use the software acceleration).

    Has anyone encountered the same problems?
    Can you recommend something about it?

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