CODEWITHSUNDEEP
uwpc++-cliwin2d
James Autry
James Autry

Reputation: 81

Memory Leak using Win2D CanvasDrawingSession

I have created an image effect which overlays a time on an existing image. The problem I have seems to be a persistent memory leak every time I use DrawImage or DrawText on a Win2D CanvasDrawingSession. This becomes very significant over time. I must be missing something in freeing resources, but I do not see it. If I comment out the DrawImage and DrawText lines of code, the memory leak ceases.

        virtual void ProcessFrame(ProcessVideoFrameContext^ context)
    {
        time_t curtime = time(0);
        char buffer[16];
        struct tm info;
        localtime_s(&info, &curtime);
        strftime(buffer, sizeof(buffer), "%H:%M:%S", &info);
        std::string stime = std::string(buffer);
        std::wstring w_str = std::wstring(stime.begin(), stime.end());
        String^ sTime = ref new String(w_str.c_str());
        CanvasDevice^ device = ref new CanvasDevice();
        auto newBitmap = SoftwareBitmap::Convert(context->InputFrame->SoftwareBitmap, BitmapPixelFormat::Bgra8);

        auto inputBitmap = CanvasBitmap::CreateFromSoftwareBitmap(device, newBitmap);
        auto frameSize = inputBitmap->SizeInPixels.Width * inputBitmap->SizeInPixels.Height * 4;
        auto frameBuffer = ref new Windows::Storage::Streams::Buffer((unsigned int)frameSize);

        auto renderTarget = ref new CanvasRenderTarget(device, (float)inputBitmap->SizeInPixels.Width, (float)inputBitmap->SizeInPixels.Height, (float)inputBitmap->Dpi);

        auto ds = renderTarget->CreateDrawingSession();
//      ds->DrawImage(inputBitmap);

        auto format = ref new CanvasTextFormat();
        format->FontFamily = _fontFamily;
        format->FontSize = (float)_fontSize;
//      ds->DrawText(sTime, (float)_offsetX, (float)_offsetY, _fontColor, format);
        delete ds;

        renderTarget->GetPixelBytes(frameBuffer);

        SoftwareBitmap^ nxtBitmap = ref new SoftwareBitmap(BitmapPixelFormat::Bgra8, newBitmap->PixelWidth, newBitmap->PixelHeight);
        nxtBitmap->CopyFromBuffer(frameBuffer);
        SoftwareBitmap^ anBitmap = SoftwareBitmap::Convert(nxtBitmap, BitmapPixelFormat::Yuy2);
        anBitmap->CopyToBuffer(frameBuffer);

        // Copy the modified frame data to the output frame.
        context->OutputFrame->SoftwareBitmap->CopyFromBuffer(frameBuffer);

        delete format;
        delete nxtBitmap;
        delete anBitmap;

        delete inputBitmap;
        delete frameBuffer;
        delete renderTarget;

        delete sTime;
        delete device;
        delete newBitmap;
    }

Upvotes: 0

Views: 235

Answers (1)

James Autry
James Autry

Reputation: 81

I discovered that it was due to creating a new CanvasDevice on each frame. Once I moved it to a global device, the leak situation resolved itself.

Upvotes: 4

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