C++win32GDI+如何将PNG图片转化为d2d资源

在C++ Win32环境中，使用GDI+将PNG图片转换为Direct2D (D2D) 可识别的资源通常涉及以下步骤：

1. **引入必要的库**[^1]:

   #include <windows.h>
   #include <wicapi.h> // 引入Windows Imaging Component (WIC) 库

2. **加载PNG图片**:

   IWICImagingFactory* factory;
   HRESULT hr = CoCreateInstance(__uuidof(WICImagingFactory), NULL, CLSCTX_ALL, __uuidof(IWICImagingFactory), (void**)&factory);
   if (!SUCCEEDED(hr))
      return hr;

   IStream* stream = nullptr;
   hr = ::CreateFileInputStreamFromFile(L"example.png", &stream); // 替换为你的PNG文件路径
   if (!SUCCEEDED(hr))
      return hr;

   IWICStreamSource* source;
   hr = factory->CreateStreamFromStreamSource(stream, &source);

3. **创建WIC Bitmap**:

   IWICBitmapDecoder* decoder;
   hr = factory->CreateDecoderFromStream(source, NULL, WICDecodeMetadataCacheOnLoad, &decoder);
   if (!SUCCEEDED(hr))
      return hr;

   IWICBitmapFrameDecode* frame;
   hr = decoder->GetFrame(0, &frame);
   if (!SUCCEEDED(hr))
      return hr;

   IWICBitmapScaler* scaler;
   hr = factory->CreateBitmapScaler(frame, &scaler);

4. **转换为D2D Bitmap**:

   ID2D1DeviceContext* deviceContext;
   D2DCREATE Options = { D2D1_FACTORY_TYPE_SINGLE_THREADED };
   hr = D2D1CreateFactory(D2D1_FACTORY_TYPE_SINGLE_THREADED, &Options, IID_PPV_ARGS(&deviceContext));
   if (!SUCCEEDED(hr))
      return hr;

   ID2D1Bitmap* d2dBmp;
   hr = scaler->CopyToBitmap(deviceContext, &d2dBmp);

5. **清理资源**:

   delete d2dBmp;
   scaler->Release();
   frame->Release();
   decoder->Release();
   source->Release();
   stream->Release();
   factory->Release();

以上代码展示了基本流程，实际项目中可能还需要处理异常和错误情况。记得替换示例中的文件路径，并根据需求调整缩放比例。