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Direct2DでイメージファイルであるPNGを表示する方法。

ID2D1RenderTarget* cxt = ...
CComPtr bmp;

D2DResource::LoadImage( cxt, L"e:\test\images\abc.png", &bmp );

// auto image_size = bmp->GetPixelSize();　イメージの大きさ
//リソースから読み込む場合

//CComPtr bmp;

//D2DResource::LoadImage( cxt, L"png", IDB_PNG1, &bmp );
D2D1_RECT_U rc = ...
cxt->DrawBitmap( bmp, rc );


/////////////////////////////////////////////////////////////////////////////////////////////////////

class D2DResource

{

	public :

		static bool LoadImage ( ID2D1RenderTarget* target, LPCWSTR filenm, ID2D1Bitmap** bmp );

		static bool LoadImage ( ID2D1RenderTarget* target, LPCWSTR resource_section, int resource_id, ID2D1Bitmap** bmp );

		static bool LoadImage2( ID2D1RenderTarget* target, IWICImagingFactory* pWICFactory, IWICStream* pStream, ID2D1Bitmap** bmp );

};


bool D2DResource::LoadImage( ID2D1RenderTarget* target, LPCWSTR filenm, ID2D1Bitmap** bmp )

{

	HRESULT hr;

	CComPtr pStream;

	CComPtr pWICFactory;	
	hr = CoCreateInstance( CLSID_WICImagingFactory, NULL, CLSCTX_ALL, __uuidof(IWICImagingFactory), (void**)&pWICFactory );

	if ( hr != S_OK ) return false;

	hr = pWICFactory->CreateStream( &pStream );

	if ( hr != S_OK ) return false;

	hr = pStream->InitializeFromFilename( filenm, GENERIC_READ); // bmp,gif,jpg,png OK

	if ( hr != S_OK ) return false;

	

	return LoadImage2( target,pWICFactory, pStream, bmp );

}
bool D2DResource::LoadImage( ID2D1RenderTarget* target, LPCWSTR resource_section, int resource_id, ID2D1Bitmap** bmp )

{

	HRESULT hr;

	CComPtr pWICFactory;	

	CComPtr pStream;
	hr= CoCreateInstance( CLSID_WICImagingFactory, NULL, CLSCTX_ALL, __uuidof(IWICImagingFactory), (void**)&pWICFactory );

	if ( hr != S_OK ) return false;
	// load png from .rc

	HMODULE hmodule = ::GetModuleHandle(NULL);

	HRSRC hsrc = FindResource( hmodule,  MAKEINTRESOURCE(resource_id), resource_section ); // resource_section:png

	if ( hsrc == NULL ) return false;
	DWORD len = SizeofResource(hmodule,hsrc);

	HGLOBAL hg = LoadResource( hmodule, hsrc );

	byte* d = (byte*)LockResource( hg );
	hr = pWICFactory->CreateStream( &pStream );

	if ( hr != S_OK ) return false;	

	hr = pStream->InitializeFromMemory( d, len ); // bmp,gif,jpg,png OK

	if ( hr != S_OK ) return false;
	return LoadImage2( target,pWICFactory, pStream, bmp );

}


bool D2DResource::LoadImage2( ID2D1RenderTarget* target,IWICImagingFactory* pWICFactory,IWICStream* pStream, ID2D1Bitmap** bmp )

{

	_ASSERT( pWICFactory );
	HRESULT hr;
	CComPtr pDecoder;

	CComPtr pSource;	

	CComPtr pConverter;
	hr = pWICFactory->CreateDecoderFromStream( pStream, 0, WICDecodeMetadataCacheOnLoad, &pDecoder ); // jpeg,png:OK, bmp:88982f50のエラーになる, iconもエラー

	if ( hr != S_OK ) return false;

	hr = pDecoder->GetFrame(0, &pSource);

	if ( hr != S_OK ) return false;
	// Convert the image format to 32bppPBGRA

	// (DXGI_FORMAT_B8G8R8A8_UNORM + D2D1_ALPHA_MODE_PREMULTIPLIED).

	hr = pWICFactory->CreateFormatConverter(&pConverter);

	if ( hr != S_OK ) return false;

	hr = pConverter->Initialize( pSource, GUID_WICPixelFormat32bppPBGRA,WICBitmapDitherTypeNone,NULL,0.f,WICBitmapPaletteTypeMedianCut);

	if ( hr != S_OK ) return false;

	hr = target->CreateBitmapFromWicBitmap(pConverter,NULL,bmp );
	return ( hr == S_OK );

}