Windowsでの画像ファイルの読書き

細かい事を気にしてはいけない。
Windowscodecs.lib, Shlwapi.lib をリンクすること。


#include <Windows.h>
#include <comdef.h>
#include <wincodec.h>
#include <Shlwapi.h>

_COM_SMARTPTR_TYPEDEF(IWICImagingFactory, __uuidof(IWICImagingFactory));
_COM_SMARTPTR_TYPEDEF(IWICBitmapDecoder, __uuidof(IWICBitmapDecoder));
_COM_SMARTPTR_TYPEDEF(IWICBitmapFrameDecode, __uuidof(IWICBitmapFrameDecode));
_COM_SMARTPTR_TYPEDEF(IWICBitmapSource, __uuidof(IWICBitmapSource));
_COM_SMARTPTR_TYPEDEF(IStream, __uuidof(IStream));
_COM_SMARTPTR_TYPEDEF(IWICBitmapEncoder, __uuidof(IWICBitmapEncoder));
_COM_SMARTPTR_TYPEDEF(IWICBitmapFrameEncode, __uuidof(IWICBitmapFrameEncode));


HRESULT read(void **ppData, UINT *pWidth, UINT *pHeight, LPCWSTR pName)
{
    IWICImagingFactoryPtr pFactory;
    IWICBitmapDecoderPtr pDecoder;
    IWICBitmapFrameDecodePtr pFrame;
    IWICBitmapSourcePtr pBitmap;
    UINT stride;
    UINT size;


    pFactory.CreateInstance(CLSID_WICImagingFactory, NULL, CLSCTX_INPROC_SERVER);
    pFactory->CreateDecoderFromFilename(pName, NULL, GENERIC_READ, WICDecodeMetadataCacheOnDemand, &pDecoder);
    pDecoder->GetFrame(0, &pFrame);
    WICConvertBitmapSource(GUID_WICPixelFormat32bppBGR, pFrame, &pBitmap); //DIB section compatible
    pBitmap->GetSize(pWidth, pHeight);
    stride = 4 * *pWidth;
    size = stride * *pHeight;
    *ppData = new BYTE[size];
    pBitmap->CopyPixels(NULL, stride, size, (BYTE *)*ppData);

    return S_OK;
}

HRESULT writeBmp(LPCWSTR pName, void *pData, UINT width, UINT height)
{
    IWICImagingFactoryPtr pFactory;
    IWICBitmapEncoderPtr pEncoder;
    IStreamPtr pStream;
    IWICBitmapFrameEncodePtr pFrame;
    WICPixelFormatGUID guidFormat;


    pFactory.CreateInstance(CLSID_WICImagingFactory, NULL, CLSCTX_INPROC_SERVER);
    pFactory->CreateEncoder(GUID_ContainerFormatBmp, NULL, &pEncoder);
    SHCreateStreamOnFileEx(pName, STGM_READWRITE| STGM_CREATE, FILE_ATTRIBUTE_NORMAL, TRUE, NULL, &pStream);
    pEncoder->Initialize(pStream, WICBitmapEncoderNoCache);
    pEncoder->CreateNewFrame(&pFrame, NULL);
    pFrame->Initialize(NULL);
    guidFormat = GUID_WICPixelFormat32bppBGR;
    pFrame->SetPixelFormat(&guidFormat);
    pFrame->SetSize(width, height);
    pFrame->WritePixels(height, 4*width, 4*width*height, (BYTE *)pData);
    pFrame->Commit();
    pEncoder->Commit();

    return S_OK;
}