RichEdit 不显示图片

Question

我在写字板中创建了一个简单的 RTF 文档，截图如下：

看来，除了图片，RTF 的所有格式都可以正常工作，图片替换为空字符串。这是 RichEdit 的截图：

我尝试了 .bmp 和 .png。我还尝试了不同版本的 RichEdit 库： Riched20.dll 和 Msftedit.dll。在我的 .rtf 文件中有一个字符串 {\*\generator Riched20 10.0.19041}，我想它是一个库和 SDK 版本，在 Visual Studio 中我使用相同的。

我用来加载 RTF 的代码很流行，取自互联网：

    static DWORD CALLBACK FileStreamCallback(DWORD dwCookie, LPBYTE pbBuff,    LONG cb, LONG* pcb)
    {
        std::ifstream* pFile = (std::ifstream*)dwCookie;
        pFile->read((char*)pbBuff, cb);
        return 0;
    }

    // ...
    std::fstream file{ filePath };
    EDITSTREAM   editStream = { 0 };
    editStream.dwCookie = (DWORD)&file;
    editStream.pfnCallback = FileStreamCallback;
    SendMessage(hwndEdit, EM_STREAMIN, SF_RTF, (LPARAM)&editStream);

为了简洁起见，这里是带有剪切图像数据的 RTF：

{\rtf1\ansi\ansicpg1251\deff0\nouicompat\deflang1049\deflangfe1049{\fonttbl{\f0\fswiss\fprq2\fcharset204 Calibri;}{\f1\fswiss\fprq2\fcharset0 Calibri;}}
{\colortbl ;\red0\green0\blue255;}
{\*\generator Riched20 10.0.19041}{\*\mmathPr\mdispDef1\mwrapIndent1440 }\viewkind4\uc1 
\pard\nowidctlpar\sa200\sl240\slmult1\f0\fs22{\pict{\*\picprop}\wmetafile8\picw1323\pich1323\picwgoal750\pichgoal750 
010009000003260300000000fd02000000000400000003010800050000000b0200000000050000
// intermediate data
0000002701ffff030000000000
}\par
\strike Hello\strike0 .\par

\pard 
{\pntext\f0 a.\tab}{\*\pn\pnlvlbody\pnf0\pnindent0\pnstart1\pnlcltr{\pntxta.}}
\nowidctlpar\fi-360\li720\sa200\sl240\slmult1\f1\lang1033 34\f0\lang1049\par
{\pntext\f0 b.\tab}\f1\lang1033 28\f0\lang1049\par

\pard\nowidctlpar\sa200\sl240\slmult1 {\f1\lang1033{\field{\*\fldinst{HYPERLINK www.google.com }}{\fldrslt{www.google.com\ul0\cf0}}}}\f0\fs22\par
}

我也发现了一些指控，即 RichEdit 实际上无法使用上述方法处理图像。我不知道如何对待他们。

Answer 1

要在 Richedit 中插入位图，请参阅 example (InsertObject(HWND hRichEdit, LPCTSTR pszFileName))

否则，写字板 rtf 文件中的位图将保存为十进制格式的数字。要阅读它，需要IRichEditOleCallback 接口。

创建一个名为"cole_callback.h" 的新文件，如下所示：

#include <richole.h>

interface cole_callback : public IRichEditOleCallback
{
public:
    IStorage* pstorage;
    DWORD m_ref;
    int grfmode;
    cole_callback() : grfmode(STGM_TRANSACTED | STGM_READWRITE | STGM_SHARE_EXCLUSIVE | STGM_CREATE)
    {
        pstorage = nullptr;
        m_ref = 0;
        (void)StgCreateDocfile(NULL, grfmode, 0, &pstorage);
    }

    HRESULT STDMETHODCALLTYPE GetNewStorage(LPSTORAGE* lplpstg)
    {
        wchar_t name[256] = { 0 };
        return pstorage->CreateStorage(name, grfmode, 0, 0, lplpstg);
    }

    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID iid, void** lplpObj)
    {
        *lplpObj = NULL;
        if (iid == IID_IUnknown || iid == IID_IRichEditOleCallback)
        {
            *lplpObj = this;
            AddRef();
            return NOERROR;
        }
        return E_NOINTERFACE;
    }

    ULONG STDMETHODCALLTYPE AddRef()
    {
        return ++m_ref;
    }

    ULONG STDMETHODCALLTYPE Release()
    {
        if (--m_ref == 0) { delete this; return 0; }
        return m_ref;
    }

    STDMETHOD(GetInPlaceContext) (LPOLEINPLACEFRAME FAR*, LPOLEINPLACEUIWINDOW FAR*, LPOLEINPLACEFRAMEINFO) { return S_OK; }
    STDMETHOD(ShowContainerUI) (BOOL) { return S_OK; }
    STDMETHOD(QueryInsertObject) (LPCLSID, LPSTORAGE, LONG) { return S_OK; }
    STDMETHOD(DeleteObject) (LPOLEOBJECT) { return S_OK; }
    STDMETHOD(QueryAcceptData) (LPDATAOBJECT, CLIPFORMAT FAR*, DWORD, BOOL, HGLOBAL) { return S_OK; }
    STDMETHOD(ContextSensitiveHelp) (BOOL) { return S_OK; }
    STDMETHOD(GetClipboardData) (CHARRANGE FAR*, DWORD, LPDATAOBJECT FAR*) { return S_OK; }
    STDMETHOD(GetDragDropEffect) (BOOL, DWORD, LPDWORD) { return S_OK; }
    STDMETHOD(GetContextMenu) (WORD, LPOLEOBJECT, CHARRANGE FAR*, HMENU FAR*) { return S_OK; }
};

下一步，创建cole_callback 的新实例，并使用EM_SETOLECALLBACK 消息发送它。接下来使用EM_STREAMIN读取rtf文件

#include <"cole_callback.h">
...
LoadLibrary(L"Riched20.dll");
...
cole_callback* ole_callback = new cole_callback;
...
richedit = CreateWindowEx(0, RICHEDIT_CLASS, ...

SendMessage(richedit, EM_SETOLECALLBACK, 0, (LPARAM)ole_callback);

auto callback = [](DWORD ptr, LPBYTE buf, LONG count, LONG* red)
{
    auto fp = (std::ifstream*)ptr;
    fp->read((char*)buf, count);
    *red = (LONG)fp->gcount();
    return DWORD(0);
};
std::ifstream fin(L"c:/test/document.rtf", std::ios::binary);
EDITSTREAM es{ (DWORD_PTR)&fin, 0, callback };
SendMessage(richedit, EM_STREAMIN, WPARAM(SF_RTF), (LPARAM)&es);