Hi guys,
I want to capture html using win32 api and ATL, not using MFC.
I use a IE control to load a web page, and can get IHTMLElement from
the control. But I can NOT get "IHTMLElementRender" through
"QueryInterface(...)", it returns 0x80004002(E_NOINTERFACE: No such
interface supported.)
My code is as below, it can successfully load the web page, but can't
save it as image.
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#include "stdafx.h"
#include "mshtml.h"
#include <Exdisp.h> //for IWebBrowser2
#include <atlwin.h> //for CAxWindow
#include <atltypes.h> //for CRect
#include <atlstr.h>
#include <atlimage.h>//for CImage
#include <assert.h>
void TestIEControl()
{
CoInitialize(NULL);
CComPtr<IWebBrowser2> pBrowser;
CoCreateInstance(
CLSID_InternetExplorer,
NULL,
CLSCTX_LOCAL_SERVER,
IID_IWebBrowser2,
(void**)&pBrowser
);
CString url(L"www.google.com");
BSTR ole_url = url.AllocSysString();
HRESULT hr = pBrowser->put_Visible(TRUE);
assert(SUCCEED(hr));
VARIANT varEmpty;
VariantInit(&varEmpty);
hr = pBrowser->Navigate(ole_url, &varEmpty, &varEmpty, &varEmpty,
&varEmpty);
assert(SUCCEEDED(hr));
if(!SUCCEEDED(hr))
{
pBrowser->Quit();
}
::SysFreeString(ole_url);
Sleep(2000);
CComPtr<IDispatch> pDisp;
hr = pBrowser->get_Document(&pDisp);
assert(SUCCEEDED(hr));
CComPtr<IHTMLDocument2> pDoc;
hr = pDisp->QueryInterface(IID_IHTMLDocument2, (void**)&pDoc);
assert(SUCCEEDED(hr));
CComPtr<IHTMLElement> pElement;
hr = pDoc->get_body(&pElement);
assert(SUCCEEDED(hr));
int iWidth = 800;
int iHeight = 600;
CImage img;
BOOL bCreated = img.Create(iWidth, -iHeight, 24);
assert(bCreated);
HDC dcImg = img.GetDC();
assert(dcIm);
HDC memDc = ::CreateCompatibleDC(dcImg);
assert(memDc != NULL);
HBITMAP hBitmap = ::CreateCompatibleBitmap(memDc, iWidth,
iHeight);
assert(hBitmap != NULL);
//img.Attach(hBitmap);
::SelectObject(memDc, hBitmap);
CComPtr<IHTMLElementRender> pRender;
hr = pElement->QueryInterface(IID_IHTMLElementRender,
(void**)&pRender);
//Fail here! pRender is NULL.
//TODO IHTMLElementRender Fail
//CComQIPtr<IHTMLElementRender> pRender;
//pRender = pElement;
if(!pRender)
printf("pElement->QueryInterface(IID_IHTMLElementRender...Fail
\n");
printf("%x\n", hr);
assert(pRender != NULL);
hr = pRender->DrawToDC(memDc);
assert(SUCCEEDED(hr));
BOOL rst = ::BitBlt(
dcImg, 0, 0, 800, 600,
memDc, 0, 0,
SRCCOPY);
assert(rst);
rst = ::GdiFlush();
assert(rst);
hr = img.Save(L"rst.bmp");
assert(SUCCEEDED(hr));
/*
::SelectObject(memDc, NULL);
rst = :
eleteObject(hBitmap);
assert(rst);
*/
img.ReleaseDC();
((IWebBrowser2*)pBrowser)->Release();
CoUninitialize();
}
int _tmain(int argc, _TCHAR* argv[])
{
TestIEControl();
return 0;
}
Thank you for any possible suggestion and feedback, 
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