开源项目之在线网页截图工具 IECapt(一)

这个项目是win32程序，就一个目标文件。
class CEventSink :public CComObjectRootEx , public IDispatch 实现了网页接口的事件接收器。
class CMain :public CWindowImpl 窗口主要界面，快照的实现（获得网页接口对象）。

快照实现部分：
[cpp]
//////////////////////////////////////////////////////////////////
// Implementation of CMain::SaveSnapshot
//////////////////////////////////////////////////////////////////
BOOL CMain::SaveSnapshot(void)
{
long bodyHeight, bodyWidth, rootHeight, rootWidth, height, width;


CComPtr pDispatch;


// TODO: "If the document object type is not safe for scripting,
// this method returns successfully but sets ppDisp to NULL. For
// Internet Explorer 7 and later, the return code is S_FALSE..."

//获得对象
HRESULT hr = m_pWebBrowser->get_Document(&pDispatch);


if (FAILED(hr))
return true;

//获得ihtml接口
CComPtr spDocument;
hr = pDispatch->QueryInterface(IID_IHTMLDocument2, (void**)&spDocument);


if (FAILED(hr))
return true;

//获得内容
CComPtr spBody;
hr = spDocument->get_body(&spBody);


// Apparently with MSHTML failing to get the body is not a failure,
// so if there is no HTML body to get, which may be the case with
// SVG images loaded directly, this succeeds but sets spBody to the
// NULL pointer, leading to a crash. I am not sure how to obtain
// the sizing information for SVG documents so this errors out here.
// A work around would be the make HTML host documents or wrapping
// the SVG code in a XHTML document, but that may break scripts.
if (FAILED(hr) || spBody == NULL)
return true;

//查找相关接口
CComPtr spBody2;
hr = spBody->QueryInterface(IID_IHTMLElement2, (void**)&spBody2);


if (FAILED(hr))
return true;


hr = spBody2->get_scrollHeight(&bodyHeight);


if (FAILED(hr))
return true;


hr = spBody2->get_scrollWidth(&bodyWidth);


if (FAILED(hr))
return true;