外文名
cimage
头文件
atlimage.h
主要作用
图片文件的打开，显示与保存
简介
ATL和MFC共用的一个类
行为
保存图片
保存图片只有一个函数，就是Save函数，该函数有两个参数，一个是文件的完整路径和文件名，一个是文件的扩展名。但是如果只有保存和显示图片功能，CImage的Save函数发挥不了太大的作用，不过是一个转存文件的工具。CImage的强大之处在于可以对图片进行修改，再进行保存。
修改图片的函数有这么3个函数可以修改图片，都是像素级的 *** 作。这三个函数分别为SetPixel，SetPixelRGB，SetPixelIndexed。可以通过双重循环对屏幕进行逐点扫描，并把像素颜色值保存到CImage对象中达到截屏的目的。
我们可以用一段很简单的代码来实现将DC（设备上下文）里绘制的图形存入图片文件中。基本的思想是先初始化一个销芹派CImage对象，再为它设定大小和位数，也就是图片大小和图片的色彩总数，再用设备上下文绘图。绘制完图形后再建立另外一个设备上下文对象，称为目的DC，将之前绘图的DC称为源DC，目的DC必须与CImage对象关联起来，然后利用BitBlt函数和其他函数将绘图DC的内容拷贝到目的DC中，最后将CImage对象保存到文件中，以下是代码实现（VS2010支持中文变量名）：
CRect rect
this->GetClientRect(rect)
CImage image
image.Create(rect.Width(),rect.Height(),24)
CDC* DCpoint=this->GetDC()
DCpoint->Ellipse(20,20,200,200)
CDC dstDC
dstDC.CreateCompatibleDC(DCpoint)
dstDC.SelectObject(image)
dstDC.BitBlt(0,0,rect.Width(),rect.Height(),DCpoint,0,0,SRCCOPY)
image.Save(L"D:\\用户目录\\Pictures\\写图片文件.jpg")
显示图片
首先看下面这段代码
CImage image
image.Load(L"D:\\用户目录\\Pictures\\example.jpg")
image.Draw(GetDC()->m_hDC,CRect(0,0,320,240))
CImage类支持以Load方法读取本地磁盘上的文件，并用Draw方法来显示图片。CIamge类的成员函数中还有很多可以实现显示图片。例如BitBlt办法。如以下代码：
image.BitBlt(GetDC()->m_hDC,0,0,320,240,0,0,SRCCOPY)
Bitblt方法同CDC类的Bitblt函数一样，是一比一地复制图像并显示在屏幕上，支持对源图像取反，也就是反色显示。这样功能通过BitBlt的最后一个参数来实现，比如参数为NOTSRCCOPY就是反色显示。
MaskBlt可以将图片与目的图片进行特殊的光栅 *** 作并进行掩码处理。
PlgBlt函数可以将图首派片拉伸成平行四边形进行显示。
StretchBlt函数可以将图片进行拉伸显示。
告诉你一个最简单的方法,你一定可以的神槐,弄好了记得给我加分.1.在你的对话游察友框添一个按钮和一个图片控件(Picture Control).
2.添加一个类,我这里上传不了,只能将.h和.cpp复制过来,你再将拷贝到txt里,改一下扩展名就可以了。
这是Picture.h
#if !defined(AFX_PICTURE_H__COPYFREE_BY_YOVAV_GAD__SOURCES_AT_SUPERMAIN_DOT_COM__INCLUDED_)
#define AFX_PICTURE_H__COPYFREE_BY_YOVAV_GAD__SOURCES_AT_SUPERMAIN_DOT_COM__INCLUDED_
#if _MSC_VER >1000
#pragma once
#endif // _MSC_VER >1000
class CPicture
{
public:
void FreePictureData()
BOOL Load(CString sFilePathName)
BOOL Load(UINT ResourceName, LPCSTR ResourceType)
BOOL LoadPictureData(BYTE* pBuffer, int nSize)
BOOL SaveAsBitmap(CString sFilePathName)
BOOL Show(CDC* pDC, CPoint LeftTop, CPoint WidthHeight, int MagnifyX, int MagnifyY)
BOOL Show(CDC* pDC, CRect DrawRect)
BOOL ShowBitmapResource(CDC* pDC, const int BMPResource, CPoint LeftTop)
BOOL UpdateSizeOnDC(CDC* pDC)
CPicture()
virtual ~CPicture()
IPicture* m_IPicture// Same As LPPICTURE (typedef IPicture __RPC_FAR *LPPICTURE)
LONG m_Height// Height (In Pixels Ignor What Current Device Context Uses)
LONG m_Weight// Size Of The Image Object In Bytes (File OR Resource)
LONG m_Width // Width (In Pixels Ignor What Current Device Context Uses)
}
#endif
这是Picture.cpp
#include "stdafx.h"
#include "Picture.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__
#endif
#define HIMETRIC_INCH 2540
#define ERROR_TITLE "CPicture Error" // Error Title (Related To This Class)...
//-----------------------------------------------------------------------------
// Does: Constructor - Create a New CPicture Object To Hold Picture Data
// ~~~~
//
//-----------------------------------------------------------------------------
CPicture::CPicture()
/没羡/=============================================================================
{
m_IPicture = NULL
m_Height = 0
m_Weight = 0
m_Width = 0
}
//-----------------------------------------------------------------------------
// Does: Destructor - Free Data And Information From The CPicture Object
// ~~~~
//
//-----------------------------------------------------------------------------
CPicture::~CPicture()
//=============================================================================
{
if(m_IPicture != NULL) FreePictureData()// Important - Avoid Leaks...
}
//-----------------------------------------------------------------------------
// Does: Free The Allocated Memory That Holdes The IPicture Interface Data
// ~~~~And Clear Picture Information
//
// Note: This Might Also Be Useful If U Only Need To Show The Picture Once
// ~~~~~ Or If U Copy The Picture To The Device Context, So It Can Still
// Remain On Screen - But IPicture Data Is Not Needed No More
//
//-----------------------------------------------------------------------------
void CPicture::FreePictureData()
//=============================================================================
{
if(m_IPicture != NULL)
{
m_IPicture->Release()
m_IPicture = NULL
m_Height = 0
m_Weight = 0
m_Width = 0
}
}
//-----------------------------------------------------------------------------
// Does: Open a Resource And Load It Into IPicture (Interface)
// ~~~~(.BMP .DIB .EMF .GIF .ICO .JPG .WMF)
//
// Note: When Adding a Bitmap Resource It Would Automatically Show On "Bitmap"
// ~~~~This NOT Good Coz We Need To Load It From a Custom Resource "BMP"
// To Add a Custom Rresource: Import Resource ->Open As ->Custom
// (Both .BMP And .DIB Should Be Found Under "BMP")
//
// InPut: ResourceName - As a UINT Defined (Example: IDR_PICTURE_RESOURCE)
// ~~~~~ ResourceType - Type Name (Example: "JPG")
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::Load(UINT ResourceName, LPCSTR ResourceType)
//=============================================================================
{
BOOL bResult = FALSE
HGLOBAL hGlobal = NULL
HRSRC hSource = NULL
LPVOID lpVoid = NULL
int nSize = 0
if(m_IPicture != NULL) FreePictureData()// Important - Avoid Leaks...
hSource = FindResource(AfxGetResourceHandle(), MAKEINTRESOURCE(ResourceName), ResourceType)
if(hSource == NULL)
{
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, "FindResource() Failed\t", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
return(FALSE)
}
hGlobal = LoadResource(AfxGetResourceHandle(), hSource)
if(hGlobal == NULL)
{
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, "LoadResource() Failed\t", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
return(FALSE)
}
lpVoid = LockResource(hGlobal)
if(lpVoid == NULL)
{
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, "LockResource() Failed\t", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
return(FALSE)
}
nSize = (UINT)SizeofResource(AfxGetResourceHandle(), hSource)
if(LoadPictureData((BYTE*)hGlobal, nSize)) bResult = TRUE
UnlockResource(hGlobal)// 16Bit Windows Needs This
FreeResource(hGlobal)// 16Bit Windows Needs This (32Bit - Automatic Release)
m_Weight = nSize// Update Picture Size Info...
if(m_IPicture != NULL) // Do Not Try To Read From Memory That Is Not Exist...
{
m_IPicture->get_Height(&m_Height)
m_IPicture->get_Width(&m_Width)
// Calculate Its Size On a "Standard" (96 DPI) Device Context
m_Height = MulDiv(m_Height, 96, HIMETRIC_INCH)
m_Width = MulDiv(m_Width, 96, HIMETRIC_INCH)
}
else // Picture Data Is Not a Known Picture Type
{
m_Height = 0
m_Width = 0
bResult = FALSE
}
return(bResult)
}
//-----------------------------------------------------------------------------
// Does: Open a File And Load It Into IPicture (Interface)
// ~~~~(.BMP .DIB .EMF .GIF .ICO .JPG .WMF)
//
// InPut: sFilePathName - Path And FileName Target To Save
// ~~~~~
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::Load(CString sFilePathName)
//=============================================================================
{
BOOL bResult = FALSE
CFile PictureFile
CFileException e
int nSize = 0
if(m_IPicture != NULL) FreePictureData()// Important - Avoid Leaks...
if(PictureFile.Open(sFilePathName, CFile::modeRead | CFile::typeBinary, &e))
{
nSize = PictureFile.GetLength()
BYTE* pBuffer = new BYTE[nSize]
if (PictureFile.Read(pBuffer, nSize) >0 ) //从文件读到pBuffer
{ if(LoadPictureData(pBuffer, nSize)) bResult = TRUE}//接作调用函数读pBuffer
PictureFile.Close()
delete [] pBuffer
}
else // Open Failed...
{
TCHAR szCause[255]
e.GetErrorMessage(szCause, 255, NULL)
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, szCause, ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
bResult = FALSE
}
m_Weight = nSize// Update Picture Size Info...
if(m_IPicture != NULL) // Do Not Try To Read From Memory That Is Not Exist...
{
m_IPicture->get_Height(&m_Height)
m_IPicture->get_Width(&m_Width)
// Calculate Its Size On a "Standard" (96 DPI) Device Context
m_Height = MulDiv(m_Height, 96, HIMETRIC_INCH)
m_Width = MulDiv(m_Width, 96, HIMETRIC_INCH)
}
else // Picture Data Is Not a Known Picture Type
{
m_Height = 0
m_Width = 0
bResult = FALSE
}
return(bResult)
}
//-----------------------------------------------------------------------------
// Does: Read The Picture Data From a Source (File / Resource)
// ~~~~And Load It Into The Current IPicture Object In Use
//
// InPut: Buffer Of Data Source (File / Resource) And Its Size
// ~~~~~
//
// OutPut: Feed The IPicture Object With The Picture Data
// ~~~~~~ (Use Draw Functions To Show It On a Device Context)
// TRUE If Succeeded...
//-----------------------------------------------------------------------------
BOOL CPicture::LoadPictureData(BYTE *pBuffer, int nSize)
//=============================================================================
{
BOOL bResult = FALSE
HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, nSize)
if(hGlobal == NULL)
{
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, "Can not allocate enough memory\t", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
return(FALSE)
}
void* pData = GlobalLock(hGlobal)
memcpy(pData, pBuffer, nSize)
GlobalUnlock(hGlobal)
IStream* pStream = NULL
if(CreateStreamOnHGlobal(hGlobal, TRUE, &pStream) == S_OK)
{
HRESULT hr
if((hr = OleLoadPicture(pStream, nSize, FALSE, IID_IPicture, (LPVOID *)&m_IPicture)) == E_NOINTERFACE)
{
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, "IPicture interface is not supported\t", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
return(FALSE)
}
else // S_OK
{
pStream->Release()
pStream = NULL
bResult = TRUE
}
}
FreeResource(hGlobal)// 16Bit Windows Needs This (32Bit - Automatic Release)
return(bResult)
}
//-----------------------------------------------------------------------------
// Does: Draw The Loaded Picture Direct To The Client DC
// ~~~~
//
// Note: Bigger OR Smaller Dimentions Than The Original Picture Size
// ~~~~Will Draw The Picture Streached To Its New Given NEW Dimentions...
//
// InPut: pDC - Given DC To Draw On
// ~~~~~ DrawRect - Dimentions Of The Picture To Draw (As a Rectangle)
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::Show(CDC *pDC, CRect DrawRect)
//=============================================================================
{
if (pDC == NULL || m_IPicture == NULL) return FALSE
long Width = 0
long Height = 0
m_IPicture->get_Width(&Width)
m_IPicture->get_Height(&Height)
HRESULT hrP = NULL
hrP = m_IPicture->Render(pDC->m_hDC,
DrawRect.left, // Left
DrawRect.top, // Top
DrawRect.right - DrawRect.left, // Right
DrawRect.bottom - DrawRect.top, // Bottom
0,
Height,
Width,
-Height,
&DrawRect)
if (SUCCEEDED(hrP)) return(TRUE)
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, "Can not allocate enough memory\t", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
return(FALSE)
}
//-----------------------------------------------------------------------------
// Does: Draw The Loaded Picture Direct To The Client DC
// ~~~~
//
// Note: Bigger OR Smaller Dimentions Than The Original Picture Size
// ~~~~Will Draw The Picture Streached To Its New Given Dimentions...
//
// InPut: pDC - Given DC To Draw On
// ~~~~~ LeftTop - Opening Point To Start Drawing (Left,Top)
// WidthHeight - Dimentions Of The Picture To Draw (Width,Height)
// MagnifyX - Magnify Pixel Width, 0 = Default (No Magnify)
// MagnifyY - Magnify Pixel Height, 0 = Default (No Magnify)
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::Show(CDC *pDC, CPoint LeftTop, CPoint WidthHeight, int MagnifyX, int MagnifyY)
//=============================================================================
{
if (pDC == NULL || m_IPicture == NULL) return FALSE
long Width = 0
long Height = 0
m_IPicture->get_Width(&Width)
m_IPicture->get_Height(&Height)
if(MagnifyX == NULL) MagnifyX = 0
if(MagnifyY == NULL) MagnifyY = 0
MagnifyX = int(MulDiv(Width, pDC->GetDeviceCaps(LOGPIXELSX), HIMETRIC_INCH) * MagnifyX)
MagnifyY = int(MulDiv(Height,pDC->GetDeviceCaps(LOGPIXELSY), HIMETRIC_INCH) * MagnifyY)
CRect DrawRect(LeftTop.x, LeftTop.y, MagnifyX, MagnifyY)
HRESULT hrP = NULL
hrP = m_IPicture->Render(pDC->m_hDC,
LeftTop.x, // Left
LeftTop.y, // Top
WidthHeight.x +MagnifyX, // Width
WidthHeight.y +MagnifyY, // Height
0,
Height,
Width,
-Height,
&DrawRect)
if(SUCCEEDED(hrP)) return(TRUE)
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, "Can not allocate enough memory\t", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
return(FALSE)
}
//-----------------------------------------------------------------------------
// Does: Saves The Picture That Is Stored In The IPicture Object As a Bitmap
// ~~~~(Converts From Any Known Picture Type To a Bitmap / Icon File)
//
// InPut: sFilePathName - Path And FileName Target To Save
// ~~~~~
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::SaveAsBitmap(CString sFilePathName)
//=============================================================================
{
BOOL bResult = FALSE
ILockBytes *Buffer = 0
IStorage *pStorage = 0
IStream*FileStream = 0
BYTE*BufferBytes
STATSTG BytesStatistics
DWORD OutData
long OutStream
CFile BitmapFileCFileException e
double SkipFloat = 0
DWORD ByteSkip = 0
_ULARGE_INTEGER RealData
CreateILockBytesOnHGlobal(NULL, TRUE, &Buffer)// Create ILockBytes Buffer
HRESULT hr = ::StgCreateDocfileOnILockBytes(Buffer,
STGM_SHARE_EXCLUSIVE | STGM_CREATE | STGM_READWRITE, 0, &pStorage)
hr = pStorage->CreateStream(L"PICTURE",
STGM_SHARE_EXCLUSIVE | STGM_CREATE | STGM_READWRITE, 0, 0, &FileStream)
m_IPicture->SaveAsFile(FileStream, TRUE, &OutStream)// Copy Data Stream
FileStream->Release()
pStorage->Release()
Buffer->Flush()
// Get Statistics For Final Size Of Byte Array
Buffer->Stat(&BytesStatistics, STATFLAG_NONAME)
// Cut UnNeeded Data Coming From SaveAsFile() (Leave Only "Pure" Picture Data)
SkipFloat = (double(OutStream) / 512)// Must Be In a 512 Blocks...
if(SkipFloat >DWORD(SkipFloat)) ByteSkip = (DWORD)SkipFloat + 1
else ByteSkip = (DWORD)SkipFloat
ByteSkip = ByteSkip * 512// Must Be In a 512 Blocks...
// Find Difference Between The Two Values
ByteSkip = (DWORD)(BytesStatistics.cbSize.QuadPart - ByteSkip)
// Allocate Only The "Pure" Picture Data
RealData.LowPart = 0
RealData.HighPart = 0
RealData.QuadPart = ByteSkip
BufferBytes = (BYTE*)malloc(OutStream)
if(BufferBytes == NULL)
{
Buffer->Release()
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, "Can not allocate enough memory\t", ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
}
Buffer->ReadAt(RealData, BufferBytes, OutStream, &OutData)
if(BitmapFile.Open(sFilePathName, CFile::typeBinary | CFile::modeCreate | CFile::modeWrite, &e))
{
BitmapFile.Write(BufferBytes, OutData)
BitmapFile.Close()
bResult = TRUE
}
else // Write File Failed...
{
TCHAR szCause[255]
e.GetErrorMessage(szCause, 255, NULL)
HWND hWnd = AfxGetApp()->GetMainWnd()->m_hWnd
MessageBoxEx(hWnd, szCause, ERROR_TITLE, MB_OK | MB_ICONSTOP, LANG_ENGLISH)
bResult = FALSE
}
Buffer->Release()
free(BufferBytes)
return(bResult)
}
//-----------------------------------------------------------------------------
// Does: Draw a Bitmap Resource To The Client DC (Using Bitblt())
// ~~~~It Will Use The Bitmap Resource Original Size (Width And Height)
// (.BMP .DIB)
//
// Note: This Function Is Just Another Simple Way Of Displaying a Bitmap Resource,
// ~~~~It Is Not Connected With The IPicture Interface And Can Be Used
// As a StandAlone On Any Device Context (Directly)
//
// InPut: BMPResource - Resource Name As Defined In The Resources
// ~~~~~ pDC - Given DC To Draw On
// LeftTop - Opening Point To Start Drawing (Left,Top)
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::ShowBitmapResource(CDC *pDC, const int BMPResource, CPoint LeftTop)
//=============================================================================
{
if (pDC == NULL) return(FALSE)
CBitmap BMP
if(BMP.LoadBitmap(BMPResource))
{
// Get Bitmap Details
BITMAP BMPInfo
BMP.GetBitmap(&BMPInfo)
// Create An In-Memory DC Compatible With The Display DC We R Gonna Paint On
CDC DCMemory
DCMemory.CreateCompatibleDC(pDC)
// Select The Bitmap Into The In-Memory DC
CBitmap* pOldBitmap = DCMemory.SelectObject(&BMP)
// Copy Bits From The In-Memory DC Into The On-Screen DC
pDC->BitBlt(LeftTop.x, LeftTop.y, BMPInfo.bmWidth, BMPInfo.bmHeight, &DCMemory, 0, 0, SRCCOPY)
DCMemory.SelectObject(pOldBitmap)// (As Shown In MSDN Example...)
}
else
{
TRACE0("ERROR: Can Not Find The Bitmap Resource\n")
return(FALSE)
}
return(TRUE)
}
//-----------------------------------------------------------------------------
// Does: Get The Original Picture Pixel Size (Ignor What Current DC Is Using)
// ~~~~Pointer To a Device Context Is Needed For Pixel Calculation,
//
// Also Updates The Class's Height And Width Properties,
// (Coz Till Now We Had No Device Context To Work With...96 DPI Assumed)
//
// InPut: The Client DC (Needed To Check The Size Of The Pixels)
// ~~~~~
//
// OutPut: TRUE If Succeeded...
// ~~~~~~
//-----------------------------------------------------------------------------
BOOL CPicture::UpdateSizeOnDC(CDC *pDC)
//=============================================================================
{
if(pDC == NULL || m_IPicture == NULL) { m_Height = 0m_Width = 0return(FALSE)}
m_IPicture->get_Height(&m_Height)
m_IPicture->get_Width(&m_Width)
// Get Current DPI - Dot Per Inch
int CurrentDPI_X = pDC->GetDeviceCaps(LOGPIXELSX)
int CurrentDPI_Y = pDC->GetDeviceCaps(LOGPIXELSY)
// Use a "Standard" Print (When Printing)
if(pDC->IsPrinting())
{
CurrentDPI_X = 96
CurrentDPI_Y = 96
}
m_Height = MulDiv(m_Height, CurrentDPI_Y, HIMETRIC_INCH)
m_Width = MulDiv(m_Width, CurrentDPI_X, HIMETRIC_INCH)
return(TRUE)
}
3.在对话框头文件定义:
先包含头文件#include "Picture.h"
再定义
CPicture m_Pic
4.给按钮的函数里写上:(注意,这个IDC_SHOWPIC)是你那个显示控件的ID号.
CRect rect
GetDlgItem(IDC_SHOWPIC)->GetWindowRect(&rect)
ScreenToClient(&rect)
CFile f
CString FilePathName
CFileException e
CFileDialog dlg(TRUE,NULL,NULL,0,_T("All Files (*.*)|*.*|BMP (*.bmp)|*.bmp|DIB (*.dib)|*.dib|EMF (*.emf)|*.emf|GIF (*.gif)|*.gif|ICO (*.ico)|*.ico|JPG (*.jpg)|*.jpg|WMF (*.wmf)|*.wmf||"),NULL)
if(dlg.DoModal()==IDOK)
{
FilePathName=dlg.GetPathName()
if(m_Pic.m_IPicture != NULL) m_Pic.FreePictureData()
m_Pic.Load(FilePathName)
CClientDC dc(this)
m_Pic.UpdateSizeOnDC(&dc)
m_Pic.Show(&dc, &rect)
}
32,32 是拷贝dc到pDC的左上角32,32的位置160,160 是拷贝dc的宽度和高度 (以像素为单位)
0,0 是从dc的左上角0.0的位置开始拷贝
CDC::BitBlt
BOOL BitBlt( int x, int y, int nWidth, int nHeight, CDC*
pSrcDC, int xSrc, int ySrc, DWORD dwRop
)
返回值：函数成功，返回非零值，否则为0。
参数：
x
指定目标矩形左上角的逻辑x坐标。
y
指定目标矩形左上角的逻辑y坐标。
nWidth
指定目标矩形和源位图的宽度（逻辑单位）。
nHeight
指定目标矩形和源位图的高度（逻辑单位）。
pSrcDC
指向CDC对象的指针，标识待拷贝位图的设备上下文。如果dwRop指定不包括源的光栅 *** 作，则它必须为NULL。
xSrc
指定源位图左上角的逻辑X坐标。
ySrc
指定源位图左上角的逻辑Y坐标。
dwRop
指定要执行的光栅 *** 作。光栅 *** 作代码定义GDC如何合并输出 *** 作中的颜色，包括当前画刷、可能的源位图和目标位图。下面对dwRop列出光栅 *** 滑源作代码及其描述：BLACKNESS
所有输出变黑。
DSTINVERT
反转目标位图。
MERGECOPY
使用布尔AND *** 作符合并特征与源位图。
MERGEPAINT
使用布尔OR *** 作符合并特征与源位图。
NOTSRCCOPY
拷贝反转源位图到目标。
NOTSRCERASE
反转使用布尔OR *** 作符合并源和目标位图的结果。
PATCOPY
拷贝特征到目标位图。
PATINVERT
使用布尔XOR *** 作符合并目标位图和特征。
PATPAINT
使用布尔OR *** 作符合并反转源位图和特征。用布尔OR *** 作符合并这项 *** 作结果与目标位图。
SRCAND
使用布尔AND *** 作符合并目标像素和源位图。
SRCCOPY
拷贝源位图到目标位图。
SRCERASE
反转目标位图并用布尔AND *** 作符合并这个结果和源位图。
SRCINVERT
使用布尔XOR *** 作符合并目标像素和源位图。
SRCPAINT
使用布尔OR *** 作符合并目标像素和源位图。
WHITENESS
所有输出变白。 有关光栅 *** 作代码的完整列表，请参阅联机文档“Win32
SDK程序员参考”附录节中的“关于光栅 *** 作代码”。
说明：
从源设备上下文拷贝位图到这个当前设备上下文。
应用可以在字节边界上对齐窗口或客户区域，保证BitBlt *** 作发生在以字节对齐的矩形上（登记窗口类时设置设备CS_BYTEALLGNWINDOW或CS_BYTEALIGHCLIENT标记）。
在字节对齐矩形上的BitBlt *** 作比未经字节对齐的矩形上的BitBlt *** 作快许多。汪让丛如果想对自己的设备上下文指定字节对齐类风格，必须登记窗口类而不要依赖Microsoft基本类。可使用全局函数AfxRegisterWndClass。
一旦使用目标设备上下文和使用源设备上下文，GDI变形nWidth和nHeight。如果结果延伸不匹配，必要时GDI使用Windows
StretchBlt函数压缩或拉伸源位图。
如果目标、源和特征位图颜色格式不同，BitBlt转换源和特征位图以匹配目标。转换中使用目标位图的前景和背景色。
BitBlt函数把单色位图转换为彩色时，它设置白色（1）为背景色，黑色（0）作为前景色。使用目标设备上下文的背景和前景色。要把彩色转换为单困樱色，BitBlt把与背景色匹配的像素设置为白色，其余所有像素设置为黑色。在从彩色到单色的转换中，BitBlt使用彩色设备上下文的前景和背景色。
注意，并非所有的设备上下文都支持BitBlt。为检查给定设备上下文是否支持BitBlt，使用GetDeviceCaps成员函数并指定RASTERCAPS索引。
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