方法二：用GDI＋(VC)
EVC下显示图片
用COM组件的 IPicture接口(VC)
在OnPaint 或 OnDraw中加入下代码即可 (注意 屏蔽掉 CXXDialog::OnPaint CXX::OnDraw)
dc.SetBkMode( TRANSPARENT );
CFile mFile;
LONG nLength;
//1 打开文件并获得文件的真实大小
if ( mFile.Open( _T( "./res/test.jpg" ),CFile::modeRead )
&&( ( nLength = mFile.GetLength() ) > 0 ) )
{
//2 从堆中分配指定数量字节的一整块，这时系统无法提供零零碎碎的局部或全局的堆
HGLOBAL hGlobal = GlobalAlloc(GMEM_MOVEABLE, nLength );
LPVOID pvData = NULL;
if ( hGlobal != NULL )
{
//3 锁定全局内存对象并返回它的首地址
if ( ( pvData = GlobalLock(hGlobal) ) != NULL )
{
//4 把文件内容读进全局内存对象的地址空间中
mFile.Read( pvData, nLength );
mFile.Close();
//5 GlobalUnlock函数把以GMEM_MOVEABLE方式分配的内存对象的锁定计数器减1
GlobalUnlock( hGlobal );
//6 从全局内存中创建stream对象，第二个参数指定当stream释放时是否自动释放全局内存
IStream *pStm;
CreateStreamOnHGlobal( hGlobal, TRUE, &pStm) ;
//7 创建一个新的picture对象并用stream对象中的内容初始化
IPicture *pPic;
if( SUCCEEDED( OleLoadPicture( pStm, nLength, TRUE, IID_IPicture, (LPVOID*)&pPic ) ) )
{
//8 释放不要的stream对象并清空stream指针
pStm->Release();
pStm=NULL;
OLE_XSIZE_HIMETRIC mWidth;
OLE_YSIZE_HIMETRIC mHeight;
//9 得到picture对象中图片的宽和高
pPic->get_Width( &mWidth );
pPic->get_Height( &mHeight );
CRect rc;
GetClientRect( &rc );
double fX,fY;
//10 GetDeviceCaps(HORZRES)得到屏幕的宽度(单位：像素)
// GetDeviceCaps(HORZSIZE)得到屏幕的宽度(单位：毫米)
fX = (double) dc.GetDeviceCaps(HORZRES) * (double)mWidth / ( (double)dc.GetDeviceCaps( HORZSIZE ) * 100.0 );
fY = (double) dc.GetDeviceCaps(VERTRES) * (double)mHeight / ( (double)dc.GetDeviceCaps( VERTSIZE ) *100.0 );
//11 把图像显示在dc中
if( FAILED( pPic->Render( dc.GetSafeHdc(), 0, 0, (DWORD)fX , (DWORD)fY , 0, mHeight, mWidth, -mHeight, NULL ) ) )
AfxMessageBox( _T("渲染图片失败") );
/*根据背景大小缩放图片
CRect rcClient;
GetClientRect( &rcClient );
BOOL bWidth = rcClient.Width() / fX > rcClient.Height() / fY;
if ( bWidth )
{
if( FAILED( pPic->Render( dc.GetSafeHdc(), 0, 0, (DWORD)rcClient.Width() , (DWORD)rcClient.Width() * fY / fX , 0, mHeight, mWidth, -mHeight, NULL ) ) )
AfxMessageBox( _T("渲染图片失败") );
}
else
{
if( FAILED( pPic->Render( dc.GetSafeHdc(), 0, 0, (DWORD)rcClient.Height() * fX/ fY, (DWORD)rcClient.Height() , 0, mHeight, mWidth, -mHeight, NULL ) ) )
AfxMessageBox( _T("渲染图片失败") );
}
*/
//12 释放不要的picture对象，并把指针清空
pPic->Release();
pPic=NULL;
//13 释放不要的全局内存对象，这个千万别忘了(32位程序不需要这行，系统会自动释放；16位程序一定要)
FreeResource(hGlobal);
}
else
AfxMessageBox( _T("从stream中装载图片失败") );
}
}
else
AfxMessageBox( _T("分配内存失败") );
}
else
AfxMessageBox( _T("打开文件失败") );
用GDI＋(VC)
添加Gdiplus.lib到工程中
头文件中添加
#include "Gdiplus.h"
using namespace Gdiplus;
添加类成员变量
GdiplusStartupInput m_gdiPlusInPut;
ULONG_PTR m_gdiPlusToken;
构造函数中初始化GDI+
GdiplusStartup( &m_gdiPlusToken, &m_gdiPlusInPut, NULL );
析构函数中 //销毁GDI+
GdiplusShutdown(gdiplusToken);
OnPaint()中
//CDialog::OnPaint();
CPaintDC dc( this );
//建立图形对象
Graphics mGraphics( dc.GetSafeHdc() );
//装入图像文件
Image img( L"./res/test.jpg", TRUE );
//在指定区域pdestPoints显示图像
/*//根据背景大小按比例缩放
CRect rcClient;
GetClientRect( &rcClient );
BOOL bWidth = rcClient.Width() / img.GetWidth() > rcClient.Height() / img.GetHeight();
if ( bWidth )
{
mGraphics.DrawImage( &img, 0, 0, rcClient.Width(), rcClient.Width() * img.GetHeight() / img.GetWidth() );
}
else
{
mGraphics.DrawImage(&img, 0, 0, rcClient.Height() * img.GetWidth() / img.GetHeight(), rcClient.Height() );
}
*/
//原始大小
mGraphics.DrawImage(&img, 0, 0, img.GetWidth(), img.GetHeight() );
EVC下显示图片:
void CXXDlg::OnPaint()
{
CPaintDC dc(this); // device context for painting
dc.SetBkMode( TRANSPARENT );
CBitmap mBitmap;
mBitmap.Attach( SHLoadImageFile( _T( "./player.jpg" ) ) );
BITMAP mInfo;
mBitmap.GetBitmap( &mInfo );
CDC mPicDC;
mPicDC.CreateCompatibleDC( &dc );
CBitmap* pOldBitmap = mPicDC.SelectObject( &mBitmap );
dc.BitBlt( 0, 0, mInfo.bmWidth, mInfo.bmHeight, &mPicDC, 0, 0, SRCCOPY );
mPicDC.SelectObject( pOldBitmap );
mBitmap.DeleteObject();
}