A TXPBAR with GDI+ for MFC

• Download source code - 3.4 MB

Introduction

This is an XP dockbar program like Apple's dockbar. It switches scrolling with a flip animation effect.

Using the code

Step 1. This step inludes loading the library "User32.DLL" for the "UpdateLayeredWindow" function. This is a per-pixel-alpha transparence. Therefore, we have no more jagged edges.

hFuncInst = LoadLibrary("User32.DLL"); 
BOOL bRet=FALSE;
if(hFuncInst){ 
    UpdateLayeredWindow=(MYFUNC)GetProcAddress(hFuncInst, "UpdateLayeredWindow");
}
else
{
    AfxMessageBox("User32.dll ERROR!");
    exit(0);
}

Step 2. Initialize GDI+.

m_Blend.BlendOp=0; //the only BlendOp defined in Windows2000
m_Blend.BlendFlags=0; //nothing else isspecial...
m_Blend.AlphaFormat=1;
m_Blend.SourceConstantAlpha=255;//AC_SRC_ALPHA

Step 3. Now, the DrawTXBar function.

void DrawTXBar()
{
    DWORD dwExStyle=GetWindowLong(m_hWnd,GWL_EXSTYLE);
    if((dwExStyle&0x80000)!=0x80000)
    SetWindowLong(m_hWnd,GWL_EXSTYLE,dwExStyle^0x80000);
    BOOL bRet=FALSE;
    bRet= UpdateLayeredWindow( m_hWnd,hdcScreen,&ptWinPos, 
          &sizeWindow,m_hdcMemory,&ptSrc,0,&m_Blend,2);
    //UpdateLayeredWindow" must By execute 
    //one hypo- one to Update the alpha window's Image.
    ...
}

Points of interest

The API function "UpdateLayeredWindow" must by executed to update the alpha window's image.