用GDI+制作不规则窗体

1.

#define TRANS_COLOR         (ALPHA_MASK | RGB(255, 0, 255))

BOOL CMyDialog::OnInitDialog()
{
    CDialog::OnInitDialog();

    CRgn rgn;
    CreateRgnByImage(_T("MyImage.png"), rgn);
    SetWindowRgn(rgn, TRUE);

    return TRUE;
}

void CMyDialog::CreateRgnByImage(const CString &imageName, CRgn &rgn)
{
    Bitmap img(imageName);
    ASSERT(PixelFormat32bppARGB == img.GetPixelFormat());

    Rect rect(0, 0, img.GetWidth(), img.GetHeight());
    BitmapData data;
    img.LockBits(&rect, ImageLockModeRead, PixelFormat32bppARGB, &data);
    UINT *pData = static_cast<UINT*>(data.Scan0);

    rgn.CreateRectRgn(0, 0, 0, 0);

    CRgn tempRgn;
    for (UINT h = 0; h < data.Height; ++ h)
    {
        UINT w = 0;
        while(w < data.Width)
        {
            UINT leftX;
            while (w ++ < data.Width && TRANS_COLOR == *pData ++);
            leftX = w;
            while (w ++ < data.Width && TRANS_COLOR != *pData ++);

            tempRgn.CreateRectRgn(leftX, h, w - 1, h + 1);
            rgn.CombineRgn(&rgn, &tempRgn, RGN_OR);
            tempRgn.DeleteObject();
        }
    }

    img.UnlockBits(&data);
}

2.

如果使用一幅位图，通过挖图的方式来做成一个不规则的窗体，是很累人的一件事。

  而使用GDI+，可以直接用PNG图片，通过图片本身的透明度，自动创建不规则窗体。

  比如，你手中有个美女图，通过PhotoShop等工具，把美女的身体抠出来，保存为PNG格式的图片，除了美女的身体，图片的其他部门都是透明的。后面的工作就是，写一个windows小程序，加载这幅美女图，让她成为我们程序的界面。

 

  Win32程序的框架我就懒得贴了，直接贴关键代码了。

 view plain#include<GdiPlus.h>  

 using namespace Gdiplus;

 #define MAX_LOADSTRING 100
 //Gdiplus start up params
 ULONG_PTR m_gdiplusToken;
 GdiplusStartupInput m_gdiplusStartupInput;
 //rendering prarams
 BLENDFUNCTION m_Blend;
 //images
 Bitmap * m_BackgoundImage;
 int WINAPI WinMain(HINSTANCE hInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR    lpCmdLine,
                    int       nCmdShow)
 {
     //....
 }
 BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
 {
    //...
    return TRUE;
 }
 LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
     switch (message)
     {
     case WM_CREATE:
         {
             GdiplusStartup(&m_gdiplusToken, &m_gdiplusStartupInput, NULL);
             m_Blend.BlendOp     = AC_SRC_OVER;
             m_Blend.AlphaFormat = AC_SRC_ALPHA;
             m_Blend.BlendFlags  = 0;
             m_Blend.SourceConstantAlpha = 255;
             m_BackgoundImage = Bitmap::FromFile(L"meinv.png");
             if(m_BackgoundImage == NULL)
             {
                 MessageBox(hWnd, (LPCSTR)"it is null", (LPCSTR)"OO", 0);
                 exit(0);
             }

             int DesktopWidth  = GetSystemMetrics(SM_CXSCREEN);
             int DesktopHeight = GetSystemMetrics(SM_CYSCREEN);

             g_WindowWidth  = m_BackgoundImage->GetWidth();
             g_WindowHeight = m_BackgoundImage->GetHeight();

             int StartX = (DesktopWidth - g_WindowWidth)/2;
             int StartY = (DesktopHeight - g_WindowHeight)/2;
             SetWindowPos(hWnd, HWND_TOP, StartX, StartY ,g_WindowWidth, g_WindowHeight, SWP_DRAWFRAME);
         }
         break;
     case WM_PAINT:
         {
             UpdateWindowView(hWnd);
         }
         break;
         case WM_NCHITTEST:
         {
             PostMessage(hWnd, WM_LBUTTONDOWN, wParam, lParam);
             return HTCAPTION;
         }
         break;
     case WM_DESTROY:
             GdiplusShutdown(m_gdiplusToken);
         PostQuitMessage(0);
             break;
     default:
         return DefWindowProc(hWnd, message, wParam, lParam);
     }
     return 0;
 }
 void UpdateWindowView(HWND hWnd)
 {
     //window position
     RECT rct;
     GetWindowRect(hWnd, &rct);
     POINT ptWinPos = {rct.left,rct.top};
     SIZE szWinSize = {g_WindowWidth - 1, g_WindowHeight - 1};

     HDC dcScreen = GetDC(hWnd);
     HDC dcmemory = CreateCompatibleDC(dcScreen);

     HBITMAP canvas = CreateCompatibleBitmap(dcScreen, g_WindowWidth, g_WindowHeight);

     SelectObject(dcmemory, canvas);

     Graphics * graphics = Graphics::FromHDC(dcmemory);

     Point points[] =
     {
         Point(0, 0),
     Point(g_WindowWidth, 0),
     Point(0, g_WindowHeight)
     };
     graphics->DrawImage(m_BackgoundImage, points, 3);

     POINT ptSrc = {0, 0};

    //0x80000 是指WS_EX_LAYERED 宏值 ,下边两句可用 ModifyStyleEx(0, WS_EX_LAYERED);代替
     DWORD dwExStyle = GetWindowLong(hWnd, GWL_EXSTYLE);
     if((dwExStyle&0x80000) != 0x80000)
     {
         SetWindowLong(hWnd, GWL_EXSTYLE, dwExStyle^0x80000);
     }

     BOOL res = UpdateLayeredWindow(hWnd, dcScreen, &ptWinPos, &szWinSize, dcmemory, &ptSrc, 0, &m_Blend, ULW_ALPHA);
     DWORD dw = GetLastError();
     delete graphics;

     DeleteObject(canvas);
     canvas = NULL;

     //Create出来的dc要用DeleteDC来释放,Get到的要用ReleaseDC释放
     DeleteDC(dcmemory);
     ReleaseDC(hWnd, dcScreen);
     /*最后的这些资源一定记得释放，不然内存泄漏很严重，窗体在拖动的时候很慢。*/
 }

 

  不过呢，这么做也有个不爽的地方，你使用的PNG图片必须也和你的程序一起发布，不能隐藏在程序代码中。当然了一般的游戏都是有专门的资源包，并且做了加密的。我看剑侠叁的启动界面应该就是使用GDI+来做的，很漂亮。

另:

//可实现透明效果, 
ModifyStyleEx(0, WS_EX_LAYERED);
SetLayeredWindowAttributes(0,220,LWA_ALPHA);