win32用GDI+加载png图片作为背景图

1. #include <windows.h>


2. #include <gdiplus.h>
3. /* GDI+ startup token */


4. ULONG_PTR gdiplusStartupToken;
5. /* Declare Windows procedure */


6. LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
7. // UpdateLayeredWindow Defination


8. typedef
   BOOL(*UPDATELAYEREDWINDOWFUNCTION)(HWND,HDC,POINT*,SIZE*,HDC,POINT*,COLORREF,BLENDFUNCTION*,DWORD);
9. /* Make the class name into a global variable */


10. char szClassName[ ] = "PNGDialog";
11. int WINAPI WinMain (HINSTANCE hThisInstance,


12. HINSTANCE hPrevInstance,


13. LPSTR lpszArgument,


14. int nCmdShow)


15. {
16. /**/


17. Gdiplus::GdiplusStartupInput gdiInput;


18. Gdiplus::GdiplusStartup(&gdiplusStartupToken,&gdiInput,NULL);


19. /**/


20. HWND hwnd; /* This is the handle for our window */


21. MSG messages; /* Here messages to the application are saved
    */


22. WNDCLASSEX wincl; /* Data structure for the windowclass */
23. /* The Window structure */


24. wincl.hInstance = hThisInstance;


25. wincl.lpszClassName = szClassName;//+-69+


26. wincl.lpfnWndProc = WindowProcedure; /* This function is
    called by windows */


27. wincl.style = CS_DBLCLKS; /* Catch double-clicks */


28. wincl.cbSize = sizeof (WNDCLASSEX);
29. /* Use default icon and mouse-pointer */


30. wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);


31. wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);


32. wincl.hCursor = LoadCursor (NULL, IDC_ARROW);


33. wincl.lpszMenuName = NULL; /* No menu */


34. wincl.cbClsExtra = 0; /* No extra bytes after the window class */


35. wincl.cbWndExtra = 0; /* structure or the window instance
    */


36. /* Use Windows‘s default colour as the background of the window */


37. wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;
38. /* Register the window class, and if it fails quit the program
    */


39. if (!RegisterClassEx (&wincl))


40. return 0;
41. /* The class is registered, let‘s create the program*/


42. hwnd = CreateWindowEx (


43. WS_EX_LAYERED|WS_EX_TOPMOST|WS_EX_TOOLWINDOW, /* Extended
    possibilites for variation */


44. szClassName, /* Classname */


45. "PNGDialog Example Application", /* Title Text */


46. WS_OVERLAPPEDWINDOW, /* default window */


47. CW_USEDEFAULT, /* Windows decides the position */


48. CW_USEDEFAULT, /* where the window ends up on the screen */


49. 500, /* The programs width */


50. 500, /* and height in pixels */


51. HWND_DESKTOP, /* The window is a child-window to desktop
    */


52. NULL, /* No menu */


53. hThisInstance, /* Program Instance handler */


54. NULL /* No Window Creation data */


55. );
56. /* Make the window visible on the screen */


57. ShowWindow (hwnd, nCmdShow);


58. LONG style = ::GetWindowLong(hwnd,GWL_STYLE);


59. if(style&WS_CAPTION)


60. style^=WS_CAPTION;


61. if(style&WS_THICKFRAME)


62. style^=WS_THICKFRAME;


63. if(style&WS_SYSMENU)


64. style^=WS_SYSMENU;


65. ::SetWindowLong(hwnd,GWL_STYLE,style);
66. style = ::GetWindowLong(hwnd,GWL_EXSTYLE);


67. if(style&WS_EX_APPWINDOW)


68. style^=WS_EX_APPWINDOW;


69. ::SetWindowLong(hwnd,GWL_EXSTYLE,style);
70. /********************************************


71. * step 1.


72. * Using Gdiplus to load the image


73. ********************************************/


74. RECT wndRect;


75. ::GetWindowRect(hwnd,&wndRect);


76. SIZE wndSize =
    {wndRect.right-wndRect.left,wndRect.bottom-wndRect.top};


77. HDC hdc = ::GetDC(hwnd);


78. HDC memDC = ::CreateCompatibleDC(hdc);


79. HBITMAP memBitmap =
    ::CreateCompatibleBitmap(hdc,wndSize.cx,wndSize.cy);


80. ::SelectObject(memDC,memBitmap);
81. Gdiplus::Image image(L"pic.png");


82. Gdiplus::Graphics graphics(memDC);


83. graphics.DrawImage(&image,0,0,wndSize.cx,wndSize.cy);


84. /********************************************


85. * step 2.


86. * Get "UpdateLayeredWindow" function‘s


87. * proc address.


88. ********************************************/


89. HMODULE hUser32 = ::LoadLibrary("User32.dll");


90. if(!hUser32)


91. {


92. return FALSE;


93. }


94. UPDATELAYEREDWINDOWFUNCTION UpdateLayeredWindow =
    (UPDATELAYEREDWINDOWFUNCTION)::GetProcAddress(hUser32,"UpdateLayeredWindow");


95. if(!UpdateLayeredWindow)


96. {


97. return FALSE;


98. }


99. // get screen dc


100. HDC screenDC = GetDC(NULL);


101. POINT ptSrc = {0,0};
102. /*********************************************


103. * step 3.


104. * Use UpdateLayeredWindow to Draw the Window


105. *


106. *********************************************/


107. BLENDFUNCTION blendFunction;


108. blendFunction.AlphaFormat = AC_SRC_ALPHA;


109. blendFunction.BlendFlags = 0;


110. blendFunction.BlendOp = AC_SRC_OVER;


111. blendFunction.SourceConstantAlpha = 255;


112. UpdateLayeredWindow(hwnd,screenDC,&ptSrc,&wndSize,memDC,&ptSrc,0,&blendFunction,2);
113. ::DeleteDC(memDC);


114. ::DeleteObject(memBitmap);
115. /* Run the message loop. It will run until GetMessage() returns 0 */


116. while (GetMessage (&messages, NULL, 0, 0))


117. {


118. /* Translate virtual-key messages into character messages
     */


119. TranslateMessage(&messages);


120. /* Send message to WindowProcedure */


121. DispatchMessage(&messages);


122. }


123. Gdiplus::GdiplusShutdown(gdiplusStartupToken);


124. /* The program return-value is 0 - The value that
     PostQuitMessage() gave */


125. return messages.wParam;


126. }
127. /* This function is called by the Windows function DispatchMessage()
     */
128. LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam,
     LPARAM lParam)


129. {


130. switch (message) /* handle the messages */


131. {


132. case WM_DESTROY:


133. PostQuitMessage (0); /* send a WM_QUIT to the message queue
     */


134. break;


135. case WM_LBUTTONDOWN:


136. //::SendMessage(hwnd,WM_HIT)


137. break;


138. default: /* for messages that we don‘t deal with */


139. return DefWindowProc (hwnd, message, wParam, lParam);


140. }


141. return 0;


142. }

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