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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