1. #include <windows.h>
2. #include <gdiplus.h>
4. /* GDI+ startup token */
5. ULONG_PTR gdiplusStartupToken;
7. /* Declare Windows procedure */
8. LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);
10. // UpdateLayeredWindow Defination
11. typedef BOOL(*UPDATELAYEREDWINDOWFUNCTION)(HWND,HDC,POINT*,SIZE*,HDC,POINT*,COLORREF,BLENDFUNCTION*,DWORD);
13. /* Make the class name into a global variable */
14. char szClassName[ ] = "PNGDialog";
16. int WINAPI WinMain (HINSTANCE hThisInstance,
17. HINSTANCE hPrevInstance,
18. LPSTR lpszArgument,
19. int nCmdShow)
20. {
22. /**/
23. Gdiplus::GdiplusStartupInput gdiInput;
24. Gdiplus::GdiplusStartup(&gdiplusStartupToken,&gdiInput,NULL);
25. /**/
26. HWND hwnd; /* This is the handle for our window */
27. MSG messages; /* Here messages to the application are saved */
28. WNDCLASSEX wincl; /* Data structure for the windowclass */
30. /* The Window structure */
31. wincl.hInstance = hThisInstance;
32. wincl.lpszClassName = szClassName;//+-69+
33. wincl.lpfnWndProc = WindowProcedure; /* This function is called by windows */
34. wincl.style = CS_DBLCLKS; /* Catch double-clicks */
35. wincl.cbSize = sizeof (WNDCLASSEX);
37. /* Use default icon and mouse-pointer */
38. wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
39. wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
40. wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
41. wincl.lpszMenuName = NULL; /* No menu */
42. wincl.cbClsExtra = 0; /* No extra bytes after the window class */
43. wincl.cbWndExtra = 0; /* structure or the window instance */
44. /* Use Windows‘s default colour as the background of the window */
45. wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;
47. /* Register the window class, and if it fails quit the program */
48. if (!RegisterClassEx (&wincl))
49. return 0;
51. /* The class is registered, let‘s create the program*/
52. hwnd = CreateWindowEx (
53. WS_EX_LAYERED|WS_EX_TOPMOST|WS_EX_TOOLWINDOW, /* Extended possibilites for variation */
54. szClassName, /* Classname */
55. "PNGDialog Example Application", /* Title Text */
56. WS_OVERLAPPEDWINDOW, /* default window */
57. CW_USEDEFAULT, /* Windows decides the position */
58. CW_USEDEFAULT, /* where the window ends up on the screen */
59. 500, /* The programs width */
60. 500, /* and height in pixels */
61. HWND_DESKTOP, /* The window is a child-window to desktop */
62. NULL, /* No menu */
63. hThisInstance, /* Program Instance handler */
64. NULL /* No Window Creation data */
65. );
67. /* Make the window visible on the screen */
68. ShowWindow (hwnd, nCmdShow);
69. LONG style = ::GetWindowLong(hwnd,GWL_STYLE);
70. if(style&WS_CAPTION)
71. style^=WS_CAPTION;
72. if(style&WS_THICKFRAME)
73. style^=WS_THICKFRAME;
74. if(style&WS_SYSMENU)
75. style^=WS_SYSMENU;
76. ::SetWindowLong(hwnd,GWL_STYLE,style);
78. style = ::GetWindowLong(hwnd,GWL_EXSTYLE);
79. if(style&WS_EX_APPWINDOW)
80. style^=WS_EX_APPWINDOW;
81. ::SetWindowLong(hwnd,GWL_EXSTYLE,style);
83. /********************************************
84. * step 1.
85. * Using Gdiplus to load the image
86. ********************************************/
87. RECT wndRect;
88. ::GetWindowRect(hwnd,&wndRect);
89. SIZE wndSize = {wndRect.right-wndRect.left,wndRect.bottom-wndRect.top};
90. HDC hdc = ::GetDC(hwnd);
91. HDC memDC = ::CreateCompatibleDC(hdc);
92. HBITMAP memBitmap = ::CreateCompatibleBitmap(hdc,wndSize.cx,wndSize.cy);
93. ::SelectObject(memDC,memBitmap);
95. Gdiplus::Image image(L"pic.png");
96. Gdiplus::Graphics graphics(memDC);
97. graphics.DrawImage(&image,0,0,wndSize.cx,wndSize.cy);
98. /********************************************
99. * step 2.
100. * Get "UpdateLayeredWindow" function‘s
101. * proc address.
102. ********************************************/
103. HMODULE hUser32 = ::LoadLibrary("User32.dll");
104. if(!hUser32)
105. {
106. return FALSE;
107. }
108. UPDATELAYEREDWINDOWFUNCTION UpdateLayeredWindow = (UPDATELAYEREDWINDOWFUNCTION)::GetProcAddress(hUser32,"UpdateLayeredWindow");
109. if(!UpdateLayeredWindow)
110. {
111. return FALSE;
112. }
113. // get screen dc
114. HDC screenDC = GetDC(NULL);
115. POINT ptSrc = http://www.mamicode.com/{0,0};
117. /*********************************************
118. * step 3.
119. * Use UpdateLayeredWindow to Draw the Window
120. *
121. *********************************************/
122. BLENDFUNCTION blendFunction;
123. blendFunction.AlphaFormat = AC_SRC_ALPHA;
124. blendFunction.BlendFlags = 0;
125. blendFunction.BlendOp = AC_SRC_OVER;
126. blendFunction.SourceConstantAlpha = 255;
127. UpdateLayeredWindow(hwnd,screenDC,&ptSrc,&wndSize,memDC,&ptSrc,0,&blendFunction,2);
129. ::DeleteDC(memDC);
130. ::DeleteObject(memBitmap);
132. /* Run the message loop. It will run until GetMessage() returns 0 */
133. while (GetMessage (&messages, NULL, 0, 0))
134. {
135. /* Translate virtual-key messages into character messages */
136. TranslateMessage(&messages);
137. /* Send message to WindowProcedure */
138. DispatchMessage(&messages);
139. }
140. Gdiplus::GdiplusShutdown(gdiplusStartupToken);
141. /* The program return-value is 0 - The value that PostQuitMessage() gave */
142. return messages.wParam;
143. }
146. /* This function is called by the Windows function DispatchMessage() */
148. LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
149. {
150. switch (message) /* handle the messages */
151. {
152. case WM_DESTROY:
153. PostQuitMessage (0); /* send a WM_QUIT to the message queue */
154. break;
155. case WM_LBUTTONDOWN:
156. //::SendMessage(hwnd,WM_HIT)
157. break;
158. default: /* for messages that we don‘t deal with */
159. return DefWindowProc (hwnd, message, wParam, lParam);
160. }
161. return 0;
162. }

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