Computer Graphics1 Windows NT Graphics Interface

Computer Graphics2 References n Since a complete study of the Windows NT programming isn’t possible within the time limits we have, for additional information you can use any of the following: u Windows 95 Programming Nuts & Bolts for experienced Programmers / Herbert Schildt u Microsoft Visual C++ X.X help. u Any other windows NT programming guides.

Computer Graphics3 Some Application Fundamentals n WinMain int WINAPI WinMain( HINSTANCE hInstance, // handle to current instance HINSTANCE hInstance, // handle to current instance HINSTANCE hPrevInstance, // handle to previous // instance HINSTANCE hPrevInstance, // handle to previous // instance LPSTR lpCmdLine,// pointer to command line int nCmdShow // show state of window ); u All Windows NT programs begin execution with a call to WinMain(), except for console applications, which begin in main().

Computer Graphics4 Some Application Fundamentals n The Window Function u All Windows NT programs must contain a special function that is not called by your program, but is called by Windows NT. u It is through this function that Windows communicates with your program. The window function is called whenever Windows needs to pass a “message” to your program. u Example: ViewProc(HWND hWnd, UINT wMessage, UINT wParam, LONG lParam) UINT wParam, LONG lParam)

Computer Graphics5 Some Application Fundamentals u It is passed the first four members of the MSG structure as parameters: n Message structure: typedef struct tagMSG { HWND wnd;// window that message is for UINT message; // message WPARAM wParam; // message-dependent info LPARAM lParam;// more message-dependent info DWORD time;// time message posted POINT pt;// x,y location of mouse } MSG;

Computer Graphics6 Message Macros WM_PAINT - WM_PAINT - Windows or another application makes a request to paint a portion of an application's window. WM_LBUTTONUP - WM_LBUTTONUP - the user releases the left mouse button while the cursor is in the client area of a window. WM_LBUTTONDOWN - WM_LBUTTONDOWN - the user presses the left mouse button while the cursor is in the client area of a window. WM_MOUSEMOVE - WM_MOUSEMOVE - the cursor moves

Computer Graphics7 Drawing in Windows NT: n HDC - Device Context u Contains the information on the way it is possible to draw on the screen: F color (background, foreground) F Paint structure F Pen F Other info. n HPEN - Type of pen to draw lines on the screen u line color u line width u line style

Computer Graphics8 Drawing in Windows NT - Cont. n To get the default pen of the screen: HPEN hPen = SelectObject(hDC,GetStockObject(BLACK_PEN)); n Drawing a line: u Moving a pen to location (x,y): MoveToEx(hDC, x, y, NULL); MoveToEx(hDC, x, y, NULL); u Drawing a line from the current point to (x,y): LineTo(hDC, x, y);

Computer Graphics9 Toolbar n A Toolbar is One of the most important common controls because it can speed up menu selection when you are using a mouse. n Often, a Toolbar is used in conjunction with a standard menu. n To create a Tollbar, use the CreateToolbarEx() function: HWND CreateToolbarEx( HWND hwnd, DWORD ws,UINT wID, int nBitmaps, HINSTANCE hBMInst, UINT wBMID, LPCTBBUTTON lpButtons, int iNumButtons, int dxButton, int dyButton, int dxBitmap, int dyBitmap, UINT uStructSize );

Computer Graphics10 Example n In your header file, there should be definitions for the names of the buttons you are using, so that they can be identified when pressed. For example, in Skeleton.h: #define CG_TOOLBAR (WM_USER) #define CG_PERSP (CG_TOOLBAR + 1) #define CG_ORTHO (CG_TOOLBAR + 2) n Also, the style of each button, and the way they appear is determined in a TBBUTTON struct.

Computer Graphics11 TBBUTTON typedef struct _TBBUTTON { int iBitmap;// int iBitmap;// Zero-based index of button image int idCommand; // int idCommand; // Command identifier associated with // the button BYTE fsState; // BYTE fsState; // Button state flags BYTE fsStyle; // BYTE fsStyle; // Button style DWORD dwData; // DWORD dwData; // Application-defined value. int iString; // int iString; // Zero-based index of button string. } TBBUTTON, NEAR* PTBBUTTON, FAR* LPTBBUTTON; FAR* LPTBBUTTON;

Computer Graphics12 TBBUTTON - Cont. n For example, in Skeleton.C: static TBBUTTON tbButtons[] = { { 0, 0, TBSTATE_ENABLED, TBSTYLE_SEP }, { 0, CG_ORTHO, TBSTATE_ENABLED | TBSTATE_CHECKED, TBSTYLE_CHECKGROUP }, { 1, CG_PERSP, TBSTATE_ENABLED, TBSTYLE_CHECKGROUP }, { 0, 0, TBSTATE_ENABLED, TBSTYLE_SEP }, TBSTYLE_SEP }, { 2, CG_ROTAT, TBSTATE_ENABLED | TBSTATE_CHECKED, TBSTYLE_CHECKGROUP },... { 8, CG_SAVE, TBSTATE_ENABLED, TBSTYLE_BUTTON }, { 8, CG_SAVE, TBSTATE_ENABLED, TBSTYLE_BUTTON },...

Computer Graphics13 Summarize of the exercises skeleton n In the skeleton, 2 windows are created. The first (szAppName) is initially 512x512, and contains a tool bar child, and contains a child window (szViewName). n The parent window is not seen, but it handles the messages that are sent from the tool bar, any time a button is pressed. n The child window receives the messages of the mouse pressing and moving, which cause the calls to the functions that you will have to write.