#pragma comment(linker, "/subsystem:windows")#include <windows.h>// ----------------------------------------------------------------------------static HDC g_hDC = NULL;static HDC g_memDC = NULL;static HBITMAP g_memBM = NULL;static POINTS g_cPointsBegin = {0};static BOOL g_bDrawEnable = FALSE;// ----------------------------------------------------------------------------static void GetCurClientSize(HWND hWnd, int& nWidth, int& nHeight){ RECT rc = {0}; GetClientRect(hWnd, &rc); nWidth = rc.right - rc.left; nHeight = rc.bottom - rc.top;}static void ChangeMemDCSize(HWND hWnd, HDC hDC, HDC& memDC, HBITMAP& memBM){ if ( hWnd && hDC && memDC && memBM ) { int nWidth = 0; int nHeight = 0; GetCurClientSize(hWnd, nWidth, nHeight); HDC memDCNew = CreateCompatibleDC(hDC); HBITMAP memBMNew = CreateCompatibleBitmap(hDC, nWidth, nHeight); HBITMAP memBMOld = (HBITMAP)SelectObject(memDCNew, memBMNew); DeleteObject(memBMOld); HPEN hPen = CreatePen(PS_SOLID, 0, RGB(255,255,255)); HPEN hPenOld = (HPEN)SelectObject(memDCNew, hPen); DeleteObject(hPenOld); HBRUSH hBrush = CreateSolidBrush(RGB(255,255,255)); HBRUSH hBrushOld = (HBRUSH)SelectObject(memDCNew, hBrush); DeleteObject(hBrushOld); Rectangle(memDCNew, 0, 0, nWidth, nHeight); BitBlt( memDCNew, 0, 0, nWidth, nHeight, memDC, 0, 0, SRCCOPY ); DeleteObject(memBM); memBM = memBMNew; DeleteDC(memDC); memDC = memDCNew; }}// ----------------------------------------------------------------------------LRESULT MyInit(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ LRESULT ret = FALSE; g_hDC = GetDC(hWnd); if ( g_hDC != NULL ) { g_memDC = CreateCompatibleDC(g_hDC); if ( g_memDC != NULL ) { int nWidth = 0; int nHeight = 0; GetCurClientSize(hWnd, nWidth, nHeight); g_memBM = CreateCompatibleBitmap(g_hDC, nWidth, nHeight); if ( g_memBM != NULL ) { HBITMAP memBMOld = (HBITMAP)SelectObject(g_memDC, g_memBM); DeleteObject(memBMOld); SendMessage(hWnd, WM_KEYDOWN, VK_F1, 0); ret = TRUE; } } } return ret;}LRESULT UnInit(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ if ( g_memBM != NULL ) { DeleteObject(g_memBM); g_memBM = NULL; } if ( g_memDC != NULL ) { DeleteDC(g_memDC); g_memDC = NULL; } if ( g_hDC != NULL ) { ReleaseDC(hWnd, g_hDC); g_hDC = NULL; } return TRUE;}// ----------------------------------------------------------------------------LRESULT OnLButtonDown(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ g_cPointsBegin = MAKEPOINTS(lParam); g_bDrawEnable = TRUE; SetCapture(hWnd); return TRUE;}LRESULT OnMouseMove(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ if ( MK_LBUTTON == wParam ) { if ( g_bDrawEnable ) { POINTS pt = {0}; pt = MAKEPOINTS(lParam); SendMessage(hWnd, WM_PAINT, 0, 0); MoveToEx(g_hDC, g_cPointsBegin.x, g_cPointsBegin.y, NULL); LineTo(g_hDC, pt.x, pt.y); } } return TRUE;}LRESULT OnLButtonUp(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ if ( TRUE == g_bDrawEnable ) { g_bDrawEnable = FALSE; POINTS pt = {0}; pt = MAKEPOINTS(lParam); HPEN hPen = CreatePen(PS_SOLID, 0, RGB(0,255,0)); HPEN hPenOld = (HPEN)SelectObject(g_memDC, hPen); MoveToEx(g_memDC, g_cPointsBegin.x, g_cPointsBegin.y, NULL); LineTo(g_memDC, pt.x, pt.y); SelectObject(g_memDC, hPenOld); DeleteObject(hPen); SendMessage(hWnd, WM_PAINT, 0, 0); } ReleaseCapture(); return TRUE;}// ----------------------------------------------------------------------------LRESULT OnKeyDown(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ if ( VK_F1 == wParam ) { if ( g_memDC != NULL ) { int nWidth = 0; int nHeight = 0; GetCurClientSize(hWnd, nWidth, nHeight); HPEN hPen = CreatePen(PS_SOLID, 0, RGB(255,255,255)); HPEN hPenOld = (HPEN)SelectObject(g_memDC, hPen); HBRUSH hBrush = CreateSolidBrush(RGB(255,255,255)); HBRUSH hBrushOld = (HBRUSH)SelectObject(g_memDC, hBrush); Rectangle(g_memDC, 0, 0, nWidth, nHeight); SelectObject(g_memDC, hPenOld); DeleteObject(hPen); SelectObject(g_memDC, hBrushOld); DeleteObject(hBrush); InvalidateRect(hWnd, NULL, TRUE); } } else if ( VK_ESCAPE == wParam ) { SendMessage(hWnd, WM_CLOSE, 0, 0); } return TRUE;}// ----------------------------------------------------------------------------LRESULT OnCreate(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ return MyInit(hWnd, message, wParam, lParam);}LRESULT OnClose(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ UnInit(hWnd, message, wParam, lParam); DestroyWindow(hWnd); return TRUE;}LRESULT OnSize(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ if ( SIZE_MINIMIZED != wParam ) { ChangeMemDCSize(hWnd, g_hDC, g_memDC, g_memBM); } return TRUE;}LRESULT OnPaint(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ if ( g_hDC != NULL && g_memDC != NULL ) { int nWidth = 0; int nHeight = 0; GetCurClientSize(hWnd, nWidth, nHeight); BitBlt( g_hDC, 0, 0, nWidth, nHeight, g_memDC, 0, 0, SRCCOPY ); } return TRUE;}LRESULT OnOtherMessage(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ switch (message) { case WM_LBUTTONDOWN: OnLButtonDown(hWnd, message, wParam, lParam); break; case WM_MOUSEMOVE: OnMouseMove(hWnd, message, wParam, lParam); break; case WM_LBUTTONUP: OnLButtonUp(hWnd, message, wParam, lParam); break; case WM_KEYDOWN: OnKeyDown(hWnd, message, wParam, lParam); break; } return TRUE;}// ----------------------------------------------------------------------------LRESULT CALLBACK MainWndProc( HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam){ switch (message) { case WM_CREATE: if ( TRUE != OnCreate(hWnd, message, wParam, lParam) ) { SendMessage(hWnd, WM_CLOSE, 0, 0); } break; case WM_CLOSE: OnClose(hWnd, message, wParam, lParam); break; case WM_SIZE: OnSize(hWnd, message, wParam, lParam); break; case WM_PAINT: OnPaint(hWnd, message, wParam, lParam); break; case WM_DESTROY: PostQuitMessage(0); break; default: OnOtherMessage(hWnd, message, wParam, lParam); break; } return DefWindowProc(hWnd, message, wParam, lParam);}// ----------------------------------------------------------------------------int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow){ MSG msg; BOOL bRet; WNDCLASS wc; UNREFERENCED_PARAMETER(lpCmdLine); // Register the main window class. wc.style = CS_HREDRAW | CS_VREDRAW; wc.lpfnWndProc = (WNDPROC)MainWndProc; wc.cbClsExtra = 0; wc.cbWndExtra = 0; wc.hInstance = hInstance; wc.hIcon = LoadIcon(NULL, IDI_APPLICATION); wc.hCursor = LoadCursor(NULL, IDC_ARROW); wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); wc.lpszMenuName = NULL; wc.lpszClassName = "MyDraw"; if ( !RegisterClass(&wc) ) { return FALSE; } HWND hWnd = CreateWindow( wc.lpszClassName, "画图板", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL ); if ( NULL == hWnd ) { return FALSE; } ShowWindow(hWnd, nCmdShow); UpdateWindow(hWnd); while ( (bRet = GetMessage(&msg, NULL, 0, 0)) != 0 ) { if ( -1 == bRet ) { // handle the error and possibly exit return FALSE; } else { TranslateMessage(&msg); DispatchMessage(&msg); } } // Return the exit code to the system. return msg.wParam;}
