Task: draw a clock. More specific:
-
- Draw a time keeping device. It can be a stopwatch, hourglass, sundial, a mouth counting “one thousand and one”, anything. Only showing the seconds is required, e.g. a watch with just a second hand will suffice. However, it must clearly change every second, and the change must cycle every so often (one minute, 30 seconds, etc.) It must be drawn; printing a string of numbers to your terminal doesn’t qualify. Both text-based and graphical drawing are OK.
- The clock is unlikely to be used to control space flights, so it needs not be hyper-accurate, but it should be usable, meaning if one can read the seconds off the clock, it must agree with the system clock.
- A clock is rarely (never?) a major application: don’t be a CPU hog and poll the system timer every microsecond, use a proper timer/signal/event from your system or language instead. For a bad example, many OpenGL programs update the framebuffer in a busy loop even if no redraw is needed, which is very undesirable for this task.
- A clock is rarely (never?) a major application: try to keep your code simple and to the point. Don’t write something too elaborate or convoluted, instead do whatever is natural, concise and clear in your language.
#include <windows.h> #include <string> #include <math.h> //-------------------------------------------------------------------------------------------------- using namespace std; //-------------------------------------------------------------------------------------------------- const int BMP_SIZE = 300, MY_TIMER = 987654, CENTER = BMP_SIZE >> 1, SEC_LEN = CENTER - 20, MIN_LEN = SEC_LEN - 20, HOUR_LEN = MIN_LEN - 20; const float PI = 3.1415926536f; //-------------------------------------------------------------------------------------------------- class vector2 { public: vector2() { x = y = 0; } vector2( int a, int b ) { x = a; y = b; } void set( int a, int b ) { x = a; y = b; } void rotate( float angle_r ) { float _x = static_cast<float>( x ), _y = static_cast<float>( y ), s = sinf( angle_r ), c = cosf( angle_r ), a = _x * c - _y * s, b = _x * s + _y * c; x = static_cast<int>( a ); y = static_cast<int>( b ); } int x, y; }; //-------------------------------------------------------------------------------------------------- class myBitmap { public: myBitmap() : pen( NULL ), brush( NULL ), clr( 0 ), wid( 1 ) {} ~myBitmap() { DeleteObject( pen ); DeleteObject( brush ); DeleteDC( hdc ); DeleteObject( bmp ); } bool create( int w, int h ) { BITMAPINFO bi; ZeroMemory( &bi, sizeof( bi ) ); bi.bmiHeader.biSize = sizeof( bi.bmiHeader ); bi.bmiHeader.biBitCount = sizeof( DWORD ) * 8; bi.bmiHeader.biCompression = BI_RGB; bi.bmiHeader.biPlanes = 1; bi.bmiHeader.biWidth = w; bi.bmiHeader.biHeight = -h; HDC dc = GetDC( GetConsoleWindow() ); bmp = CreateDIBSection( dc, &bi, DIB_RGB_COLORS, &pBits, NULL, 0 ); if( !bmp ) return false; hdc = CreateCompatibleDC( dc ); SelectObject( hdc, bmp ); ReleaseDC( GetConsoleWindow(), dc ); width = w; height = h; return true; } void clear( BYTE clr = 0 ) { memset( pBits, clr, width * height * sizeof( DWORD ) ); } void setBrushColor( DWORD bClr ) { if( brush ) DeleteObject( brush ); brush = CreateSolidBrush( bClr ); SelectObject( hdc, brush ); } void setPenColor( DWORD c ) { clr = c; createPen(); } void setPenWidth( int w ) { wid = w; createPen(); } void saveBitmap( string path ) { BITMAPFILEHEADER fileheader; BITMAPINFO infoheader; BITMAP bitmap; DWORD wb; GetObject( bmp, sizeof( bitmap ), &bitmap ); DWORD* dwpBits = new DWORD[bitmap.bmWidth * bitmap.bmHeight]; ZeroMemory( dwpBits, bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD ) ); ZeroMemory( &infoheader, sizeof( BITMAPINFO ) ); ZeroMemory( &fileheader, sizeof( BITMAPFILEHEADER ) ); infoheader.bmiHeader.biBitCount = sizeof( DWORD ) * 8; infoheader.bmiHeader.biCompression = BI_RGB; infoheader.bmiHeader.biPlanes = 1; infoheader.bmiHeader.biSize = sizeof( infoheader.bmiHeader ); infoheader.bmiHeader.biHeight = bitmap.bmHeight; infoheader.bmiHeader.biWidth = bitmap.bmWidth; infoheader.bmiHeader.biSizeImage = bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD ); fileheader.bfType = 0x4D42; fileheader.bfOffBits = sizeof( infoheader.bmiHeader ) + sizeof( BITMAPFILEHEADER ); fileheader.bfSize = fileheader.bfOffBits + infoheader.bmiHeader.biSizeImage; GetDIBits( hdc, bmp, 0, height, ( LPVOID )dwpBits, &infoheader, DIB_RGB_COLORS ); HANDLE file = CreateFile( path.c_str(), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL ); WriteFile( file, &fileheader, sizeof( BITMAPFILEHEADER ), &wb, NULL ); WriteFile( file, &infoheader.bmiHeader, sizeof( infoheader.bmiHeader ), &wb, NULL ); WriteFile( file, dwpBits, bitmap.bmWidth * bitmap.bmHeight * 4, &wb, NULL ); CloseHandle( file ); delete [] dwpBits; } HDC getDC() const { return hdc; } int getWidth() const { return width; } int getHeight() const { return height; } private: void createPen() { if( pen ) DeleteObject( pen ); pen = CreatePen( PS_SOLID, wid, clr ); SelectObject( hdc, pen ); } HBITMAP bmp; HDC hdc; HPEN pen; HBRUSH brush; void *pBits; int width, height, wid; DWORD clr; }; //-------------------------------------------------------------------------------------------------- class clock { public: clock() { _bmp.create( BMP_SIZE, BMP_SIZE ); _bmp.clear( 100 ); _bmp.setPenWidth( 2 ); _ang = DegToRadian( 6 ); } void setNow() { GetLocalTime( &_sysTime ); draw(); } float DegToRadian( float degree ) { return degree * ( PI / 180.0f ); } void setHWND( HWND hwnd ) { _hwnd = hwnd; } private: void drawTicks( HDC dc ) { vector2 line; _bmp.setPenWidth( 1 ); for( int x = 0; x < 60; x++ ) { line.set( 0, 50 ); line.rotate( static_cast<float>( x + 30 ) * _ang ); MoveToEx( dc, CENTER - static_cast<int>( 2.5f * static_cast<float>( line.x ) ), CENTER - static_cast<int>( 2.5f * static_cast<float>( line.y ) ), NULL ); LineTo( dc, CENTER - static_cast<int>( 2.81f * static_cast<float>( line.x ) ), CENTER - static_cast<int>( 2.81f * static_cast<float>( line.y ) ) ); } _bmp.setPenWidth( 3 ); for( int x = 0; x < 60; x += 5 ) { line.set( 0, 50 ); line.rotate( static_cast<float>( x + 30 ) * _ang ); MoveToEx( dc, CENTER - static_cast<int>( 2.5f * static_cast<float>( line.x ) ), CENTER - static_cast<int>( 2.5f * static_cast<float>( line.y ) ), NULL ); LineTo( dc, CENTER - static_cast<int>( 2.81f * static_cast<float>( line.x ) ), CENTER - static_cast<int>( 2.81f * static_cast<float>( line.y ) ) ); } } void drawHands( HDC dc ) { float hp = DegToRadian( ( 30.0f * static_cast<float>( _sysTime.wMinute ) ) / 60.0f ); int h = ( _sysTime.wHour > 12 ? _sysTime.wHour - 12 : _sysTime.wHour ) * 5; _bmp.setPenWidth( 3 ); _bmp.setPenColor( RGB( 0, 0, 255 ) ); drawHand( dc, HOUR_LEN, ( _ang * static_cast<float>( 30 + h ) ) + hp ); _bmp.setPenColor( RGB( 0, 128, 0 ) ); drawHand( dc, MIN_LEN, _ang * static_cast<float>( 30 + _sysTime.wMinute ) ); _bmp.setPenWidth( 2 ); _bmp.setPenColor( RGB( 255, 0, 0 ) ); drawHand( dc, SEC_LEN, _ang * static_cast<float>( 30 + _sysTime.wSecond ) ); } void drawHand( HDC dc, int len, float ang ) { vector2 line; line.set( 0, len ); line.rotate( ang ); MoveToEx( dc, CENTER, CENTER, NULL ); LineTo( dc, line.x + CENTER, line.y + CENTER ); } void draw() { HDC dc = _bmp.getDC(); _bmp.setBrushColor( RGB( 250, 250, 250 ) ); Ellipse( dc, 0, 0, BMP_SIZE, BMP_SIZE ); _bmp.setBrushColor( RGB( 230, 230, 230 ) ); Ellipse( dc, 10, 10, BMP_SIZE - 10, BMP_SIZE - 10 ); drawTicks( dc ); drawHands( dc ); _bmp.setPenColor( 0 ); _bmp.setBrushColor( 0 ); Ellipse( dc, CENTER - 5, CENTER - 5, CENTER + 5, CENTER + 5 ); _wdc = GetDC( _hwnd ); BitBlt( _wdc, 0, 0, BMP_SIZE, BMP_SIZE, dc, 0, 0, SRCCOPY ); ReleaseDC( _hwnd, _wdc ); } myBitmap _bmp; HWND _hwnd; HDC _wdc; SYSTEMTIME _sysTime; float _ang; }; //-------------------------------------------------------------------------------------------------- class wnd { public: wnd() { _inst = this; } int wnd::Run( HINSTANCE hInst ) { _hInst = hInst; _hwnd = InitAll(); SetTimer( _hwnd, MY_TIMER, 1000, NULL ); _clock.setHWND( _hwnd ); ShowWindow( _hwnd, SW_SHOW ); UpdateWindow( _hwnd ); MSG msg; ZeroMemory( &msg, sizeof( msg ) ); while( msg.message != WM_QUIT ) { if( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) != 0 ) { TranslateMessage( &msg ); DispatchMessage( &msg ); } } return UnregisterClass( "_MY_CLOCK_", _hInst ); } private: void wnd::doPaint( HDC dc ) { _clock.setNow(); } void wnd::doTimer() { _clock.setNow(); } static int WINAPI wnd::WndProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam ) { switch( msg ) { case WM_DESTROY: PostQuitMessage( 0 ); break; case WM_PAINT: { PAINTSTRUCT ps; HDC dc = BeginPaint( hWnd, &ps ); _inst->doPaint( dc ); EndPaint( hWnd, &ps ); return 0; } case WM_TIMER: _inst->doTimer(); break; default: return DefWindowProc( hWnd, msg, wParam, lParam ); } return 0; } HWND InitAll() { WNDCLASSEX wcex; ZeroMemory( &wcex, sizeof( wcex ) ); wcex.cbSize = sizeof( WNDCLASSEX ); wcex.style = CS_HREDRAW | CS_VREDRAW; wcex.lpfnWndProc = ( WNDPROC )WndProc; wcex.hInstance = _hInst; wcex.hCursor = LoadCursor( NULL, IDC_ARROW ); wcex.hbrBackground = ( HBRUSH )( COLOR_WINDOW + 1 ); wcex.lpszClassName = "_MY_CLOCK_"; RegisterClassEx( &wcex ); RECT rc = { 0, 0, BMP_SIZE, BMP_SIZE }; AdjustWindowRect( &rc, WS_SYSMENU | WS_CAPTION, FALSE ); int w = rc.right - rc.left, h = rc.bottom - rc.top; return CreateWindow( "_MY_CLOCK_", ".: Clock -- PJorente :.", WS_SYSMENU, CW_USEDEFAULT, 0, w, h, NULL, NULL, _hInst, NULL ); } static wnd* _inst; HINSTANCE _hInst; HWND _hwnd; clock _clock; }; wnd* wnd::_inst = 0; //-------------------------------------------------------------------------------------------------- int APIENTRY _tWinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow ) { wnd myWnd; return myWnd.Run( hInstance ); } //--------------------------------------------------------------------------------------------------
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