设计并实现时钟类Clock

void CClockView::OnDraw(CDC* pDC) { CClockDoc* pDoc = GetDocument(); ASSERT_VALID(pDoc); // Get the client rectangle so that we // can dynamically fit the clock to // the window. RECT Rect; GetClientRect( &Rect ); // For easier calculations, get the // x and y coordinates of the // window center. int nCenterX = Rect.right / 2; int nCenterY = Rect.bottom / 2; // Get the current time. CTime Time = CTime::GetCurrentTime(); CString strDigits; int i, x, y; CSize size; switch( m_nClockType ){ case CLOCK_ANALOG: { // Create a yellow pen with which we'll // draw the ellipse. CPen Pen( PS_SOLID, 5, RGB( 255, 255, 0 ) ); // Select the new pen into the DC and // remember the pen that was selected out. CPen *pOldPen = pDC->SelectObject( &Pen ); // Draw the clock face border with // the Ellipse function. pDC->Ellipse( 5, 5, Rect.right - 5, Rect.bottom - 5 ); double Radians; // Out text color will be red. pDC->SetTextColor( RGB( 255, 0, 0 ) ); for( i=1; i<=12; i++ ){ // Format the digit CString object // for the current clock number. strDigits.Format( "%d", i ); // Get the text extent of the // text so that we can center // it about a point. size = pDC->GetTextExtent( strDigits, strDigits.GetLength() ); // Calculate the number of radians // for the current clock number. Radians = (double) i * 6.28 / 12.0; // Calculate the x coordinate. We // use the text extent to center // the text about a point. x = nCenterX - ( size.cx / 2 ) + (int) ( (double) ( nCenterX - 20 ) * sin( Radians ) ); // Calculate the y coordinate. We // use the text extent to center // the text about a point. y = nCenterY - ( size.cy / 2 ) - (int) ( (double) ( nCenterY - 20 ) * cos( Radians ) ); // Draw the text. pDC->TextOut( x, y, strDigits ); } // Calculate the radians for the hour hand. Radians = (double) Time.GetHour() + (double) Time.GetMinute() / 60.0 + (double) Time.GetSecond() / 3600.0; Radians *= 6.28 / 12.0; // Create a pen for the hour hand that's five // pixels wide with a green color. CPen HourPen( PS_SOLID, 5, RGB( 0, 255, 0 ) ); // Select the newly-created CPen object // into the DC. pDC->SelectObject( &HourPen ); // Move to the center of the clock, then // draw the hour hand line. pDC->MoveTo( nCenterX, nCenterY ); pDC->LineTo( nCenterX + (int) ( (double) ( nCenterX / 3 ) * sin( Radians ) ), nCenterY - (int) ( (double) ( nCenterY / 3 ) * cos( Radians ) ) ); // Calculate the radians for the minute hand. Radians = (double) Time.GetMinute() + (double) Time.GetSecond() / 60.0; Radians *= 6.28 / 60.0; // Create a pen for the minute hand that's three // pixels wide with a blue color. CPen MinutePen( PS_SOLID, 3, RGB( 0, 0, 255 ) ); // Select the newly-created CPen object // into the DC. pDC->SelectObject( &MinutePen ); // Move the to center of the clock, then // draw the minute hand line. pDC->MoveTo( nCenterX, nCenterY ); pDC->LineTo( nCenterX + (int) ( (double) ( ( nCenterX * 2 ) / 3 ) * sin( Radians ) ), nCenterY - (int) ( (double) ( ( nCenterY * 2 ) / 3 ) * cos( Radians ) ) ); // Calculate the radians for the second hand. Radians = (double) Time.GetSecond(); Radians *= 6.28 / 60.0; // Create a pen for the second hand that's one // pixels wide with a cyan color. CPen SecondPen( PS_SOLID, 1, RGB( 0, 255, 255 ) ); // Select the newly-created CPen object // into the DC. pDC->SelectObject( &SecondPen ); // Move the to center of the clock, then // draw the second hand line. pDC->MoveTo( nCenterX, nCenterY ); pDC->LineTo( nCenterX + (int) ( (double) ( ( nCenterX * 4 ) / 5 ) * sin( Radians ) ), nCenterY - (int) ( (double) ( ( nCenterY * 4 ) / 5 ) * cos( Radians ) ) ); // Select the old CPen object back into // the DC. pDC->SelectObject( pOldPen ); } break; case CLOCK_DIGITAL: { // Begin by creating the text string // that represents the digital time. strDigits.Format( "%d:%02d:%02d", Time.GetHour(), Time.GetMinute(), Time.GetSecond() ); CFont Font, *pOldFont; int nWidth = 100; int nHeight = 140; do{ // We may have already created // a font in the CFont object. Here // we make sure it's deleted. if( Font.GetSafeHandle() != NULL ) Font.DeleteObject(); // Create the font with mostly default // values. Use a Times New Roman font. Font.CreateFont( nHeight, nWidth, 0, 0, FW_DONTCARE, 0, 0, 0, ANSI_CHARSET, OUT_CHARACTER_PRECIS, CLIP_CHARACTER_PRECIS, DEFAULT_QUALITY, DEFAULT_PITCH | FF_DONTCARE, "Times New Roman" ); // Select the newly-created CFont object into // the DC and remember the CFont object that // was selected out. pOldFont = pDC->SelectObject( &Font ); // Get the text extent so we can decide if // this font is too large. size = pDC->GetTextExtent( strDigits, strDigits.GetLength() ); // Select the old font back into the DC. pDC->SelectObject( pOldFont ); // If the text extent is too wide, // reduce the font width. if( size.cx > Rect.right ) nWidth -= 5; // If the text extent is too high, // reduce the font height. if( size.cy > Rect.bottom ) nHeight -= 5; } while( size.cx > Rect.right || size.cy > Rect.bottom ); // Select the final font into the // DC and remember the CFont object // that's selected out. pOldFont = pDC->SelectObject( &Font ); // Draw the text. pDC->TextOut( nCenterX - ( size.cx / 2 ), nCenterY - ( size.cy / 2 ), strDigits ); // Select the old font back into the DC. pDC->SelectObject( pOldFont ); } break; } } void CClockView::OnTimer(UINT nIDEvent) { // The timer just causes a redraw to occur. // In the OnDraw() function the current // time is obtained. InvalidateRect( NULL, TRUE ); UpdateWindow(); CView::OnTimer(nIDEvent); }

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