elements.cpp

Beginning Visual C++ 6源码。Wrox。

// Implementations of the element classes
#include "stdafx.h"

#include <math.h>

#include "OurConstants.h"
#include "Elements.h"

// CLine class constructor
CLine::CLine(const CPoint& Start, const CPoint& End, const COLORREF& Color)
{
   m_StartPoint = Start;      // Set line start point
   m_EndPoint = End;          // Set line end point
   m_Color = Color;           // Set line color
   m_Pen = 1;                 // Set pen width

   // Define the enclosing rectangle
   m_EnclosingRect = CRect(Start, End);
   m_EnclosingRect.NormalizeRect();
}

// Draw a CLine object
void CLine::Draw(CDC* pDC) const
{
   // Create a pen for this object and
   // initialize it to the object color and line width
   CPen aPen;
   if(!aPen.CreatePen(PS_SOLID, m_Pen, m_Color))
   {
      // Pen creation failed. Abort the program
      AfxMessageBox("Pen creation failed drawing a line", MB_OK);
      AfxAbort();
   }

   CPen* pOldPen = pDC->SelectObject(&aPen);  // Select the pen

   // Now draw the line
   pDC->MoveTo(m_StartPoint);
   pDC->LineTo(m_EndPoint);

   pDC->SelectObject(pOldPen);                // Restore the old pen
}

// Get the bounding rectangle for an element
CRect CElement::GetBoundRect() const
{
   CRect BoundingRect;              // Object to store bounding rectangle
   BoundingRect = m_EnclosingRect;  // Store the enclosing rectangle

   // Increase the rectangle by the pen width
   BoundingRect.InflateRect(m_Pen, m_Pen);

   return BoundingRect;             // Return the bounding rectangle
}

// CRectangle class constructor
CRectangle:: CRectangle(const CPoint& Start, const CPoint& End, const COLORREF& Color)
{
   m_Color = Color;           // Set rectangle color
   m_Pen = 1;          // Set pen width

   // Define the enclosing rectangle 
   m_EnclosingRect = CRect(Start, End);
   m_EnclosingRect.NormalizeRect();
}

// Draw a CRectangle object
void CRectangle::Draw(CDC* pDC) const
{
   // Create a pen for this object and
   // initialize it to the object color and line width
   CPen aPen;
   if (!aPen.CreatePen(PS_SOLID, m_Pen, m_Color))
   { 
      // Pen creation failed
      AfxMessageBox("Pen creation failed drawing a rectangle", MB_OK);
      AfxAbort();
   }

   // Select the pen
   CPen* pOldPen = pDC->SelectObject(&aPen);   
   // Select the brush
   CBrush* pOldBrush = static_cast<CBrush*>(pDC->SelectStockObject(NULL_BRUSH)); 

   // Now draw the rectangle
   pDC->Rectangle(m_EnclosingRect);

   pDC->SelectObject(pOldBrush);              // Restore the old brush
   pDC->SelectObject(pOldPen);                // Restore the old pen
}

// Constructor for a circle object
CCircle::CCircle(const CPoint& Start, const CPoint& End, const COLORREF& Color)
{
   // First calculate the radius
   // We use floating point because that is required by 
   // the library function (in math.h) for calculating a square root.
   long Radius = 
        static_cast<long>(sqrt(static_cast<double>((End.x-Start.x)*(End.x-Start.x)+
                                                   (End.y-Start.y)*(End.y-Start.y))));

   // Now calculate the rectangle enclosing
   // the circle assuming the MM_TEXT mapping mode
   m_EnclosingRect = CRect(Start.x - Radius, Start.y - Radius,
                           Start.x + Radius, Start.y + Radius);

   m_Color = Color;          // Set the color for the circle
   m_Pen = 1;         // Set pen width
}

// Draw a circle
void CCircle::Draw(CDC* pDC) const
{
   // Create a pen for this object and
   // initialize it to the object color and line width
   CPen aPen;
   if (!aPen.CreatePen(PS_SOLID, m_Pen, m_Color))
   {
      // Pen creation failed
      AfxMessageBox("Pen creation failed drawing a circle", MB_OK);
      AfxAbort();
   }

   CPen* pOldPen = pDC->SelectObject(&aPen);  // Select the pen

   // Select a null brush
   CBrush* pOldBrush = static_cast<CBrush*>(pDC->SelectStockObject(NULL_BRUSH)); 

   // Now draw the circle
   pDC->Ellipse(m_EnclosingRect);

   pDC->SelectObject(pOldPen);                // Restore the old pen
   pDC->SelectObject(pOldBrush);              // Restore the old brush
}

// Constructor for a curve object
CCurve::CCurve(const COLORREF& Color)
{
   m_Color = Color;                    // Store the color
   m_EnclosingRect = CRect(0,0,0,0);
   m_Pen = 1;                   // Set pen width
}

// Draw a curve
void CCurve::Draw(CDC* pDC) const
{
}


// Add definitions for member functions here