Use an algorithm to implement dash line with a line width not 1

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#include <math.h>void DrawDashLine(CDC* pDC, LPPOINT ptStart, LPPOINT ptEnd,                  int nWidht, COLORREF crLine){  CPen pen(PS_DASH, nWidht, crLine);  CPen *pOldPen = pDC->SelectObject(&pen);    double k = (double)(ptEnd->y - ptStart->y)/(double)(ptEnd->x - ptStart->x);  double b = ptEnd->y - k * ptEnd->x;   double fAngle = atan(k);  int dashLinLen = 10; //  double ptDash_x = dashLinLen * cos(fAngle),  ptDash_y = dashLinLen * sin(fAngle);  double ptSpace_x = ptDash_x, ptSpace_y = ptDash_y;  double pt1_x = ptStart->x, pt1_y = ptStart->y;  while(pt1_x < ptEnd->x)  {    pDC->MoveTo((int)pt1_x, (int)pt1_y);    double pt2_x = pt1_x + ptDash_x, pt2_y = pt1_y + ptDash_y;    if(pt2_x > ptEnd->x)    {      pt2_x = ptEnd->x, pt2_y = ptEnd->y;    }    pDC->LineTo((int)pt2_x, (int)pt2_y);    pt1_x += ptDash_x + ptSpace_x;    pt1_y += ptDash_y + ptSpace_y;  }  pDC->SelectObject(pOldPen);}

 

// Test code void csdi_44view: ondraw (CDC * PDC) {csdi_44doc * pdoc = getdocument (); assert_valid (pdoc); // todo: add draw code for native data here crect rcclient; getclientrect (& rcclient); drawdashline (PDC, & rcclient. topleft (), & rcclient. bottomright (), 5, RGB (255, 0, 0 ));}

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