DrawOSDLine.c

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#include                "libFireBird.h"
 
void DrawOSDLine(word OSDRgn, dword Ax, dword Ay, dword Bx, dword By, dword Color)
{
  TRACEENTER();
 
  int dX, dY, Xincr, Yincr, dist, Xerr, Yerr, d;
 
  // distances
  dX = Bx - Ax;
  dY = By - Ay;
 
  // increments
  if(dX < 0)
  {
    dX = -dX;
    Xincr = -1;
  }
  else Xincr = (dX > 0 ? 1 : 0);
 
  if(dY < 0)
  {
    dY = -dY;
    Yincr = -1;
  }
  else Yincr = (dY > 0 ? 1 : 0);
 
  // longest distance
  dist = (dX > dY ? dX : dY);
 
  // initialize error terms
  Xerr = dX;
  Yerr = dY;
 
  // draw line
  for(d = 0; d < dist; d++)
  {
    TAP_Osd_PutPixel_Chk("DrawOSDLine A", OSDRgn, Ax, Ay, Color);   // plot the pixel
 
    Xerr += dX;
    Yerr += dY;
 
    if(Xerr > dist)
    {
      Xerr -= dist;
      Ax += Xincr;
    }
 
    if(Yerr > dist)
    {
      Yerr -= dist;
      Ay += Yincr;
    }
  }
 
  TAP_Osd_PutPixel_Chk("DrawOSDLine B", OSDRgn, Bx, By, Color);   // plot the pixel
 
  TRACEEXIT();
}