Example 3: Obtaining the Window Coordinates

This example shows the use of AcGiViewportDraw::polylineDc() and AcGiViewport::getViewportDcCorners() to obtain the display coordinates of the viewport. This function is convenient when you are drawing graphics that depend on the physical layout of the viewport, such as icons and markers that vary with the size or borders of the viewport. The graphics drawn will change with panning and zooming.

The example draws a box in the upper-right corner of the viewport. The box's width and height are always one-tenth of the viewport's shortest dimension, and the box is centered one-tenth of the viewport's shortest dimension down and to the left of the upper-right-hand corner of the viewport:

      void     
      AsdkIconSamp::subViewportDraw(AcGiViewportDraw* pV)     
 { 
      // Get the       current viewport's display coordinates.     
 // 
      AcGePoint2d       lower_left, upper_right;     
      pV->viewport       ().getViewportDcCorners(lower_left,     
      upper_right);     
  
      double xsize =       upper_right.x - lower_left.x;     
      double ysize =       upper_right.y - lower_left.y;     
  
      xsize /= 10.0;     
      ysize /= 10.0;     
  
      double xcenter       = upper_right.x - xsize;     
      double ycenter       = upper_right.y - ysize;     
  
      double       half_xsize = xsize / 2.0;     
      double       half_ysize = ysize / 2.0;     
  
      // Create a       unit square.     
 // 
      const int       num_verts = 5;     
  
      AcGePoint3d       verts[num_verts];     
  
      for (int i = 0;       i < num_verts; i++) {     
      verts[i].x =       xcenter;     
      verts[i].y =       ycenter;     
      verts[i].z =       0.0;     
 } 
      verts[0].x -=       half_xsize;     
      verts[0].y +=       half_ysize;     
      verts[1].x +=       half_xsize;     
      verts[1].y +=       half_ysize;     
      verts[2].x +=       half_xsize;     
      verts[2].y -=       half_ysize;     
      verts[3].x -=       half_xsize;     
      verts[3].y -=       half_ysize;     
  
      verts[4] =       verts[0];     
  
      pV-       >subEntityTraits().setColor(kRed);     
  
      pV->geometry       ().polylineDc(num_verts, verts);     
 } 

void
AsdkIconSamp::viewportDraw(AcGiViewportDraw* pV)
{
    // Get the current viewport's display coordinates.
    //
    AcGePoint2d lower_left, upper_right;
    pV->viewport().getViewportDcCorners(lower_left,
        upper_right);
    double xsize = upper_right.x - lower_left.x;
    double ysize = upper_right.y - lower_left.y;
    xsize /= 10.0;
    ysize /= 10.0;
    double xcenter = upper_right.x - xsize;
    double ycenter = upper_right.y - ysize;
    double half_xsize = xsize / 2.0;
    double half_ysize = ysize / 2.0;
    // Create a unit square.
    //
    const int num_verts = 5;
    AcGePoint3d verts[num_verts];
    for (int i = 0; i < num_verts; i++) {
        verts[i].x = xcenter;
        verts[i].y = ycenter;
        verts[i].z = 0.0;
    }
    verts[0].x -= half_xsize;
    verts[0].y += half_ysize;
    verts[1].x += half_xsize;
    verts[1].y += half_ysize;
    verts[2].x += half_xsize;
    verts[2].y -= half_ysize;
    verts[3].x -= half_xsize;
    verts[3].y -= half_ysize;
    verts[4] = verts[0];
    pV->subEntityTraits().setColor(kRed);
    pV->geometry().polylineDc(num_verts, verts);
}