kicad/include/convert_to_biu.h

#ifndef CONVERT_TO_BIU_H_
#define CONVERT_TO_BIU_H_

#include <config.h>     // USE_PCBNEW_NANOMETRES is defined here

/**
 * @file convert_to_biu.h
 */


/**
 * @brief some define and functions to convert a value in mils, decimils or mm
 * to the internal unit used in pcbnew, cvpcb or gerbview (nanometer or deci-mil)
 * depending on compile time option
 */



/// Scaling factor to convert mils to internal units.
#if defined(PCBNEW) || defined(CVPCB) || defined(GERBVIEW)
 #if defined( USE_PCBNEW_NANOMETRES )
  #if defined(GERBVIEW)
   #define IU_PER_MM        1e5     // Gerbview uses 10 micrometer.
  #else
   #define IU_PER_MM        1e6     // Pcbnew uses nanometers.
  #endif
  #define IU_PER_MILS       (IU_PER_MM * 0.0254)
  #define IU_PER_DECIMILS   (IU_PER_MM * 0.00254)

 #else                              // Pcbnew compiled for deci-mils.
  #define IU_PER_DECIMILS   1
  #define IU_PER_MILS       10.0
  #define IU_PER_MM         (1e4 / 25.4)
 #endif

/// Convert mils to PCBNEW internal units (iu).
inline int Mils2iu( int mils )
{
#if defined( USE_PCBNEW_NANOMETRES )
    double x = mils * IU_PER_MILS;
    return int( x < 0 ? x - 0.5 : x + 0.5 );
#else
    return mils * IU_PER_MILS;
#endif
}

/// Convert deci-mils to PCBNEW internal units (iu).
inline int DMils2iu( int dmils )
{
#if defined( USE_PCBNEW_NANOMETRES )
    double x = dmils * IU_PER_DECIMILS;
    return int( x < 0 ? x - 0.5 : x + 0.5 );
#else
    return dmils;
#endif
}

#else            // Eeschema and anything else.

#define IU_PER_DECIMILS     0.1
#define IU_PER_MILS         1.0
#define IU_PER_MM           (IU_PER_MILS / 0.0254)

inline int Mils2iu( int mils )
{
    return mils;
}
#endif

#endif  // CONVERT_TO_BIU_H_