Converting between TWIPS and pixels (C++/MFC)

[burmair]

Most of you probably already know how to do this, but I just figured it out. If you're using MFC, the following C++ code can be used to convert between TWIPS and pixels.

(afxwin.h is the required header)

const int    TWIPS_PER_INCH       = 1440;
[...]
    inline int TwipsToPixels(int twips) { return (twips * m_devicePixelsPerInch / TWIPS_PER_INCH); }
    inline int PixelsToTwips(int pixels) { return (pixels * TWIPS_PER_INCH / m_devicePixelsPerInch); }
[...]
    int m_devicePixelsPerInch;
[...]
    // this code goes in the constructor
    CClientDC dc(this);  // 'this' is any CWnd-derived object
    m_devicePixelsPerInch = dc.GetDeviceCaps( LOGPIXELSY );

[Reallyethical]

but as your using fixed measurements you could just use constants like:

TwipsPerInch = 1440; {Same as minutes per day}
TwipsPerPixel = 15;
TwipsPerMil = 56.7;