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Q106161: How to Convert Screen Object Positions Between Platforms

Article: Q106161
Product(s): Microsoft FoxPro
Version(s): MACINTOSH:2.5b; WINDOWS:2.5,2.5a,2.5b,3.0
Operating System(s): 
Keyword(s): 
Last Modified: 05-FEB-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 3.0 
- Microsoft FoxPro for Windows, versions 2.5, 2.5a, 2.5b 
- Microsoft FoxPro for Macintosh, version 2.5b 
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SUMMARY
=======

When you transport FoxPro applications between character-based and graphic-
based environments, you must convert the row and column positions of screen
objects appropriately, as explained below.

MORE INFORMATION
================

In FoxPro for MS-DOS, objects are placed based on row and column positions. The
size of each row and column remains constant, since only one screen font is
available. However, in FoxPro for Windows and FoxPro for the Macintosh, row and
column sizes will vary based on the current font and the current resolution of
the screen.

In order to provide a consistent unit of measurement and accurate placement of
objects between platforms, foxels were developed. Foxels are simply fractional
rows and columns, expressed in decimal form. A foxelrow is used to indicate a
single vertical row of characters. A foxelcol is used to indicate a single
horizontal character.

The size of a foxelrow will vary depending on the height of the current font. The
number of foxelrows available can be determined with the SROWS() function. The
size of a foxelcol will vary depending on the average width of characters in the
current font. The number of foxelcols available can be determined with the
SCOLS() function.

The algorithm to determine pixel-to-foxel conversion is:

     FUNCTION _pix2fox
        PARAMETER m.apixel,m.dimension
        RETURN m.apixel/FONTMETRIC(IIF(UPPER(m.dimension) = "H",6,1))

The following two parameters are passed to the function:

- M.APIXEL indicates the pixel position.

- M.DIMENSION indicates a "V" for vertical values and an "H" for horizontal
  values.

Usage
-----

     myfoxelrow = _pix2fox(pixvalnum,"V") && for vertical (row) values
     myfoxelcol = _pix2fox(pixvalnum,"H") && for horizontal (col) values

The algorithm for foxelrows divides the pixel position by the character height in
pixels for the current font. The algorithm for foxelcols divides the pixel
position by the average character width in pixels for the current font.

Additional query words: VFoxWin FoxMac FoxWin 2.50 floating transport

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Keywords          :  
Technology        : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbFoxproSearch kbFoxPro250bMac kbFoxPro250 kbFoxPro250a kbFoxPro250b kbVFP300
Version           : MACINTOSH:2.5b; WINDOWS:2.5,2.5a,2.5b,3.0

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