Tkinter: winfo_screenmmwidth discussion

[josefg at gmail.com]

On Tuesday, November 26, 2013 2:55:52 PM UTC-8, Dennis Lee Bieber wrote:
> On Tue, 26 Nov 2013 14:13:57 -0800 (PST), josefg at gmail.com declaimed the
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> following:
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> >I am currently using Windows 7 Sp1, Tkinter 8.5, Python 2.7.4 on a laptop with no attached monitor. I am attempting to use winfo_screenmmwidth, but the returned value is incorrect. Specs state 280 mm. Physical measurement is 275 mm. EDID states 280 mm. Tkinter's winfo_screenmmwidth returns 361 mm. I don't have very much tkinter experience, please bear with me.
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> >
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> 	Windows systems used to be quite lax on monitor size... Two monitors of
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> physically different sizes having the same pixel dimensions could possibly
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> report as being the same width. Especially if one is not using 100% for
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> text size and for DPI setting.
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> 	My current monitor is 20.5 inches across (by steel tape measure), but
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> Windows defaults to 96DPI... Which comes to a 20 inch width when using
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> 1920x1200 (native mode). The real resolution is 93.66DPI (while my previous
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> computer ran a clean 100DPI <G>)
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> -- 
> 
> 	Wulfraed                 Dennis Lee Bieber         AF6VN
> 
>     wlfraed at ix.netcom.com    HTTP://wlfraed.home.netcom.com/
    
    "Windows systems used to be quite lax on monitor size... Two monitors of
physically different sizes having the same pixel dimensions could possibly
report as being the same width."

Check your monitor's EDID bytes 21 (max horizontal mm) and 22 (max vertical mm). Those should be accurate regardless of OS and current resolution setting.