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/


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.