Re: Confusion about screen resolution

[Rick Aurbach via Cocoa-dev]

Transposition type indeed! Thanks for catching it. (If you check my 
calculations, I was clearly using 72 pt/in)

Cheers,

Rick Aurbach
8233 Tulane Avenue
St. Louis, MO 63132

eMail: rla...@icloud.com
Phone:   314/721-7987

“The single biggest problem in communication is the illusion that it has taken 
place.”
– George Bernard Shaw (1856–1950)


> On Feb 22, 2020, at 3:36 PM, Marco S Hyman  wrote:
> 
>> 
>> But a typographical  point is a unit of distance. There are 27 points per 
>> inch. (I.e., a typographical point is 0.0139 inches or 0.353 mm).
> 
> Transposition typo? There are 72 points/inch.  The given inch and mm values 
> are correct if rounded to 3 digits.

___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com

Re: Confusion about screen resolution

[Rick Aurbach via Cocoa-dev]

> Message: 1
> Date: Sat, 22 Feb 2020 14:24:40 +0100
> From: Gabriel Zachmann mailto:z...@cs.uni-bremen.de>>
> To: "cocoa-dev@lists.apple.com " 
> mailto:cocoa-dev@lists.apple.com>>
> Subject: Confusion about screen resolution
> Message-ID:  >
> Content-Type: text/plain; charset=us-ascii
> 
> When my screensaver gets invoked by the screensaver engine, it calls 
> - (id) initWithFrame: (NSRect) frameRect isPreview: (BOOL) preview
> 
> Funny thing is, when I print the frameRect to the log, I get  1680 x 1050.
> But my laptop screen really has 2880 x 1800!  (That's what I get from "About 
> this Mac")
> 
> I am running under Catalina 10.15.3.
> 
> 
> Can any one please shed some light on this?
> 
> Thanks a lot in advance.
> Gab.
> 

Gab,

I think you are confusing pixels and points.

A pixel is an addressable light-emitting area on the screen. Your screen 
contains 2880 X 1800 pixels.

But a typographical  point is a unit of distance. There are 27 points per inch. 
(I.e., a typographical point is 0.0139 inches or 0.353 mm).

Recalling that screen sizes are measured diagonally, the diagonal of a 1680pt  
X 1050pt rectangle is 1981pt (or 27 inches). I conclude that your Mac has a 
27-inch screen at a resolution of 123 X 123 px/in.

Cheers,

Rick Aurbach
8233 Tulane Avenue
St. Louis, MO 63132

eMail: rla...@icloud.com
Phone:   314/721-7987

H-A-R-D-W-A-R-E
(noun)

“The part of a computer you can kick."
___

Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)

Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com

Help/Unsubscribe/Update your Subscription:
https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com

This email sent to arch...@mail-archive.com