On Jun 27, 2011, at 1:26 PM, Raleigh Ledet wrote:

> Cocoa coordinates are all 0,0 based. If you have a reproducible test case 
> that says otherwise, please file a radar and attach it.
> 
> -raleigh
> 
> 
> On Jun 25, 2011, at 7:59 AM, Richard Somers wrote:
> 
>> The Cocoa Drawing Guide states "Cocoa event objects return y coordinate 
>> values that are 1-based instead of 0-based. Thus, a mouse click on the 
>> bottom left corner of a window or view would yield the point (0, 1) in Cocoa 
>> and not (0, 0). Only y-coordinates are 1-based."
>> 
>> Why are the y-coordianate values of Cocoa event objects 1-based?
>> 
>> Do most developers simply subtract 1.0 from the y-coordianate value obtained 
>> from an event object to make it 0-based before using the x-y-coordinate val


I think the OP misunderstood the document. Although Cocoa coordinates are 
0-based, the 0 point on the Y axis of the screen is just beyond the bottom of 
the screen. That is, if you click at the bottom of the screen, the Y coordinate 
will be 1. 0 is still a valid Y coordinate. I'm not aware that programmers make 
any overall adjustments of coordinates for this. They just remember that the 
bottommost clickable Y coordinate is 0.

-- 

Bill Cheeseman - [email protected]

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