Re: Event Objects Return 1-Based Y Coordinate Values
Re: Event Objects Return 1-Based Y Coordinate Values
- Subject: Re: Event Objects Return 1-Based Y Coordinate Values
- From: Bill Cheeseman <email@hidden>
- Date: Mon, 27 Jun 2011 14:00:12 -0400
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@hidden
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