• Open Menu Close Menu
  • Apple
  • Shopping Bag
  • Apple
  • Mac
  • iPad
  • iPhone
  • Watch
  • TV
  • Music
  • Support
  • Search apple.com
  • Shopping Bag

Lists

Open Menu Close Menu
  • Terms and Conditions
  • Lists hosted on this site
  • Email the Postmaster
  • Tips for posting to public mailing lists
Re: How to properly flip a UIView's coordinate system
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: How to properly flip a UIView's coordinate system


  • Subject: Re: How to properly flip a UIView's coordinate system
  • From: David Rowland <email@hidden>
  • Date: Sun, 22 Sep 2013 08:18:17 -0700

On Sep 22, 2013, at 4:20 AM, Dave <email@hidden> wrote:

>
> On 21 Sep 2013, at 21:38, Markus Spoettl <email@hidden> wrote:
>
>> Hi,
>>
>> I have a UIView on iOS that shares (a lot of) code with an NSView I have on OSX. That code relies on a LLO (lower left origin) coordinate system and it's not an option to change that.
>
> I'm in a similar position, in fact I have a lot of code that is ULO based and a lot of code that is LLO based. If I has only a single wish that would enable me to change something about Cocoa it would be that it always ULO or as a second wish that iOS used LLO as well.
>
> I'd really like to know why LLO was chosen for the Mac in the first place, and, why in iOS they chose to do the opposite?
>
> Anyone understand why/how this happened?

The earliest interface was the Teletype machine. It used a roll of low-grade paper and could print 80 characters on one line. Carriage return moved the print head to the first column, line feed moved the paper up one line.

The first electronic terminals were often "glass teletypes" with 80 columns and 24 rows. The cursor could be placed anywhere, and the convention was line 1 at the top and line 24 at the bottom. I believe that is where the inverted coordinates began. Bitmapped screens mimicked the TTY. Later creations like OpenGL respected the older, mathematical model, and we are now caught between.

David



_______________________________________________

Cocoa-dev mailing list (email@hidden)

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:

This email sent to email@hidden


  • Follow-Ups:
    • Re: How to properly flip a UIView's coordinate system
      • From: Dave <email@hidden>
References: 
 >How to properly flip a UIView's coordinate system (From: Markus Spoettl <email@hidden>)
 >Re: How to properly flip a UIView's coordinate system (From: Dave <email@hidden>)

  • Prev by Date: Re: How to properly flip a UIView's coordinate system
  • Next by Date: wrapping a really long word in an UILabel
  • Previous by thread: Re: How to properly flip a UIView's coordinate system
  • Next by thread: Re: How to properly flip a UIView's coordinate system
  • Index(es):
    • Date
    • Thread