http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSAffineTransform_Class/Reference/Reference.html
NSAffineTransform?
If you read the Drawing and Graphics documents on the developer website, they
talks about the view, its bounding box, and how to achieve ANY transformation
you need. This is 101 Linear algebra stuff, it doesn't matter where the origin
is, (in our limited case) there is some matrix which can transform you to any
other space you want/need, and it is doable using the NSAffineTransform.
> From: [email protected]
> Date: Thu, 3 Feb 2011 23:58:46 +0900
> To: [email protected]
> CC: [email protected]
> Subject: Re: origin: lower left vs lower right
>
>
> On Feb 3, 2011, at 8:51 PM, Uli Kusterer wrote:
>
> > On 03.02.2011, at 04:19, Todd Heberlein wrote:
> >> During the recent text orientation/position thread a couple of things
> >> caught my attention: (1) the text system seemed designed to have a flipped
> >> view (origin in the upper left), and (2) the iOS version of an NSView, the
> >> UIView, also has an origin in the upper left.
> >>
> >> If starting some new graphical code for Cocoa (which I may want to port
> >> parts of to iOS), is it advisable to use a flipped coordinate system
> >> (origin in upper left)? In other words, is "upper left" the origin of the
> >> future?
> >
> > It's not a matter of "the future" it is a matter of purpose. Mathematics
> > has traditionally had the origin in the lower left, so if you're working
> > with equations from textbooks, it is more convenient to leave the
> > coordinate system unflipped.
> >
> > However, historically human writing and the Mac user interface have had a
> > top-left to lower-right direction, so if you are laying out lists, or text,
> > or other sequences for humans, it is generally more convenient (and even
> > efficient) to use a flipped coordinate system. Otherwise, if you for
> > example resize a window, you have to manually adjust any content that is
> > aligned with the upper left, because when resizing an unflipped coordinate
> > system, the upper left corner has "moved", even though on a Mac the grow
> > box is in the lower right.
> >
> Not all human writing has a historical root in top-left to lower-right
> direction!
> In fact one area that is still a weakness, particularly for eBooks, is the
> lack of vertical top-right to lower-left text views in AppKit and UIKit.
> Literary texts are still written in this form in Japanese and Chinese.
> These writing systems are also not based on the same typographical concepts
> as western writing systems... they're based on a consistent square for each
> character.
> So in that regard, the coordinate system is also off.
>
>
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