[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Can we have convertTo/FromBase in view?
From: |
Banlu Kemiyatorn |
Subject: |
Re: Can we have convertTo/FromBase in view? |
Date: |
Sun, 26 Dec 2010 03:05:51 +0700 |
On Sun, Dec 26, 2010 at 12:33 AM, Quentin Mathé <address@hidden> wrote:
>
> NSView conversion methods requires both the receiver view and the argument
> view to be in the same view hierarchy (the Apple doc states they must belong
> to the same window).
I kinda use misguiding word, different hierarchy means they are not in
the same branch, only share an ancestor.
> It's unclear to me why GNUstep uses these two matrices 'fromWindow' and
> 'toWindow' per view rather than just having a 'superviewBoundsToFrame' matrix
> and a 'frameToBounds' matrix. Most UI toolkits seems to use this approach in
> their view hierararchy equivalent. I think it's more easy to debug geometry
> issues this way, and the drawing code would do less conversions when the view
> hierarchy is redrawn (based on what I remember from the NSView drawing code
> the last time I looked at it). Some cases would be more costly like
> invalidating drawing areas, but based on some tests I have done, this is
> negligible even with a complex view hierarchy and many invalidations, when
> compared to the time spent in the geometry conversions during a recursive
> redraw.
> Am I overlooking something or are there some special advantages with the
> current approach?
Not sure I understand this correctly, I think if you didn't store
fromWindow, toWindow and store conversion and inversion to superview,
then to convert a point you may need to keep multiplying a few
superviews until it reach the root, which could be a few matrix
multiplications. But most likely views are pretty static. In some 3D
engines I found they often cache local to base transformations, with
mark dirty scheme.
Banlu
--
.----. Banlu Kemiyatorn
/.../\...\ 漫画家
|.../ \...| http://qstx.blogspot.com (Free Software Advocacy & Development)
|../ \..| http://feedbat.blogspot.com (Studio Work For Hire)
\/ \/ http://groundzerostudiocomplex.blogspot.com (Studio Research)
- Can we have convertTo/FromBase in view?, Banlu Kemiyatorn, 2010/12/21
- Re: Can we have convertTo/FromBase in view?, David Chisnall, 2010/12/21
- Re: Can we have convertTo/FromBase in view?, Fred Kiefer, 2010/12/22
- Re: Can we have convertTo/FromBase in view?, Banlu Kemiyatorn, 2010/12/22
- Re: Can we have convertTo/FromBase in view?, Fred Kiefer, 2010/12/23
- Re: Can we have convertTo/FromBase in view?, Banlu Kemiyatorn, 2010/12/23
- Re: Can we have convertTo/FromBase in view?, Quentin Mathé, 2010/12/25
- Re: Can we have convertTo/FromBase in view?, Quentin Mathé, 2010/12/25
- Re: Can we have convertTo/FromBase in view?,
Banlu Kemiyatorn <=
- Re: Can we have convertTo/FromBase in view?, Banlu Kemiyatorn, 2010/12/25
- Re: Can we have convertTo/FromBase in view?, Quentin Mathé, 2010/12/25