Re: [Gegl-developer] new GEGL samplers: what they are and where they are going

[Daniel Rogers]

On Sep 17, 2009, at 6:51 PM, Nicolas Robidoux wrote:


But I am wondering if for GEGL's target user base an always pretty
good default is preferable to choose your poison.


Well, if all GEGL ever has is a always pretty good default and you  
never get to pick your poison, you are making your decision for your  
users.  And frankly, always pretty good is not as cut and dry and  
you'd like to think, off the top of my head here are some image  
processing applications I can think of that have dramatically  
different requirements in a resize operation (I speak from experience  
here, I've been involved with most of the items on this list):


High throughput print on demand rendering services.  (Think  
snapfish.com and their ilk.)

medical research.  (MRI, CT, PET, ultrasound scanners)
astrophysics research.
general physics experimentation (anyone using a camera for measurements)
embedded systems (printers, kiosks, etc)
real time video processing

And of course applications like The GIMP.

All of these require different tradeoffs for their resamplers.  I've  
seen downsamplers that preserve bluriness so you can show a thumbnail  
that is representative of the bluriness you see in a printed product.   
Rescaling text, it's often important to worry less about aliasing and  
more about blur.  Nearest neighbor is actually a perfect resize  
operation for a large class of artificial images.  Medical scientists  
are much more worried about introducing artifacts that could be  
misinterpreted as disease, or potentially blurring away evidence of  
such.  Anyone using a camera for measurements is (depending on the  
measurement) often more interested in geometric stability, regardless  
of blur or aliasing.  Real time video is often about speed.


I think a better question is to ask, are you going to limit GEGL to  
being used solely by The GIMP, and then, only the subset of GIMP users  
you think exist, or are you going to allow your users to create the  
facilities to use GEGL is applications you did not originally envision.


For me the obvious choice is the latter.  Making GEGL suitable for as  
broad a range of applications as possible gets you a larger user base  
and, if done right, higher quality code.  The Linux kernel is a great  
example of this.


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Re: [Gegl-developer] Re: DAGs make users' eyes cross

[Daniel Rogers]

On Tue, 2006-10-17 at 17:31 +, Ken Bateman wrote:
 However, I argue that the spreadsheet model is mentally accessible to a much
 larger user base, and it does not reduce or limit the sophistication of the
 underlying image core DAG.  Spreadsheets provide an easy learning curve and an
 obvious data model.  I have met many people who lack technical sophistication
 that can still create and use spreadsheets.

Please provide specific examples as to how one would represent image
processing operations in a spreadsheet model.  Not something abstract,
but something concrete.  Posit a workflow and represent that workflow as
a spreadsheet.  It doesn't have to be code (though that would be nice)
but it does have to be clear and unambiguous.  Also please explain the
statement that image processing operations naturally fit into arrays.

I'd also point out that LabView (another product that uses a graphical
DAG to do operations) is so easy to use that Lego thinks 10 year old can
do it (check out Lego Mindstorms NXT).  Last I checked no one is
adopting the speadsheet model to make things easier for people.

-- 
Daniel

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