new gegl-sampler code (GSoC): maximum expected downsampling ratio
Forums ► For GEGL developers (read-only) ► new gegl-sampler code (GSoC): maximum expected downsampling ratio
-
Nicolas Robidoux
(over 2 years ago)
- Nicolas Robidoux (over 2 years ago)
Sent: 2009-06-14 19:35:57 UTC (over 2 years ago)
From: Nicolas Robidoux
new gegl-sampler code (GSoC): maximum expected downsampling ratio
In case it turns out to be difficult to set the context_rect to be
variable (set on an output pixel by pixel basis--Eric is looking into
this), I'd like to know what I could assume is the largest reasonable
downsampling ratio, meaning that larger downsampling ratios would be
clamped down to this ceiling. Such clamping would allow us to set the
context rectangle to a (reasonably small) fixed value.More specifically, could I reasonably clamp the downsampling ratio (in
each direction) to one of the following values?1.0 (context_rect.width = 4)
2.7182818284 (context_rect.width = 5)
7.3890560989 (context_rect.width = 6)
20.0855369231 (context_rect.width = 7)
54.5981500331
148.4131591025
403.4287934927
1096.6331584284
2980.9579870417 (context_rect.width = 12)(first and last ones included for the sake of completeness.)
The smaller the maximum, the faster the code will run.
(As the above table makes pretty obvious, the method will be more
suitable for mild downsampling that "heavy duty.")Nicolas Robidoux
Universite Laurentienne_______________________________________________
Gegl-developer mailing list
Gegl-developer@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
Sent: 2009-06-28 20:57:34 UTC (over 2 years ago)
From: Nicolas Robidoux
new gegl-sampler code (GSoC): maximum expected downsampling ratio
Adam Turcotte has communicated to me that he is pretty sure that
context_rect can be changed dynamically. Consequently, this thread is
obsolete (unless changing context_rect dynamically leads to a high
speed penalty), because the largest context_rect for the suggested
method is not so large so as to "stick out" of the fetch_rectangle.Nicolas Robidoux
_______________________________________________
Gegl-developer mailing list
Gegl-developer@lists.XCF.Berkeley.EDU
https://lists.XCF.Berkeley.EDU/mailman/listinfo/gegl-developer
