Pierre Joye skrev:
> On Tue, Jun 10, 2008 at 6:58 PM, ShadowRoze <roze@laun.se> wrote:
> 
>> I load the following types with the script utilizing the function: jpeg,
>> gif, png.
>> Not using ImageColorsForIndex results in having to use bitshifting instead.
> 
> Which is faster than calling the function and access the array table elements.
> 
>> After trying to implement all your suggestions the time required increased
>> with 50% (ergo, to 30s).
> 
> I was not clear or you did something wrong (see below). I'm also not
> sure why you copy the images twice (except if you want to copy it over
> itself), filling it neither.
> 
> If you like to have a specific color (or translucent) for the
> uncovered area, you can use imagefilledrectangle and only with the
> desired area(s). It will also spare you some cycles (flood fill is
> slow).
> 
>> Guess I'll have to wait for that one then.
> 
> Well, as I said, you are missing the main goal of  this algorithm. To
> use bicubic for reducing the size of an image is completely useless
> (be in C, php or whatever else).
> 
> I also wonder why you don't use imagecopyresampled.

Sorry, I checked and notice I used imagecopyresized (for its speed), 
however, I changed to resampled, and still was quite unhappy about the 
speed, even thou it went down to ~2s. But solved it with db-files for cache.

Thanks anyway.

> Now about the possible optimization of your scripts, using only
> truecolor images and the other things I listed earlier:
> 
> (in second)
> ImageCopyResampledBicubic: 1.76
> ImageCopyResampledBicubic2: 21.46
> ImageCopyResampledBicubic: 31.84
> 
> The sources image is 3072x2034 and resized to 550x275.
> 
> Results can be seen here:
> 
> http://pierre.libgd.org/resize/
> 
> I don't see any relevant differences, nothing than can justify a PHP
> implementation.
> 
> I'm pretty sure to drastically reduce these numbers by using a simpler
> algorithm without visible impact.
> 
> If you load a png, verify if the image is truecolor, if not you can
> use your version, if not it is fine to use Bicubic2.
> 
> 
> Cheers,
> --
> Pierre
> 
> http://blog.thepimp.net | http://www.libgd.org