"Create selection" is extremely slow on a mac

[Thomas Julou]

Hello,

While trying to run  on my mac a script written on a unix machine, I realised that the Create Selection command applied to a thresholded image was extremely slow. I tried to benchmark it with the code below, unfortunately it looks like the delay is due to refreshing the gui since the time reported is similar on both machine (≈70ms, even with an intermediate updateDisplay()).

Is it possible that displaying a complex selection on a mac is terribly slow (for my images of interest, 7-10s for a 300x400 image with 50% randomly added to the selection)?
Or can it be a problem with Create Selection itself?

> newImage("Untitled", "32-bit black", 400, 300, 1);
> run("Add Noise");
> setAutoThreshold("Default dark");
> t_start = getTime();
> run("Create Selection");
> // updateDisplay()
> dt = getTime() - t_start;
> print(dt);

Using IJ 2.0.0-rc-34/1.50a with Java 1.7.0_79.
Thank you in advance for you help. Best regards,

Thomas

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Thomas Julou  |  Computational & Systems Biology  |  Biozentrum – University of Basel  |  Klingelbergstrasse 50/70 CH-4056 Basel  |  [phone]

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[Rasband, Wayne (NIH/NIMH) [E]]

> On Aug 19, 2015, at 11:54 AM, Thomas Julou <[hidden email]> wrote:
>
> Hello,
>
> While trying to run  on my mac a script written on a unix machine, I realised that the Create Selection command applied to a thresholded image was extremely slow. I tried to benchmark it with the code below, unfortunately it looks like the delay is due to refreshing the gui since the time reported is similar on both machine (≈70ms, even with an intermediate updateDisplay()).
>
> Is it possible that displaying a complex selection on a mac is terribly slow (for my images of interest, 7-10s for a 300x400 image with 50% randomly added to the selection)?
> Or can it be a problem with Create Selection itself?
>
>> newImage("Untitled", "32-bit black", 400, 300, 1);
>> run("Add Noise");
>> setAutoThreshold("Default dark");
>> t_start = getTime();
>> run("Create Selection");
>> // updateDisplay()
>> dt = getTime() - t_start;
>> print(dt);
>
> Using IJ 2.0.0-rc-34/1.50a with Java 1.7.0_79.
> Thank you in advance for you help. Best regards,

On OS X, Java 7 and Java 8, prior to 1.8.0_45, are extremely slow at displaying images. You need to either upgrade to the latest version of Java 8 (1.8.0_51) or revert to Java 6.

-wayne


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