X-1.0rc2: exact() information is lost in GUI on reopening --- workaround

[anatoly techtonik]

**** workaround:
use similar(0.99) instead
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When a pattern is defined as exact match using 1.0 similarity in GUI, the image gets "1.0" marker and the .py file contains the following source:
  img = Pattern("img.png").exact()

However, if you save and reopen Sikuli, the "1.0" marker is lost, and click on image resets similarity slider to a value of 0.7. This creates big trouble when debugging, because engine still matches the picture as exact() match and if PS doesn't have exact similarity, Matching Preview will show that there is no match until you move slider.

Vista 32.

[RaiMan (raimund-hocke)]

this is a known bug (but cannot find it right now :-(

Using similar(1.0) has some other oddities, so I use 0.99 instead in those cases.

[anatoly techtonik (techtonik)]

I actually thought that exact matching could speed up the process.

[RaiMan (raimund-hocke)]

No, specifying similar(some-value) only sets the value, that is taken internally to decide, wether something was found or not in comparison with the match's score.

So specifying similar(x) with x > 0.9 is always dangerous and only useable if you are sure, that the match's score will be greater than 0.9 in all cases.

specifying 0.99 or 1.0 even makes the search slower (about 25% longer), because internally an additional comparison step takes place.

Specifying similar(x) usually is only needed if you have to assure that a specific image should be found in cases, where otherwise another image with a lower score would be found first.

[anatoly techtonik (techtonik)]

Thanks for the explanation. That really helps to understand Sikuli better.