32f linear precision, Select by Color, clicking on a red dot picks the orange dots instead
Tested on GIMP-2.99 updated today on Debian Sid and also on Gentoo, but it also happened before updating:
When using the Select by Color tool set to select by LCh hue, in a sample file with a column of red dots (hue=24) and a column of orange dots (hue=53), with Threshold 8.0, using "Replace current selection, at 32f Perceptual precision, when clicking on one of the red dots, all the red dots are selected, as expected.
Changing the precision to linear and clicking on the same red dot, unselects all the red dots and instead selects the orange dots.
Here's the video: simplescreenrecorder-2019-03-04_13.21.17
Here's the file with the dots: samples.tar.gz
Here's the steps to reproduce:
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First go into Preferences and make sure that under Image Import & Export, the option to promote imported images to floating point precision is not checked. Also make sure under "Color profile policy" that "Keep embedded profile" is checked. And on the Color Management page, make sure that under Policies, under File open behavior, that again "Keep embedded profiles" is checked.
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Then restart GIMP. I think changing these policies doesn't take effect until GIMP is restarted.
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Download and unpack samples.tar.gz posted above.
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Open "samples.png", which is at 16-bit integer precision.
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Promote the precision to 32-bit floating point. "Linear light" will be selected by default. Change "Linear light" to "Perceptual gamma (sRGB)".
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Click on the Select by Color tool. Settings should be as follows:
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Click on the bottom red dot (first column of dots). As expected, all the red dots will be selected, and none of the orange dots will be selected.
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Change the precision ("Image/Precision") from "Perceptual gamma (sRGB)" to "Linear light".
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Click on the bottom red dot again. None of the red dots are selected. All of the orange dots are selected.
This is weird. It doesn't happen on 2.10 updated today.