I want to use a specific palette to make it strictly index color.

[ken]

Additional information:
Indexed color conversion also fails in the recently released GIMP 3.0.0-RC2.
Also, when you select a color in an image with the eyedropper tool, it should select which color in the palette that color will become, but if the color is close to a color you already have (foreground color or background color), the selection may not be successful.

[Ofnuts]

(01-06-2025, 04:02 AM)ken Wrote: Additional information:
Indexed color conversion also fails in the recently released GIMP 3.0.0-RC2.

Should be better though. See https://gitlab.gnome.org/GNOME/gimp/-/issues/12579

(01-06-2025, 04:02 AM)ken Wrote: Also, when you select a color in an image with the eyedropper tool, it should select which color in the palette that color will become, but if the color is close to a color you already have (foreground color or background color), the selection may not be successful.

If the image is indexed, you should get a color which is already in the palette?

[ken]

(01-06-2025, 12:22 PM)Ofnuts Wrote:

(01-06-2025, 04:02 AM)ken Wrote: Additional information:
Indexed color conversion also fails in the recently released GIMP 3.0.0-RC2.

Should be better though. See https://gitlab.gnome.org/GNOME/gimp/-/issues/12579

(01-06-2025, 04:02 AM)ken Wrote: Also, when you select a color in an image with the eyedropper tool, it should select which color in the palette that color will become, but if the color is close to a color you already have (foreground color or background color), the selection may not be successful.

If the image is indexed, you should get a color which is already in the palette?

Thank you for your investigation there as well.
I tested it again here,

and it seems that the presence or absence of the bug depends on the index color conversion method.

Here is a reproduction of the bug.

The process is the same from Image → Mode → Index Color,

but with the color map,

the conversion works fine when I use "Generate optimal palette",

but when I convert using a custom palette, the problem occurs.

There are several conversion errors, but one example of an error is that palette numbers 165 to 168 are strange.

I have attached custom palette data (gpl) in the same order as the image, so please check it out.