Editor: color properties are clamping RGB values inconsistenly with the engine

[ivan-mogilko]

Problem

Because in AGS color index <-> RGB mapping is done based on 16-bit RGB values, both Editor and Engine fixup any assigned RGB value by clamping its components to R5G6B5 format (i think). (On a side note, there's a task to remove this clamping in ags4, see #1980)

However, it seems that Editor's mapping is different from the Engine's.
Sometimes the RGB value typed into a property field is clamped to one result, but using Game.GetColorFromRGB in script produces a different result.

For example:
Input value: 167, 181, 147
Editor clamps to: 160, 180, 144
Engine clamps to: 165, 182, 148

UPDATE: user reports there's another inconsistency, when using Colours Pane for making color numbers and then trying to insert them into the color number properties. Following is user's explanation:

I plugged in 73, 106, 69 into the colour selector in the colour panel
it spat out a decimal number
I plugged in that number into the speechview colour
it reclamped it to 72, 104, 64
but if I go to the Colour Panel and tap the FIND COLOUR next to the generated number of 19272
it shows 73, 106, 69

AGS Version

Any 3.* version, I think.

Expected behavior

I believe that the Editor should comply to the engine's formula when clamping colors.