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#153 Inconsistent attribute "Fill intensity %"
I think that the attribute "Fill intensity %" does not present a logical/consistent behaviour:
- A figure with "Fill color=Black" and "Fill style=Filled", with "Fill intensity %=5" shows a very light grey. For me this is the expected behaviour.
- A figure with "Fill color=White" and "Fill style=Filled", with "Fill intensity %=5" shows almost black. For me this is NOT the expected behaviour. I would expect a white fill colour, independently of the fill intensity.
- A figure with "Fill color=Red" and "Fill style=Filled", with "Fill intensity %=5" shows almost black. For me this is NOT the expected behaviour. I would expect a very light red.
Unfortunately, color nomenclature is not a straightforward subject, and easily debatable. Furthermore, xfig refers with "Fill intensity" to both shades and tints of a color, viz., values of intensity between 0 and 100 are shades and between 100 and 200 tints. This is part of the problem.The conversion to tint percentage would be tint = intensity -100, the conversion to shade would read: shade = 100 - intensity. What you propose above is the behaviour of a tint, but reversed: tint = 0 ... white, tint = 100 ... original color.
Since, I am afraid, conventions of color definitions are not overly strict or well known, I do not see a strong argument to change the current behaviour. I myself always have to think for a moment whether a rgb-triplet of 0,0,0 refers to black or white. It turns out, it is black, consistent with xfig Fill intensity. Also, when a fill intensity is chosen in the bottom ruler, the result of the mix is shown. For lack of better and widely understood nomenclature, I would prefer to keep the current designation and behaviour.