Set transparency attenuation to %45 + 2%/m.

common/colors.go

@@ -115,8 +115,8 @@ func (colors *Colors) BlendColors(span *Span, col color.RGBA, pos int32) color.R
 	}
 	const scale = float32(1) / float32(100)
 	for ; curr != nil; curr = curr.Next {
-		// At least 35% attenuation + 5% extra for each depth meter.
-		factor := float32(min(100, 35+(curr.To-curr.From)*5)) * scale
+		// At least 45% attenuation + 2% extra for each depth meter.
+		factor := float32(min(100, 45+(curr.To-curr.From)*2)) * scale
 		col = BlendColor(colors.Colors[curr.Value], col, factor)
 	}
 	return col