src -> app; move core libs to tengri

app/src/view_color.rs

@@ -0,0 +1,22 @@
+use crate::*;
+impl Tek {
+    pub(crate) fn colors (
+        theme:    &ItemPalette,
+        prev:     Option<ItemPalette>,
+        selected: bool,
+        neighbor: bool,
+        is_last:  bool,
+    ) -> [Color;4] {
+        let fg = theme.lightest.rgb;
+        let bg = if selected { theme.light } else { theme.base }.rgb;
+        let hi = Self::color_hi(prev, neighbor);
+        let lo = Self::color_lo(theme, is_last, selected);
+        [fg, bg, hi, lo]
+    }
+    pub(crate) fn color_hi (prev: Option<ItemPalette>, neighbor: bool) -> Color {
+        prev.map(|prev|if neighbor { prev.light.rgb } else { prev.base.rgb }).unwrap_or(Reset)
+    }
+    pub(crate) fn color_lo (theme: &ItemPalette, is_last: bool, selected: bool) -> Color {
+        if is_last { Reset } else if selected { theme.light.rgb } else { theme.base.rgb }
+    }
+}