move ui & assets to package directory

hyperglass/ui/util.js

@@ -0,0 +1,28 @@
+import chroma from "chroma-js";
+
+const isDark = color => {
+    // YIQ equation from http://24ways.org/2010/calculating-color-contrast
+    const rgb = chroma(color).rgb();
+    const yiq = (rgb[0] * 299 + rgb[1] * 587 + rgb[2] * 114) / 1000;
+    return yiq < 128;
+};
+
+const isLight = color => isDark(color);
+
+const opposingColor = (theme, color) => {
+    const opposing = isDark(color) ? theme.colors.white : theme.colors.black;
+    return opposing;
+};
+
+const googleFontUrl = (fontFamily, weights = [300, 400, 700]) => {
+    const urlWeights = weights.join(",");
+    const fontName = fontFamily
+        .split(/, /)[0]
+        .trim()
+        .replace(/'|"/g, "");
+    const urlFont = fontName.split(/ /).join("+");
+    const urlBase = `https://fonts.googleapis.com/css?family=${urlFont}:${urlWeights}&display=swap`;
+    return urlBase;
+};
+
+export { isDark, isLight, opposingColor, googleFontUrl };