Apca UI parameters (#169)

* added tests and updated getContrast function for APCA support

* feat: added parameter support (URL) for formula

packages/ui/src/js/params.js

@@ -52,6 +52,14 @@ function paramSetup() {
     let baseScale = config.baseScale;
     let lightness = (config.lightness) ? config.lightness : config.brightness;
     let contrast;
+    let formula;
+    if(!config.formula) {
+      formula = 'wcag2'
+    } else {
+      formula = config.formula
+    }
+    _theme.formula = formula;
+
     if(!config.contrast) {
       contrast = 1;
     } else {
@@ -114,6 +122,10 @@ function paramSetup() {
       addRatioInputs(values[0], values[1])
     }).then(() => {
       setTimeout(() => {
+        document.getElementById('themeWCAG').value = formula;
+        let label = document.getElementById('ratioInputLabel')
+        label.innerHTML = (formula === 'wcag2') ? 'WCAG 2 contrast' : ((formula === 'wcag3') ? 'APCA contrast': 'Contrast');
+
         sortRatios();
       }, 500)
     });

packages/ui/src/theme.js

@@ -139,6 +139,7 @@ import {sortColorScales} from './js/sortColorScales';
 import {
   togglePopover
 } from './js/popover';
+import { forceSimulation } from 'd3';
 
 const { readFileSync } = require('fs')
 const posthtml = require('posthtml')
@@ -166,7 +167,8 @@ function updateParams() {
     }),
     lightness: _theme.lightness,
     contrast: _theme.contrast,
-    saturation: _theme.saturation
+    saturation: _theme.saturation,
+    formula: _theme.formula
   };
   let url = new URL(window.location);
   let params = new URLSearchParams(url.search.slice(1));