Merge pull request #718 from vector-im/fix-css-compile-variables

Theming - Some more changes for compile-variables plugin

scripts/postcss/color.js

@@ -16,8 +16,17 @@ limitations under the License.
 
 const offColor = require("off-color").offColor;
 
-module.exports.derive = function (value, operation, argument) {
+module.exports.derive = function (value, operation, argument, isDark) {
     const argumentAsNumber = parseInt(argument);
+    if (isDark) {
+        // For dark themes, invert the operation
+        if (operation === 'darker') {
+            operation = "lighter";
+        }
+        else if (operation === 'lighter') {
+            operation = "darker";
+        }
+    }
     switch (operation) {
         case "darker": {
             const newColorString = offColor(value).darken(argumentAsNumber / 100).hex();

scripts/postcss/css-compile-variables.js

@@ -33,6 +33,7 @@ const valueParser = require("postcss-value-parser");
 let aliasMap;
 let resolvedMap;
 let baseVariables;
+let isDark;
 
 function getValueFromAlias(alias) {
     const derivedVariable = aliasMap.get(alias);
@@ -78,7 +79,7 @@ function resolveDerivedVariable(decl, derive) {
             if (!value) {
                 throw new Error(`Cannot derive from ${baseVariable} because it is neither defined in config nor is it an alias!`);
             }
-            const derivedValue = derive(value, operation, argument);
+            const derivedValue = derive(value, operation, argument, isDark);
             resolvedMap.set(wholeVariable, derivedValue);
         }
     }
@@ -123,6 +124,7 @@ function populateMapWithDerivedVariables(map, cssFileLocation) {
  * @param {string} value - The base value on which an operation is applied
  * @param {string} operation - The operation to be applied (eg: darker, lighter...)
  * @param {string} argument - The argument for this operation
+ * @param {boolean} isDark - Indicates whether this theme is dark
  */
 /**
  * 
@@ -134,6 +136,8 @@ module.exports = (opts = {}) => {
     aliasMap = new Map();
     resolvedMap = new Map();
     baseVariables = new Map();
+    isDark = false;
+
     return {
         postcssPlugin: "postcss-compile-variables",
 
@@ -143,6 +147,7 @@ module.exports = (opts = {}) => {
                 // If this is a runtime theme, don't derive variables.
                 return;
             }
+            isDark = cssFileLocation.includes("dark=true");
             /*
             Go through the CSS file once to extract all aliases and base variables.
             We use these when resolving derived variables later.
@@ -153,8 +158,13 @@ module.exports = (opts = {}) => {
             if (opts.compiledVariables){
                 populateMapWithDerivedVariables(opts.compiledVariables, cssFileLocation);
             }
-            // Publish both the base-variables and derived-variables to the other postcss-plugins
+            // Also produce a mapping from alias to completely resolved color
-            const combinedMap = new Map([...baseVariables, ...resolvedMap]);
+            const resolvedAliasMap = new Map();
+            aliasMap.forEach((value, key) => {
+                resolvedAliasMap.set(key, resolvedMap.get(value));
+            });
+            // Publish the base-variables, derived-variables and resolved aliases to the other postcss-plugins
+            const combinedMap = new Map([...baseVariables, ...resolvedMap, ...resolvedAliasMap]);
             result.messages.push({
                 type: "resolved-variable-map",
                 plugin: "postcss-compile-variables",