update the contrast rule to include CJK #1735

IBMa · Mar 29, 2024 · 91e7479 · 91e7479
1 parent b068b7a
commit 91e7479
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Showing 2 changed files with 28 additions and 3 deletions.
diff --git a/accessibility-checker-engine/src/v4/rules/text_contrast_sufficient.ts b/accessibility-checker-engine/src/v4/rules/text_contrast_sufficient.ts
@@ -17,7 +17,8 @@ import { ColorUtil } from "../../v2/dom/ColorUtil";
 import { Rule, RuleResult, RuleFail, RuleContext, RulePotential, RulePass, RuleContextHierarchy } from "../api/IRule";
 import { eRulePolicy, eToolkitLevel } from "../api/IRule";
 //import { setCache } from "../util/CacheUtil";
-import { getWeightNumber, getFontInPixels } from "../util/CSSUtil";
+import { getWeightNumber, getFontInPixels} from "../util/CSSUtil";
+import { containsCKJ } from "../util/CommonUtil";
 
 export let text_contrast_sufficient: Rule = {
     id: "text_contrast_sufficient",
@@ -105,8 +106,8 @@ export let text_contrast_sufficient: Rule = {
              * (3) for now not consider unicode special characters that are different in different languages
             */
             let regex = /[^(a-zA-Z\d\s)\u0000-\u0008\u000B-\u001F\u007F-\u009F\u2000-\u200F\u2028-\u202F\u205F-\u206F\u3000\uFEFF]+/g;
-            const removed = childStr.trim().replace(regex, '');
-            if (removed.trim().length === 0)
+            childStr = childStr.trim().replace(regex, '');
+            if (childStr.trim().length === 0)
                 return null;
         }
 
@@ -252,6 +253,11 @@ export let text_contrast_sufficient: Rule = {
         let weight = getWeightNumber(style.fontWeight);
         let size = getFontInPixels(style.fontSize, elem);
         let isLargeScale = size >= 24 || size >= 18.6 && weight >= 700;
+
+        if (containsCKJ(childStr)) {
+            // for CJK, 22 pt or 18 pt with font-weight >= 700, 1pt = 1.333 px
+            isLargeScale = size >= 29.3 || size >= 24 && weight >= 700;
+        }    
         let passed = ratio >= 4.5 || (ratio >= 3 && isLargeScale);
         let hasBackground = colorCombo.hasBGImage || colorCombo.hasGradient;
         let textShadow = colorCombo.textShadow;

diff --git a/accessibility-checker-engine/src/v4/util/CommonUtil.ts b/accessibility-checker-engine/src/v4/util/CommonUtil.ts
@@ -219,3 +219,22 @@ export function getDeprecatedAriaAttributes(element: Element) {
     }
     return ret; 
 }
+
+/* 
+ * string contains CJK (chinese, japaneses, or korea)
+ * return: boolean
+*/
+export function containsCKJ(text: string) {
+    if (!text) return false;
+
+    // https://en.wikipedia.org/wiki/CJK_Unified_Ideographs
+    let regex = /[\u4E00-\u9FFF]+/g;
+    //[\u4e00-\u9fff\u3400-\u4dbf\ufa0e\ufa0f\ufa11\ufa13\ufa14\ufa1f\ufa21\ufa23\ufa24\ufa27\ufa28\ufa29\u3006\u3007]|[\ud840-\ud868\ud86a-\ud879\ud880-\ud887][\udc00-\udfff]|\ud869[\udc00-\udedf\udf00-\udfff]|\ud87a[\udc00-\udfef]|\ud888[\udc00-\udfaf])([\ufe00-\ufe0f]|\udb40[\udd00-\uddef]
+    //[\u4e00-\u9fff\u3400-\u4dbf\u{20000}-\u{2a6df}\u{2a700}-\u{2ebef}\u{30000}-\u{323af}\ufa0e\ufa0f\ufa11\ufa13\ufa14\ufa1f\ufa21\ufa23\ufa24\ufa27\ufa28\ufa29\u3006\u3007][\ufe00-\ufe0f\u{e0100}-\u{e01ef}]?
+
+    const replaced = text.trim().replace(regex, '');
+    if (replaced.length === text.trim().length)
+        return false;
+
+    return true;
+}