From abdda0afabf9c49b7acd7a6d1f8a5e025a2d4a74 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?F=C3=BCl=C3=B6p=20Kov=C3=A1cs?= <kovacs.fulop@gmail.com>
Date: Tue, 7 Jun 2022 16:05:45 +0200
Subject: [PATCH] Support the three/four/six-value syntax variants of
 <hex-color>

---
 theatre/shared/src/utils/color.ts             | 52 ++++++++++++++++---
 .../simpleEditors/RgbaPropEditor.tsx          |  5 +-
 2 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/theatre/shared/src/utils/color.ts b/theatre/shared/src/utils/color.ts
index 93a022c..655a648 100644
--- a/theatre/shared/src/utils/color.ts
+++ b/theatre/shared/src/utils/color.ts
@@ -1,10 +1,29 @@
 import {clamp} from 'lodash-es'
 
+/**
+ * Robust check for a valid hex value (without the "#") in a string
+ *
+ * @remarks
+ *
+ * Supports all the syntax variants of <hex-color>
+ * {@link https://google.com}:
+ *
+ *
+ * ```javascript
+ * #RGB        // The three-value syntax
+ * #RGBA       // The four-value syntax
+ * #RRGGBB     // The six-value syntax
+ * #RRGGBBAA   // The eight-value syntax
+ * ```
+ */
+export const validHexRegExp = /^#*([0-9a-f]{3,4}|[0-9a-f]{6}|[0-9a-f]{8})$/i
+
 export function parseRgbaFromHex(rgba: string) {
   rgba = rgba.trim().toLowerCase()
-  const hex = rgba.match(/^#?([0-9a-f]{8})$/i)
 
-  if (!hex) {
+  const match = rgba.match(validHexRegExp)
+
+  if (!match) {
     return {
       r: 0,
       g: 0,
@@ -13,12 +32,13 @@ export function parseRgbaFromHex(rgba: string) {
     }
   }
 
-  const match = hex[1]
+  const hex = _hexInEightValueSyntax(match[1])
+
   return {
-    r: parseInt(match.substr(0, 2), 16) / 255,
-    g: parseInt(match.substr(2, 2), 16) / 255,
-    b: parseInt(match.substr(4, 2), 16) / 255,
-    a: parseInt(match.substr(6, 2), 16) / 255,
+    r: parseInt(hex.substr(0, 2), 16) / 255,
+    g: parseInt(hex.substr(2, 2), 16) / 255,
+    b: parseInt(hex.substr(4, 2), 16) / 255,
+    a: parseInt(hex.substr(6, 2), 16) / 255,
   }
 }
 
@@ -126,3 +146,21 @@ export type Laba = {
   b: number
   alpha: number
 }
+
+/**
+ * Returns a hex string in the eight-value syntax
+ */
+function _hexInEightValueSyntax(hex: string): string {
+  switch (hex.length) {
+    case 3:
+      return `${hex.repeat(2)}ff`
+    case 4:
+      const rgb = hex.substr(0, 3)
+      const alpha = hex[3]
+      return `${rgb.repeat(2)}${alpha.repeat(2)}`
+    case 6:
+      return `${hex}ff`
+  }
+
+  return hex
+}
diff --git a/theatre/studio/src/propEditors/simpleEditors/RgbaPropEditor.tsx b/theatre/studio/src/propEditors/simpleEditors/RgbaPropEditor.tsx
index 67b879e..424ffb6 100644
--- a/theatre/studio/src/propEditors/simpleEditors/RgbaPropEditor.tsx
+++ b/theatre/studio/src/propEditors/simpleEditors/RgbaPropEditor.tsx
@@ -1,5 +1,6 @@
 import type {PropTypeConfig_Rgba} from '@theatre/core/propTypes'
-import type {Rgba} from '@theatre/shared/utils/color'
+import type {Rgba} from '@theatre/shared/utils/color';
+import { validHexRegExp} from '@theatre/shared/utils/color'
 import {
   decorateRgba,
   rgba2hex,
@@ -114,7 +115,7 @@ function RgbaPropEditor({
           temporarilySetValue={noop}
           discardTemporaryValue={noop}
           permanentlySetValue={onChange}
-          isValid={(v) => !!v.match(/^#?([0-9a-f]{8})$/i)}
+          isValid={(v) => !!v.match(validHexRegExp)}
         />
       </RowContainer>
       {popoverNode}