[Color conversion] Add expressions for calculating luminance. (#700)

Added expressions for calculating the luminance of colors according to WCAG 2.0 standards.  (Thanks @Ahnaf30e!)

Author: Ahnaf30e

extensions/reviewed/ColorConversion.json

@@ -7,9 +7,9 @@
   "iconUrl": "data:image/svg+xml;base64,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",
   "name": "ColorConversion",
   "previewIconUrl": "https://resources.gdevelop-app.com/assets/Icons/invert-colors.svg",
-  "shortDescription": "Expressions to convert color values between various formats (RGB, HSV, HSL, named colors) and get colors between 2 others.",
-  "version": "1.2.1",
-  "description": "Expressions to convert color values between various formats (RGB, HSV, HSL, named colors) and get colors between 2 others.",
+  "shortDescription": "Expressions to convert color values between various formats (RGB, HSV, HSL, named colors), calculate luminance according to WCAG 2.0 standards, and to blend two colors.",
+  "version": "1.3.1",
+  "description": "Expressions to convert color values between various formats (RGB, HSV, HSL, named colors), calculate luminance according to WCAG 2.0 standards, and to blend two colors.",
   "origin": {
     "identifier": "ColorConversion",
     "name": "gdevelop-extension-store"
@@ -21,12 +21,16 @@
     "rgb",
     "hsl",
     "hsv",
-    "hsb"
+    "hsb",
+    "luminance",
+    "wcag",
+    "blend"
   ],
   "authorIds": [
     "gqDaZjCfevOOxBYkK6zlhtZnXCg1",
     "AlZ3D1xkH0QDao7T37VZZUeYNpn1",
-    "IWykYNRvhCZBN3vEgKEbBPOR3Oc2"
+    "IWykYNRvhCZBN3vEgKEbBPOR3Oc2",
+    "onPsboRtDkUHNOsx7OPr8R8G1oj2"
   ],
   "dependencies": [],
   "eventsFunctions": [
@@ -81,8 +85,82 @@
       "objectGroups": []
     },
     {
-      "description": "Apply a weighted mean between 2 RGB colors.",
-      "fullName": "RGB mean",
+      "description": "Calculate luminance of a RGB color.  Example input: \"0;128;255\".",
+      "fullName": "Luminance from RGB",
+      "functionType": "Expression",
+      "name": "RgbToLuminance",
+      "sentence": "",
+      "events": [
+        {
+          "type": "BuiltinCommonInstructions::JsCode",
+          "inlineCode": [
+            "function toLuminance(color) {",
+            "    // Convert the color string to an array of RGB values",
+            "    let [r, g, b] = color.split(\";\");",
+            "    let luminance = 0.2126 * r + 0.7152 * g + 0.0722 * b;",
+            "    return luminance;",
+            "}",
+            "",
+            "const color = eventsFunctionContext.getArgument(\"color\");",
+            "eventsFunctionContext.returnValue = toLuminance(color);"
+          ],
+          "parameterObjects": "",
+          "useStrict": true,
+          "eventsSheetExpanded": false
+        }
+      ],
+      "expressionType": {
+        "type": "expression"
+      },
+      "parameters": [
+        {
+          "description": "RGB color",
+          "name": "color",
+          "type": "color"
+        }
+      ],
+      "objectGroups": []
+    },
+    {
+      "description": "Calculate luminance of a hexadecimal color.  Example input: \"0459AF\".",
+      "fullName": "Luminance from hexadecimal",
+      "functionType": "Expression",
+      "name": "HexToLuminance",
+      "sentence": "",
+      "events": [
+        {
+          "type": "BuiltinCommonInstructions::JsCode",
+          "inlineCode": [
+            "function hexToLuminance(color) {",
+            "    // Convert the color string to an array of RGB values",
+            "    let [r, g, b] = color.slice(1).match(/.{2}/g).map(x => parseInt(x, 16));",
+            "    let luminance = 0.2126 * r + 0.7152 * g + 0.0722 * b;",
+            "    return luminance;",
+            "}",
+            "",
+            "const color = eventsFunctionContext.getArgument(\"color\");",
+            "eventsFunctionContext.returnValue = hexToLuminance(color);"
+          ],
+          "parameterObjects": "",
+          "useStrict": true,
+          "eventsSheetExpanded": true
+        }
+      ],
+      "expressionType": {
+        "type": "expression"
+      },
+      "parameters": [
+        {
+          "description": "Hex value",
+          "name": "color",
+          "type": "string"
+        }
+      ],
+      "objectGroups": []
+    },
+    {
+      "description": "Blend two RGB colors by applying a weighted mean.",
+      "fullName": "Blend RGB colors",
       "functionType": "StringExpression",
       "name": "RgbMean",
       "sentence": "",
@@ -134,7 +212,7 @@
         },
         {
           "description": "Ratio",
-          "longDescription": "0 gives the first color, 1 gives the second color",
+          "longDescription": "Range: 0 to 1, where 0 gives the first color and 1 gives the second color",
           "name": "Ratio",
           "type": "expression"
         }