From 5b5dfbad776a2d1aba0739eb52f23b7996821682 Mon Sep 17 00:00:00 2001
From: Lovell Fuller <github@lovell.info>
Date: Wed, 9 Apr 2025 22:21:14 +0100
Subject: [PATCH] Ensure pdfBackground constructor property is used #4207

Slightly refactor the way background colours are set
---
 docs/src/content/docs/changelog.md |  5 +++++
 lib/colour.js                      | 33 ++++++++++++++++++++----------
 lib/input.js                       | 19 +++--------------
 lib/operation.js                   |  9 +-------
 4 files changed, 31 insertions(+), 35 deletions(-)

diff --git a/docs/src/content/docs/changelog.md b/docs/src/content/docs/changelog.md
index 559c5e36..81a4ec1d 100644
--- a/docs/src/content/docs/changelog.md
+++ b/docs/src/content/docs/changelog.md
@@ -6,6 +6,11 @@ title: Changelog
 
 Requires libvips v8.16.1
 
+### v0.34.2 - TBD
+
+* Ensure `pdfBackground` constructor property is used.
+  [#4207](https://github.com/lovell/sharp/pull/4207)
+
 ### v0.34.1 - 7th April 2025
 
 * TypeScript: Ensure new `autoOrient` property is optional.
diff --git a/lib/colour.js b/lib/colour.js
index d8a4de4f..ad283830 100644
--- a/lib/colour.js
+++ b/lib/colour.js
@@ -134,6 +134,26 @@ function toColorspace (colorspace) {
   return this.toColourspace(colorspace);
 }
 
+/**
+ * Create a RGBA colour array from a given value.
+ * @private
+ * @param {string|Object} value
+ * @throws {Error} Invalid value
+ */
+function _getBackgroundColourOption (value) {
+  if (is.object(value) || is.string(value)) {
+    const colour = color(value);
+    return [
+      colour.red(),
+      colour.green(),
+      colour.blue(),
+      Math.round(colour.alpha() * 255)
+    ];
+  } else {
+    throw is.invalidParameterError('background', 'object or string', value);
+  }
+}
+
 /**
  * Update a colour attribute of the this.options Object.
  * @private
@@ -143,17 +163,7 @@ function toColorspace (colorspace) {
  */
 function _setBackgroundColourOption (key, value) {
   if (is.defined(value)) {
-    if (is.object(value) || is.string(value)) {
-      const colour = color(value);
-      this.options[key] = [
-        colour.red(),
-        colour.green(),
-        colour.blue(),
-        Math.round(colour.alpha() * 255)
-      ];
-    } else {
-      throw is.invalidParameterError('background', 'object or string', value);
-    }
+    this.options[key] = _getBackgroundColourOption(value);
   }
 }
 
@@ -173,6 +183,7 @@ module.exports = function (Sharp) {
     toColourspace,
     toColorspace,
     // Private
+    _getBackgroundColourOption,
     _setBackgroundColourOption
   });
   // Class attributes
diff --git a/lib/input.js b/lib/input.js
index 4ef9f94d..d9d29f3a 100644
--- a/lib/input.js
+++ b/lib/input.js
@@ -3,7 +3,6 @@
 
 'use strict';
 
-const color = require('color');
 const is = require('./is');
 const sharp = require('./sharp');
 
@@ -249,7 +248,7 @@ function _createInputDescriptor (input, inputOptions, containerOptions) {
     }
     // PDF background colour
     if (is.defined(inputOptions.pdfBackground)) {
-      this._setBackgroundColourOption('pdfBackground', inputOptions.pdfBackground);
+      inputDescriptor.pdfBackground = this._getBackgroundColourOption(inputOptions.pdfBackground);
     }
     // Create new image
     if (is.defined(inputOptions.create)) {
@@ -288,13 +287,7 @@ function _createInputDescriptor (input, inputOptions, containerOptions) {
           if (!is.inRange(inputOptions.create.channels, 3, 4)) {
             throw is.invalidParameterError('create.channels', 'number between 3 and 4', inputOptions.create.channels);
           }
-          const background = color(inputOptions.create.background);
-          inputDescriptor.createBackground = [
-            background.red(),
-            background.green(),
-            background.blue(),
-            Math.round(background.alpha() * 255)
-          ];
+          inputDescriptor.createBackground = this._getBackgroundColourOption(inputOptions.create.background);
         } else {
           throw new Error('Expected valid noise or background to create a new input image');
         }
@@ -410,13 +403,7 @@ function _createInputDescriptor (input, inputOptions, containerOptions) {
           }
         }
         if (is.defined(inputOptions.join.background)) {
-          const background = color(inputOptions.join.background);
-          inputDescriptor.joinBackground = [
-            background.red(),
-            background.green(),
-            background.blue(),
-            Math.round(background.alpha() * 255)
-          ];
+          inputDescriptor.joinBackground = this._getBackgroundColourOption(inputOptions.join.background);
         }
         if (is.defined(inputOptions.join.halign)) {
           if (is.string(inputOptions.join.halign) && is.string(this.constructor.align[inputOptions.join.halign])) {
diff --git a/lib/operation.js b/lib/operation.js
index d6cbbdf8..f76f65dc 100644
--- a/lib/operation.js
+++ b/lib/operation.js
@@ -3,7 +3,6 @@
 
 'use strict';
 
-const color = require('color');
 const is = require('./is');
 
 /**
@@ -67,13 +66,7 @@ function rotate (angle, options) {
   } else if (is.number(angle)) {
     this.options.rotationAngle = angle;
     if (is.object(options) && options.background) {
-      const backgroundColour = color(options.background);
-      this.options.rotationBackground = [
-        backgroundColour.red(),
-        backgroundColour.green(),
-        backgroundColour.blue(),
-        Math.round(backgroundColour.alpha() * 255)
-      ];
+      this._setBackgroundColourOption('rotationBackground', options.background);
     }
   } else {
     throw is.invalidParameterError('angle', 'numeric', angle);