From 4d8de9164cf634c13fe9aecd0945d0e13ee8e23e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luiz=20Am=C3=A9rico?= <luizamericop@gmail.com>
Date: Fri, 15 Nov 2019 22:56:10 -0300
Subject: [PATCH] Fix gradient with multiple stops (#1045)

---
 lib/gradient.js             |  9 +++--
 tests/unit/gradient.spec.js | 76 +++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 4 deletions(-)
 create mode 100644 tests/unit/gradient.spec.js

diff --git a/lib/gradient.js b/lib/gradient.js
index f499f36..8f81e34 100644
--- a/lib/gradient.js
+++ b/lib/gradient.js
@@ -46,14 +46,15 @@ class PDFGradient {
 
   embed(m) {
     let fn;
-    if (this.stops.length === 0) {
+    const stopsLength = this.stops.length;
+    if (stopsLength === 0) {
       return;
     }
     this.embedded = true;
     this.matrix = m;
 
     // if the last stop comes before 100%, add a copy at 100%
-    const last = this.stops[this.stops.length - 1];
+    const last = this.stops[stopsLength - 1];
     if (last[0] < 1) {
       this.stops.push([1, last[1], last[2]]);
     }
@@ -62,7 +63,7 @@ class PDFGradient {
     const encode = [];
     const stops = [];
 
-    for (let i = 0, stopsLength = this.stops.length - 1; i < stopsLength; i++) {
+    for (let i = 0; i < stopsLength - 1; i++) {
       encode.push(0, 1);
       if (i + 2 !== stopsLength) {
         bounds.push(this.stops[i + 1][0]);
@@ -81,7 +82,7 @@ class PDFGradient {
     }
 
     // if there are only two stops, we don't need a stitching function
-    if (stops.length === 1) {
+    if (stopsLength === 1) {
       fn = stops[0];
     } else {
       fn = this.doc.ref({
diff --git a/tests/unit/gradient.spec.js b/tests/unit/gradient.spec.js
new file mode 100644
index 0000000..79f528e
--- /dev/null
+++ b/tests/unit/gradient.spec.js
@@ -0,0 +1,76 @@
+import PDFDocument from '../../lib/document';
+import { logData } from './helpers';
+
+describe('Gradient', function() {
+  let document;
+
+  beforeEach(() => {
+    document = new PDFDocument({
+      info: { CreationDate: new Date(Date.UTC(2018, 1, 1)) }
+    });
+  });
+
+  test('Multiple stops', () => {
+    const docData = logData(document);
+    const gradient = document.linearGradient(0, 0, 300, 0);
+    gradient
+      .stop(0, 'green')
+      .stop(0.5, 'red')
+      .stop(1, 'green');
+    document.rect(0, 0, 300, 300).fill(gradient);
+    document.end();
+
+    expect(docData).toContainChunk([
+      '8 0 obj',
+      `<<
+/FunctionType 2
+/Domain [0 1]
+/C0 [0 0.501961 0]
+/C1 [1 0 0]
+/N 1
+>>`
+    ]);
+    expect(docData).toContainChunk([
+      '9 0 obj',
+      `<<
+/FunctionType 2
+/Domain [0 1]
+/C0 [1 0 0]
+/C1 [0 0.501961 0]
+/N 1
+>>`
+    ]);
+
+    expect(docData).toContainChunk([
+      '10 0 obj',
+      `<<
+/FunctionType 3
+/Domain [0 1]
+/Functions [8 0 R 9 0 R]
+/Bounds [0.5]
+/Encode [0 1 0 1]
+>>`
+    ]);
+
+    expect(docData).toContainChunk([
+      '11 0 obj',
+      `<<
+/ShadingType 2
+/ColorSpace /DeviceRGB
+/Coords [0 0 300 0]
+/Function 10 0 R
+/Extend [true true]
+>>`
+    ]);
+
+    expect(docData).toContainChunk([
+      '12 0 obj',
+      `<<
+/Type /Pattern
+/PatternType 2
+/Shading 11 0 R
+/Matrix [1 0 0 -1 0 792]
+>>`
+    ]);
+  });
+});