comments, test and changelog entry for fix when a character is too bigger than the width of the text.

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## pdfkit changelog
 
 ### Unreleased
+ - Fix infinite loop when an individual character is bigger than the width of the text.
  - Fix infinite loop when text is positioned after page right margin
  - Allow links in continued text to be stopped by setting link to null
 

lib/line_wrapper.js

@@ -123,6 +123,7 @@ class LineWrapper extends EventEmitter {
             }
           }
 
+          // check for the edge case where a single character cannot fit into a line.
           if (l === 0 && this.spaceLeft === this.lineWidth) {
             l = 1;
           }

tests/unit/text.spec.js

@@ -15,7 +15,7 @@ describe('Text', () => {
     test('with simple content', () => {
       const docData = logData(document);
 
-      const textStream = new Buffer(
+      const textStream = Buffer.from(
         `1 0 0 -1 0 792 cm
 q
 1 0 0 -1 0 792 cm
@@ -47,7 +47,7 @@ Q
     test('with content ending after page right margin', () => {
       const docData = logData(document);
 
-      const textStream = new Buffer(
+      const textStream = Buffer.from(
         `1 0 0 -1 0 792 cm
 q
 1 0 0 -1 0 792 cm
@@ -68,6 +68,125 @@ Q
         `5 0 obj`,
         `<<
 /Length 117
+>>`,
+        `stream`,
+        textStream,
+        `\nendstream`,
+        `endobj`
+      ]);
+    });
+
+    test('with line too thin to contain a single character', () => {
+      const docData = logData(document);
+
+      const text = 'simple text';
+      const textStream = Buffer.from(
+        `1 0 0 -1 0 792 cm
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 773.384 Tm
+/F1 12 Tf
+[<73> 0] TJ
+ET
+Q
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 759.512 Tm
+/F1 12 Tf
+[<69> 0] TJ
+ET
+Q
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 745.64 Tm
+/F1 12 Tf
+[<6d> 0] TJ
+ET
+Q
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 731.768 Tm
+/F1 12 Tf
+[<70> 0] TJ
+ET
+Q
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 717.896 Tm
+/F1 12 Tf
+[<6c> 0] TJ
+ET
+Q
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 704.024 Tm
+/F1 12 Tf
+[<65> 0] TJ
+ET
+Q
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 690.152 Tm
+/F1 12 Tf
+[<2074> 0] TJ
+ET
+Q
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 676.28 Tm
+/F1 12 Tf
+[<65> 0] TJ
+ET
+Q
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 662.408 Tm
+/F1 12 Tf
+[<78> 0] TJ
+ET
+Q
+q
+1 0 0 -1 0 792 cm
+BT
+1 0 0 1 10 648.536 Tm
+/F1 12 Tf
+[<74> 0] TJ
+ET
+Q
+`,
+        'binary'
+      );
+
+      // before this test, this case used to make the code run into an infinite loop.
+      // To handle regresion gracefully and avoid stucking this test into an infinite loop,
+      // we look out for a side effect of this infinite loop, witch is adding and infinite number of pages.
+      // Nomaly, there should not be any page added to the document.
+
+      document.on("pageAdded", () => {
+		const pageRange = document.bufferedPageRange();
+		const newPageIndex = pageRange.start + pageRange.count;
+        // We try restrict the fail condition to only infinite loop, so we wait for several pages to be added.
+        if (newPageIndex > 10) {
+          throw new Error("Infinite loop detected");
+        }
+      });
+
+      document.text(text, 10, 10, {width: 2});
+      document.end();
+
+      expect(docData).toContainChunk([
+        `5 0 obj`,
+        `<<
+/Length 738
 >>`,
         `stream`,
         textStream,