diff --git a/testing/resources/pixel/bug_1639_1.in b/testing/resources/pixel/bug_1639_1.in
new file mode 100644
index 0000000..f283af7
--- /dev/null
+++ b/testing/resources/pixel/bug_1639_1.in
@@ -0,0 +1,50 @@
+{{header}}
+{{object 1 0}} <<
+  /Type /Catalog
+  /Pages 2 0 R
+>>
+endobj
+{{object 2 0}} <<
+  /Type /Pages
+  /Count 1
+  /Kids [3 0 R]
+>>
+endobj
+{{object 3 0}} <<
+  /Type /Page
+  /Parent 2 0 R
+  /Contents 4 0 R
+  /MediaBox [0 0 200 200]
+  /Resources <<
+    /ExtGState <<
+      /GS1 <<
+        /ca 1.0
+      >>
+    >>
+  >>
+>>
+endobj
+{{object 4 0}} <<
+  {{streamlen}}
+>>
+stream
+q
+/GS1 gs
+0 0 1 rg
+% A horizontal path.
+20 180 m
+180 180 l
+% A vertical path.
+50 160 m
+50 100 l
+% A diagonal path.
+20 50 m
+180 100 l
+f
+Q
+endstream
+endobj
+{{xref}}
+{{trailer}}
+{{startxref}}
+%%EOF
diff --git a/testing/resources/pixel/bug_1639_1_expected.pdf.0.png b/testing/resources/pixel/bug_1639_1_expected.pdf.0.png
new file mode 100644
index 0000000..f97e340
--- /dev/null
+++ b/testing/resources/pixel/bug_1639_1_expected.pdf.0.png
Binary files differ