From bc11b2d6a902bb17e555678b0a0bbba4ba486e98 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Fri, 4 Aug 2023 18:46:58 +1000
Subject: [PATCH] Set SMaskInData to 1 for PDFs with alpha

---
 src/PIL/PdfImagePlugin.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/PIL/PdfImagePlugin.py b/src/PIL/PdfImagePlugin.py
index 5d45461c5..fb3bac2ee 100644
--- a/src/PIL/PdfImagePlugin.py
+++ b/src/PIL/PdfImagePlugin.py
@@ -164,6 +164,7 @@ def _save(im, fp, filename, save_all=False):
                 # params = f"<< /Predictor 15 /Columns {width-2} >>"
                 colorspace = PdfParser.PdfName("DeviceGray")
                 procset = "ImageB"  # grayscale
+                dict_obj["SMaskInData"] = 1
             elif im.mode == "P":
                 filter = "ASCIIHexDecode"
                 palette = im.getpalette()