From e1b7bbbc0af7c2c0cf8e1286e80f7fbbe1c4c49f Mon Sep 17 00:00:00 2001
From: Adrian Johnson <ajohnson@redneon.com>
Date: Sat, 14 Oct 2017 07:48:11 +1030
Subject: [PATCH] cairo: use custom downscaling for scaling < 0.5

---
 poppler/CairoOutputDev.cc | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/poppler/CairoOutputDev.cc b/poppler/CairoOutputDev.cc
index 80f7a99e..77183009 100644
--- a/poppler/CairoOutputDev.cc
+++ b/poppler/CairoOutputDev.cc
@@ -3085,7 +3085,16 @@ public:
     bool needsCustomDownscaling = true;
 #endif
 
-    if (!needsCustomDownscaling || printing || scaledWidth >= width || scaledHeight >= height) {
+    bool useCustomDownscaling = false;
+    if (!printing) {
+      if (needsCustomDownscaling && scaledWidth < width && scaledHeight < height)
+	useCustomDownscaling = true;
+
+      if (width/scaledWidth > 2 || height/scaledHeight > 2)
+	useCustomDownscaling = true;
+    }
+
+    if (!useCustomDownscaling) {
       // No downscaling. Create cairo image containing the source image data.
       unsigned char *buffer;
       int stride;
-- 
2.11.0