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diff --git a/test/update-refs.sh b/test/update-refs.sh
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+#!/bin/bash
+
+# This script can be used to update the reference images using certain
+# test results as a baseline.
+#
+# Our test suite expects nearly pixel-perfection, but in some cases we
+# give the renderer some flexibility and so these cases will show up as
+# test failures.  So, this script can be used to do a visual check and
+# if they "look" ok, to go ahead and update the reference image by
+# copying the test output.
+#
+# NOTE: When adding to this file, make sure to thoroughly document the
+# rationale when and why the existing reference images can be updated
+# from regular test output, such that people other than you can
+# intelligently keep the test reference images updated.
+
+if [ ! -d output ] || [ ! -d reference ]; then
+    echo "This script must be run in cairo's test directory after the full testsuite has been run."
+    exit
+fi
+
+PDIFF="./pdiff/perceptualdiff"
+
+# Returns 1 if images are different, 0 if they're essentially identical
+images_differ() {
+    # Check if bytewise identical
+    if cmp --silent "${1}" "${2}"; then
+	# Images are identical
+	return 0
+    fi
+
+    # Run perceptualdiff with minimum threshold
+    pdiff_output=$($PDIFF "${1}" "${2}" -threshold 1)
+    result=${pdiff_output%:*}
+    notes=$(echo "${pdiff_output#*: }" | tail -n 1)
+    if [ "$result" = "PASS" ] && [ "$notes" = "Images are binary identical" ]; then
+	return 0
+    fi
+
+    return 1
+}
+
+# ----------------------------------------------------------------------
+# pixman-downscale images
+#
+# The *-95 tests check rendering at a difficult to downsize dimension.
+# The border pixels between different colored areas can be blurred in
+# different ways resulting in some color variation that is acceptable
+# but throws off the testsuite.  So a visual check is sufficient to
+# verify the results aren't crazily off.
+
+# Use the ARGB32 format of the image file as the main reference
+for file in $(ls ./output/pixman-downscale-*-95.image.argb32.out.png); do
+    dest=$(basename ${file/.image.argb32.out./.ref.})
+    echo "$file -> ./reference/${dest}"
+    cp $file ./reference/${dest}
+done
+echo
+
+# If the ARGB32 format of a given backend's file differs from the main reference,
+# then use it as the backend reference
+for file in $(ls ./output/pixman-downscale-*-95.*.argb32.out.png); do
+    ref=$(basename ${file/-95.*.argb32.out.png/-95.ref.png})
+    if ! images_differ "./reference/${ref}" "${file}"; then
+	dest=$(basename ${file/.argb32.out.png/.ref.png})
+	echo "${file} -> ./reference/${dest}"
+	cp ${file} ./reference/${dest}
+    fi
+done
+echo
+
+# If the RGB24 format differs from existing ref image, then use it as a ref.
+for file in $(ls ./output/pixman-downscale-*-95.*.rgb24.out.png); do
+    ref=$(basename ${file/.rgb24.out.png/.ref.png})
+    if [ ! -e "./reference/${ref}" ]; then
+	ref=$(basename ${file/-95.*.rgb24.out.png/-95.ref.png})
+    fi
+
+    if ! images_differ "./reference/${ref}" "${file}"; then
+	dest=$(basename ${file/.rgb24.out.png/.rgb24.ref.png})
+	echo "${file} -> ./reference/${dest}"
+	cp ${file} ./reference/${dest}
+    fi
+done