Add golden files diff

+test/golden/* filter=lfs diff=lfs merge=lfs -text

@@ -43,5 +43,7 @@ printing/lcov.info
 test/readme.dart
 test/android
 test/ios
+test/diff
 
 ref
+!test/golden/*.pdf

@@ -4,6 +4,8 @@ addons:
   apt:
     packages:
       - lib32stdc++6
+      - poppler-utils
+      - imagemagick
 install:
   - git clone https://github.com/flutter/flutter.git -b stable --depth 1 $HOME/flutter
   - export PATH=$HOME/flutter/bin:$PATH

@@ -73,6 +73,7 @@ test-pdf: $(FONTS) get-pdf .coverage
 	dart --enable-asserts --disable-service-auth-codes --enable-vm-service=$(COV_PORT) --pause-isolates-on-exit test/all_tests.dart
 	cd pdf; pub global run coverage:format_coverage --packages=.packages -i coverage.json --report-on lib --lcov --out lcov.info
 	cd pdf; for EXAMPLE in $(shell cd pdf; find example -name '*.dart'); do dart $$EXAMPLE; done
+	test/compare-pdf.sh pdf test/golden
 
 test-printing: $(FONTS) get-printing .coverage
 	cd printing/example; flutter test --coverage --coverage-path ../lcov.info
@@ -107,12 +108,12 @@ publish-printing: format clean
 
 analyze-pdf: .pana
 	@find pdf -name pubspec.yaml -exec sed -i -e 's/^dependency_overrides:/_dependency_overrides:/g' '{}' ';'
-	@pub global run pana --no-warning --source path pdf 2> /dev/null | python pana_report.py
+	@pub global run pana --no-warning --source path pdf 2> /dev/null | python test/pana_report.py
 	@find pdf -name pubspec.yaml -exec sed -i -e 's/^_dependency_overrides:/dependency_overrides:/g' '{}' ';'
 
 analyze-printing: .pana
 	@find printing -name pubspec.yaml -exec sed -i -e 's/^dependency_overrides:/_dependency_overrides:/g' '{}' ';'
-	@pub global run pana --no-warning --source path printing 2> /dev/null | python pana_report.py
+	@pub global run pana --no-warning --source path printing 2> /dev/null | python test/pana_report.py
 	@find printing -name pubspec.yaml -exec sed -i -e 's/^_dependency_overrides:/dependency_overrides:/g' '{}' ';'
 
 analyze: analyze-pdf analyze-printing

+#!/bin/bash
+
+DST=$(dirname "$0")/diff
+SRC=$1
+GOLD=$2
+ERROR=0
+DPI=50
+COMPARE=$(command -v compare)
+
+for PDF in "$SRC"/*.pdf; do
+  echo "Diffing $PDF"
+  G="$GOLD"/$(basename "$PDF")
+  if [ ! -f "$G" ]; then
+    echo "   Golden image $G not found"
+    ERROR=1
+    continue
+  fi
+
+  T=$(basename "$PDF" .pdf)
+  mkdir -p "$DST"/"$T"
+  pdftocairo "$PDF" -png -r "$DPI" "$DST"/"$T"/src 2> /dev/null
+  pdftocairo "$G" -png -r "$DPI" "$DST"/"$T"/gold 2> /dev/null
+
+  for PNG in "$DST"/"$T"/gold*.png; do
+    S="$DST"/"$T"/src-"${PNG##*-}"
+    RES=$($COMPARE -metric AE "$PNG" "$S" null: 2>&1)
+    if [ "$RES" != "0" ]; then
+      D="$DST"/"$T"/diff-"${PNG##*-}"
+      $COMPARE "$PNG" "$S" -highlight-color red "$D"
+      echo "   Differences in $PNG and $S => $D"
+      ERROR=1
+    fi
+  done
+done
+
+if [ $ERROR -eq 0 ]; then
+  rm -rf "$DST"
+fi
+
+exit $ERROR