From bbaeac8fa0475f2ff753a65b2dff495c5fe2a3ca Mon Sep 17 00:00:00 2001
From: Igor Mikushkin <igor.mikushkin@gmail.com>
Date: Sun, 25 Nov 2018 15:11:10 +0400
Subject: [PATCH] internal/cmpimg: PDF comparison fixed

---
 internal/cmpimg/cmpimg.go                 |  67 ++++++++++++++++++----
 plotter/testdata/polygon_holes_golden.pdf | Bin 214258 -> 214250 bytes
 2 files changed, 56 insertions(+), 11 deletions(-)

diff --git a/internal/cmpimg/cmpimg.go b/internal/cmpimg/cmpimg.go
index 3d0c3394..907e9499 100644
--- a/internal/cmpimg/cmpimg.go
+++ b/internal/cmpimg/cmpimg.go
@@ -12,6 +12,7 @@ import (
 	"image"
 	"image/color"
 	"image/draw"
+	"io/ioutil"
 	"math"
 	"reflect"
 	"strings"
@@ -81,23 +82,67 @@ func Equal(typ string, raw1, raw2 []byte) (bool, error) {
 }
 
 func cmpPdf(pdf1, pdf2 *pdf.Reader) bool {
-	n1 := pdf1.NumPage()
-	n2 := pdf2.NumPage()
-	if n1 != n2 {
+	return cmpPdfValues(pdf1.Trailer(), pdf2.Trailer())
+}
+
+func cmpPdfValues(v1, v2 pdf.Value) bool {
+	if v1.Kind() != v2.Kind() {
 		return false
 	}
 
-	for i := 1; i <= n1; i++ {
-		p1 := pdf1.Page(i).Content()
-		p2 := pdf2.Page(i).Content()
-		if !reflect.DeepEqual(p1, p2) {
+	switch v1.Kind() {
+	case pdf.String:
+		return v1.String() == v2.String()
+	case pdf.Integer:
+		return v1.Int64() == v2.Int64()
+	case pdf.Real:
+		return v1.Float64() == v2.Float64()
+	case pdf.Name:
+		return v1.Name() == v2.Name()
+	case pdf.Stream:
+		r1 := v1.Reader()
+		s1, err1 := ioutil.ReadAll(r1)
+		r1.Close()
+		r2 := v2.Reader()
+		s2, err2 := ioutil.ReadAll(r2)
+		r2.Close()
+		if err1 != nil || err2 != nil || len(s1) != len(s2) {
+			return false
+		}
+		if !bytes.Equal(s1, s2) {
+			return false
+		}
+		fallthrough
+	case pdf.Dict:
+		keys1, keys2 := v1.Keys(), v2.Keys()
+		if len(keys1) != len(keys2) {
+			return false
+		}
+		for i, k := range keys1 {
+			if k != keys2[i] {
+				return false
+			}
+			if k == "CreationDate" || k == "Parent" || k == "Font" {
+				continue
+			}
+			if !cmpPdfValues(v1.Key(k), v2.Key(k)) {
+				return false
+			}
+		}
+		return true
+	case pdf.Array:
+		if v1.Len() != v2.Len() {
 			return false
 		}
+		count := v1.Len()
+		for i := 0; i < count; i++ {
+			if !cmpPdfValues(v1.Index(i), v2.Index(i)) {
+				return false
+			}
+		}
+		return true
 	}
-
-	t1 := pdf1.Trailer().String()
-	t2 := pdf2.Trailer().String()
-	return t1 == t2
+	return false
 }
 
 // Diff calculates an intensity-scaled difference between images a and b
diff --git a/plotter/testdata/polygon_holes_golden.pdf b/plotter/testdata/polygon_holes_golden.pdf
index 58dd95ad3a10b1f198a40bf4244b19da3adc8a2b..dc7608fa17f134562c8b19410ee24ac223354d41 100644
GIT binary patch
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