Updated font id generation and image id (#222)

Generated font ID will now be the same across machines when generating
the same font file.
Generated image Id will now be the same across machines when generating
the same image file.

1 files changed, 16 insertions, 7 deletions

diff --git a/fpdf.go b/fpdf.go
index 400c83f..bc047b1 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -23,7 +23,6 @@ package gofpdf
 
 import (
 	"bytes"
-	"crypto/sha1"
 	"encoding/binary"
 	"encoding/json"
 	"fmt"
@@ -1578,9 +1577,12 @@ func (f *Fpdf) AddFontFromBytes(familyStr, styleStr string, jsonFileBytes, zFile
 		return
 	}
 
-	// search existing encodings
-	info.i = fmt.Sprintf("%x", sha1.Sum(jsonFileBytes))
+	if info.i, err = generateFontID(info); err != nil {
+		f.err = err
+		return
+	}
 
+	// search existing encodings
 	if len(info.Diff) > 0 {
 		n := -1
 
@@ -2523,7 +2525,7 @@ func (f *Fpdf) imageOut(info *ImageInfoType, x, y, w, h float64, allowNegativeX,
 	}
 	// dbg("h %.2f", h)
 	// q 85.04 0 0 NaN 28.35 NaN cm /I2 Do Q
-	f.outf("q %.5f 0 0 %.5f %.5f %.5f cm /I%d Do Q", w*f.k, h*f.k, x*f.k, (f.h-(y+h))*f.k, info.i)
+	f.outf("q %.5f 0 0 %.5f %.5f %.5f cm /I%s Do Q", w*f.k, h*f.k, x*f.k, (f.h-(y+h))*f.k, info.i)
 	if link > 0 || len(linkStr) > 0 {
 		f.newLink(x, y, w, h, link, linkStr)
 	}
@@ -2660,7 +2662,10 @@ func (f *Fpdf) RegisterImageOptionsReader(imgName string, options ImageOptions,
 	if f.err != nil {
 		return
 	}
-	info.i = len(f.images) + 1
+
+	if info.i, f.err = generateImageID(info); f.err != nil {
+		return
+	}
 	f.images[imgName] = info
 
 	return
@@ -2952,8 +2957,12 @@ func (f *Fpdf) loadfont(r io.Reader) (def fontDefType) {
 	err = json.Unmarshal(buf.Bytes(), &def)
 	if err != nil {
 		f.err = err
+		return
+	}
+
+	if def.i, err = generateFontID(def); err != nil {
+		f.err = err
 	}
-	def.i = fmt.Sprintf("%x", sha1.Sum(buf.Bytes()))
 	// dump(def)
 	return
 }
@@ -3556,7 +3565,7 @@ func (f *Fpdf) putxobjectdict() {
 		}
 		for _, key = range keyList {
 			image = f.images[key]
-			f.outf("/I%d %d 0 R", image.i, image.n)
+			f.outf("/I%s %d 0 R", image.i, image.n)
 		}
 	}
 	{