add the ability to include JavaScript in PDFs (#117)

3 files changed, 45 insertions, 0 deletions

diff --git a/def.go b/def.go
index 54abbd1..c80eb37 100644
--- a/def.go
+++ b/def.go
@@ -247,6 +247,8 @@ type Fpdf struct {
 	protect          protectType               // document protection structure
 	layer            layerRecType              // manages optional layers in document
 	catalogSort      bool                      // sort resource catalogs in document
+	nJs              int                       // JavaScript object number
+	javascript       *string                   // JavaScript code to include in the PDF
 	colorFlag        bool                      // indicates whether fill and text colors are different
 	color            struct {
 		// Composite values of colors
diff --git a/fpdf.go b/fpdf.go
index 8ab2339..78a7c65 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -3028,6 +3028,11 @@ func (f *Fpdf) SetCreationDate(tm time.Time) {
 	f.creationDate = tm
 }
 
+// SetJavascript adds Adobe JavaScript to the document.
+func (f *Fpdf) SetJavascript(script string) {
+	f.javascript = &script
+}
+
 func (f *Fpdf) putpages() {
 	var wPt, hPt float64
 	var pageSize SizeType
@@ -3475,6 +3480,25 @@ func (f *Fpdf) putGradients() {
 	}
 }
 
+func (f *Fpdf) putjavascript() {
+	if f.javascript == nil {
+		return
+	}
+
+	f.newobj()
+	f.nJs = f.n
+	f.out("<<")
+	f.outf("/Names [(EmbeddedJS) %d 0 R]", f.n+1)
+	f.out(">>")
+	f.out("endobj")
+	f.newobj()
+	f.out("<<")
+	f.out("/S /JavaScript")
+	f.outf("/JS %s", f.textstring(*f.javascript))
+	f.out(">>")
+	f.out("endobj")
+}
+
 func (f *Fpdf) putresources() {
 	if f.err != nil {
 		return
@@ -3495,6 +3519,7 @@ func (f *Fpdf) putresources() {
 	f.putresourcedict()
 	f.out(">>")
 	f.out("endobj")
+	f.putjavascript()
 	if f.protect.encrypted {
 		f.newobj()
 		f.protect.objNum = f.n
@@ -3572,6 +3597,10 @@ func (f *Fpdf) putcatalog() {
 	}
 	// Layers
 	f.layerPutCatalog()
+	// JavaScript
+	if f.javascript != nil {
+		f.outf("/Names <</JavaScript %d 0 R>>", f.nJs)
+	}
 }
 
 func (f *Fpdf) putheader() {
diff --git a/fpdf_test.go b/fpdf_test.go
index 456295c..5781ad6 100644
--- a/fpdf_test.go
+++ b/fpdf_test.go
@@ -1857,3 +1857,17 @@ func ExampleFpdf_Rect() {
 	// Output:
 	// Successfully generated pdf/Fpdf_WrappedTableCells.pdf
 }
+
+// This example demonstrates including JavaScript in the document.
+func ExampleFpdf_SetJavascript() {
+	pdf := gofpdf.New("P", "mm", "A4", "")
+	pdf.SetJavascript("print(true);")
+	pdf.AddPage()
+	pdf.SetFont("Arial", "", 12)
+	pdf.Write(10, "Auto-print.")
+	fileStr := example.Filename("Fpdf_SetJavascript")
+	err := pdf.OutputFileAndClose(fileStr)
+	example.Summary(err, fileStr)
+	// Output:
+	// Successfully generated pdf/Fpdf_SetJavascript.pdf
+}