add code example

annotations/pdf_annotate_add_file.go

@@ -0,0 +1,126 @@
+/*
+ * Annotate/mark up pages of a PDF file.
+ * Adds a file attachment annotation placed in certain position in a page.
+ *
+ * Run as: go run pdf_annotate_add_file.go input.pdf output.pdf file_to_be_attached
+ */
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/unidoc/unipdf/v3/annotator"
+	"github.com/unidoc/unipdf/v3/common/license"
+	"github.com/unidoc/unipdf/v3/model"
+)
+
+func init() {
+	// Make sure to load your metered License API key prior to using the library.
+	// If you need a key, you can sign up and create a free one at https://cloud.unidoc.io
+	err := license.SetMeteredKey(os.Getenv(`UNIDOC_LICENSE_API_KEY`))
+	if err != nil {
+		panic(err)
+	}
+}
+
+func main() {
+	if len(os.Args) < 4 {
+		fmt.Printf("go run pdf_annotate_add_file.go input.pdf output.pdf file_to_be_attached\n")
+		os.Exit(1)
+	}
+
+	inputPath := os.Args[1]
+	outputPath := os.Args[2]
+	attachmentPath := os.Args[3]
+
+	err := annotatePdfAddFile(inputPath, outputPath, attachmentPath)
+	if err != nil {
+		fmt.Printf("Error: %v\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("Complete, see output file: %s\n", outputPath)
+}
+
+func annotatePdfAddFile(inputPath string, outputPath string, attachmentPath string) error {
+	// Read the input pdf file.
+	f, err := os.Open(inputPath)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	pdfReader, err := model.NewPdfReader(f)
+	if err != nil {
+		return err
+	}
+
+	page, err := pdfReader.GetPage(1)
+	if err != nil {
+		return err
+	}
+
+	// Instantiate embedded file object from existing file path.
+	emFile, err := model.NewEmbeddedFile(attachmentPath)
+	if err != nil {
+		return err
+	}
+
+	// Overwrite attachment name.
+	emFile.Name = "dummy.xml"
+	emFile.Description = "Sample Attachment"
+	emFile.Relationship = model.RelationshipData
+
+	creationTime := time.Now()
+
+	// Get the page media box.
+	box, err := page.GetMediaBox()
+	if err != nil {
+		return err
+	}
+
+	// Create a file attachment annotation definition.
+	fileAnnotDef := annotator.FileAnnotationDef{
+		// Position of the pin image.
+		X: box.Urx - 20,
+		Y: box.Ury - 20,
+
+		// Size of the pin image.
+		Width:  10,
+		Height: 15,
+
+		// Color of the pin image.
+		Color: model.NewPdfColorDeviceRGB(1.0, 0, 0),
+
+		EmbeddedFile: emFile,
+		Description:  emFile.Description,
+		IconName:     "Paperclip",
+		CreationDate: &creationTime,
+	}
+
+	// Create a file attachment annotation.
+	fileAnnot, err := annotator.CreateFileAttachmentAnnotation(fileAnnotDef)
+	if err != nil {
+		return err
+	}
+
+	// Add annotation to a page.
+	page.AddAnnotation(fileAnnot)
+
+	// Generate a PdfWriter instance from existing PdfReader.
+	pdfWriter, err := pdfReader.ToWriter(nil)
+	if err != nil {
+		return err
+	}
+
+	// Write to file.
+	err = pdfWriter.WriteToFile(outputPath)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}